This essay discusses how the ultrastructural changes in chloroplasts, particularly the mechanisms of thylakoid membrane unstacking, help maintain the photosynthetic performance of photosystem II (PSII) under stress conditions. This phenomenon may facilitate the repair of damaged PSII by providing access to the repair machinery. It is argued that this PSII repair mechanism accelerates PSII recovery, optimizing photosynthetic processes in stressed plants. Although some studies demonstrate the relationship between thylakoid membrane unstacking in stress conditions, these studies were developed with model species under controlled conditions. Thus, this essay serves as a validation tool for these previous studies, because it demonstrates that the relationships between ultrastructural changes in chloroplasts and the functioning of PSII are essential acclimative strategies for nonmodel plants to survive the constant edaphoclimatic changes of natural environments. Understanding these subcellular dynamics can significantly inform biologists about the plastic potential of plants, especially in heterogeneous environments. An integrated approach in future studies is necessary, highlighting the importance of exploring plant functional traits at multiple scales, because subcellular characteristics have great potential to understand plant acclimatization.
{"title":"Unraveling subcellular functional traits: Adaptive insights into chloroplast ultrastructure in nonmodel species","authors":"Saulo Pireda, Maura Da Cunha","doi":"10.1002/ajb2.16415","DOIUrl":"10.1002/ajb2.16415","url":null,"abstract":"<p>This essay discusses how the ultrastructural changes in chloroplasts, particularly the mechanisms of thylakoid membrane unstacking, help maintain the photosynthetic performance of photosystem II (PSII) under stress conditions. This phenomenon may facilitate the repair of damaged PSII by providing access to the repair machinery. It is argued that this PSII repair mechanism accelerates PSII recovery, optimizing photosynthetic processes in stressed plants. Although some studies demonstrate the relationship between thylakoid membrane unstacking in stress conditions, these studies were developed with model species under controlled conditions. Thus, this essay serves as a validation tool for these previous studies, because it demonstrates that the relationships between ultrastructural changes in chloroplasts and the functioning of PSII are essential acclimative strategies for nonmodel plants to survive the constant edaphoclimatic changes of natural environments. Understanding these subcellular dynamics can significantly inform biologists about the plastic potential of plants, especially in heterogeneous environments. An integrated approach in future studies is necessary, highlighting the importance of exploring plant functional traits at multiple scales, because subcellular characteristics have great potential to understand plant acclimatization.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16415","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142387328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sonal Singhal, Christopher DiVittorio, Chandra Jones, Itzel Ixta, Alexis Widmann, Ivone Giffard-Mena, Felipe Zapata, Adam Roddy
Premise
Clines—or the geographic sorting of phenotypes across continual space—provide an opportunity to understand the interaction of dispersal, selection, and history in structuring polymorphisms.
Methods
In this study, we combine field-sampling, genetics, climatic analyses, and machine learning to understand a flower color polymorphism in the wide-ranging desert annual Encelia farinosa.
Results
We find evidence for replicated transitions in disk floret color from brown to yellow across spatial scales, with the most prominent cline stretching ~100 km from southwestern United States into México. Because population structure across the cline is minimal, selection is more likely than drift to have an important role in determining cline width.
Conclusions
Given that the cline aligns with a climatic transition but there is no evidence for pollinator preference for flower color, we hypothesize that floret color likely varies as a function of climatic conditions.
{"title":"Population structure and natural selection across a flower color polymorphism in the desert plant Encelia farinosa","authors":"Sonal Singhal, Christopher DiVittorio, Chandra Jones, Itzel Ixta, Alexis Widmann, Ivone Giffard-Mena, Felipe Zapata, Adam Roddy","doi":"10.1002/ajb2.16413","DOIUrl":"10.1002/ajb2.16413","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Clines—or the geographic sorting of phenotypes across continual space—provide an opportunity to understand the interaction of dispersal, selection, and history in structuring polymorphisms.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this study, we combine field-sampling, genetics, climatic analyses, and machine learning to understand a flower color polymorphism in the wide-ranging desert annual <i>Encelia farinosa</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We find evidence for replicated transitions in disk floret color from brown to yellow across spatial scales, with the most prominent cline stretching ~100 km from southwestern United States into México. Because population structure across the cline is minimal, selection is more likely than drift to have an important role in determining cline width.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Given that the cline aligns with a climatic transition but there is no evidence for pollinator preference for flower color, we hypothesize that floret color likely varies as a function of climatic conditions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16413","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ledis Regalado, Marc S. Appelhans, Anja Poehlein, Axel Himmelbach, Alexander R. Schmidt
Premise
Molecular studies based on chloroplast markers have questioned the monophyly of the fern genus Pecluma (Polypodioideae, Polypodiaceae), which has several species of Polypodium nested within it. We explored the delimitation of Pecluma and its biogeographic pattern by evaluating the phylogenetic position of four Polypodium species not sequenced thus far and integrating the first fossil evidence of Pecluma.
Methods
Using herbarium material, we applied a genome-skimming approach to obtain a phylogenetic hypothesis of Polypodioideae; assessed the combination of character states observed in the fossil from Miocene Dominican amber using a previously published phylogeny of Polypodioideae based on four plastid markers as framework; calculated divergence times; and conducted an ancestral area estimation.
Results
Within Polypodioideae, Pecluma was recovered as sister to Phlebodium. Three of the newly sequenced species—Polypodium otites, P. pinnatissimum, and P. ursipes—were recovered with maximum support within the Pecluma clade, whereas P. christensenii remained within Polypodium. The closest combination of character states of the fossil was found within Pecluma. Our biogeographic analyses suggest an Eocene origin of the genus in South America, with several subsequent Oligocene and Miocene colonization events to Mexico–Central America and to the West Indies.
Conclusions
Although the circumscription of Pecluma is still challenging, our results elucidate the origin and age of the genus. The newly described fossil, Pecluma hispaniolae sp. nov., supports the hypothesis that the epiphytic communities of the Greater Antilles exhibit a constant generic composition since the Miocene. We propose new combinations (Pecluma otites, Pecluma pinnatissima, and Pecluma ursipes) to accommodate three species previously classified in Polypodium.
{"title":"Plastome phylogenomics and new fossil evidence from Dominican amber shed light on the evolutionary history of the Neotropical fern genus Pecluma","authors":"Ledis Regalado, Marc S. Appelhans, Anja Poehlein, Axel Himmelbach, Alexander R. Schmidt","doi":"10.1002/ajb2.16410","DOIUrl":"10.1002/ajb2.16410","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Molecular studies based on chloroplast markers have questioned the monophyly of the fern genus <i>Pecluma</i> (Polypodioideae, Polypodiaceae), which has several species of <i>Polypodium</i> nested within it. We explored the delimitation of <i>Pecluma</i> and its biogeographic pattern by evaluating the phylogenetic position of four <i>Polypodium</i> species not sequenced thus far and integrating the first fossil evidence of <i>Pecluma</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using herbarium material, we applied a genome-skimming approach to obtain a phylogenetic hypothesis of Polypodioideae; assessed the combination of character states observed in the fossil from Miocene Dominican amber using a previously published phylogeny of Polypodioideae based on four plastid markers as framework; calculated divergence times; and conducted an ancestral area estimation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Within Polypodioideae, <i>Pecluma</i> was recovered as sister to <i>Phlebodium</i>. Three of the newly sequenced species—<i>Polypodium otites</i>, <i>P. pinnatissimum</i>, and <i>P. ursipes</i>—were recovered with maximum support within the <i>Pecluma</i> clade, whereas <i>P. christensenii</i> remained within <i>Polypodium</i>. The closest combination of character states of the fossil was found within <i>Pecluma</i>. Our biogeographic analyses suggest an Eocene origin of the genus in South America, with several subsequent Oligocene and Miocene colonization events to Mexico–Central America and to the West Indies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Although the circumscription of <i>Pecluma</i> is still challenging, our results elucidate the origin and age of the genus. The newly described fossil, <i>Pecluma hispaniolae</i> sp. nov., supports the hypothesis that the epiphytic communities of the Greater Antilles exhibit a constant generic composition since the Miocene. We propose new combinations (<i>Pecluma otites</i>, <i>Pecluma pinnatissima</i>, and <i>Pecluma ursipes</i>) to accommodate three species previously classified in <i>Polypodium</i>.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16410","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Isabella H. Vergara, Monica A. Geber, David A. Moeller, Vincent M. Eckhart
Premise
Seed germination involves risk; post-germination conditions might not allow survival and reproduction. Variable, stressful environments favor seeds with germination that avoids risk (e.g., germination in conditions predicting success), spreads risk (e.g., dormancy), or escapes risk (e.g., rapid germination). Germination studies often investigate trait correlations with climate features linked to variation in post-germination reproductive success. Rarely are long-term records of population reproductive success available.
Methods
Supported by demographic and climate monitoring, we analyzed germination in the California winter-annual Clarkia xantiana subsp. xantiana. Sowing seeds of 10 populations across controlled levels of water potential and temperature, we estimated temperature-specific base water potential for 20% germination, germination time weighted by water potential above base (hydrotime), and a dormancy index (frequency of viable, ungerminated seeds). Mixed-effects models analyzed responses to (1) temperature, (2) discrete variation in reproductive success (presence or absence of years with zero seed production by a population), and (3) climate covariates, mean winter precipitation and coefficient of variation (CV) of spring precipitation. For six populations, records enabled analysis with a continuous metric of variable reproduction, the CV of per-capita reproductive success.
Results
Populations with more variable reproductive success had higher base water potential and dormancy. Higher base water potential and faster germination occurred at warmer experimental temperatures and in seeds of populations with wetter winters.
Conclusions
Geographic variation in seed germination in this species suggests local adaptation to demographic risk and rainfall. High base water potential and dormancy may concentrate germination in years likely to allow reproduction, while spreading risk among years.
{"title":"Population histories of variable reproductive success and low winter precipitation correlate with risk-averse seed germination in a mediterranean-climate winter annual","authors":"Isabella H. Vergara, Monica A. Geber, David A. Moeller, Vincent M. Eckhart","doi":"10.1002/ajb2.16412","DOIUrl":"10.1002/ajb2.16412","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Seed germination involves risk; post-germination conditions might not allow survival and reproduction. Variable, stressful environments favor seeds with germination that avoids risk (e.g., germination in conditions predicting success), spreads risk (e.g., dormancy), or escapes risk (e.g., rapid germination). Germination studies often investigate trait correlations with climate features linked to variation in post-germination reproductive success. Rarely are long-term records of population reproductive success available.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Supported by demographic and climate monitoring, we analyzed germination in the California winter-annual <i>Clarkia xantiana</i> subsp. <i>xantiana</i>. Sowing seeds of 10 populations across controlled levels of water potential and temperature, we estimated temperature-specific base water potential for 20% germination, germination time weighted by water potential above base (hydrotime), and a dormancy index (frequency of viable, ungerminated seeds). Mixed-effects models analyzed responses to (1) temperature, (2) discrete variation in reproductive success (presence or absence of years with zero seed production by a population), and (3) climate covariates, mean winter precipitation and coefficient of variation (CV) of spring precipitation. For six populations, records enabled analysis with a continuous metric of variable reproduction, the CV of per-capita reproductive success.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Populations with more variable reproductive success had higher base water potential and dormancy. Higher base water potential and faster germination occurred at warmer experimental temperatures and in seeds of populations with wetter winters.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Geographic variation in seed germination in this species suggests local adaptation to demographic risk and rainfall. High base water potential and dormancy may concentrate germination in years likely to allow reproduction, while spreading risk among years.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
While some studies have found leaf variegation to reduce photosynthetic capacity, others showed that it can increase photosynthesis. Thus, what maintains variegation remains an open question. Two primary hypotheses—the anti-herbivory and abiotic heterogeneity hypotheses—have been posited, yet little empirical research explicitly investigates the maintenance of naturally occurring variegation.
Methods
We used field surveys, image analysis, and climatic associations to explore the anti-herbivory and abiotic heterogeneity hypotheses in 21 populations of Hexastylis heterophylla and H. shuttleworthii, both polymorphic for leaf variegation. We measured the frequency of variegated individuals, variegation intensity, and herbivory for each morph, assessed abiotic correlates with variegation, and measured photosynthetic efficiency.
Results
We found a strong elevational cline in leaf variegation strongly linked with abiotic heterogeneity; variegation was more common in lower-elevation populations characterized by higher temperatures, UV-B exposure, seasonal light change, and drier, more basic soils. Variegated and nonvariegated individuals experienced similar levels of herbivory. Morphs had similar photosynthetic quantum yields. However, nonvariegated leaves experienced more nonphotochemical quenching, an indication of photoinhibition, and had higher surface temperatures under high light.
Conclusions
Our results suggest that variegation may serve as an adaptation to high temperatures and light conditions and can reduce photoinhibition in certain environmental contexts. Thus, abiotic factors can maintain variegation in wild populations and shape geographic clines in variegation.
前提：一些研究发现叶片变色会降低光合作用能力，而另一些研究则表明叶片变色可以提高光合作用。因此，是什么维持了叶片的变色仍然是一个悬而未决的问题。人们提出了两个主要假说--反食草动物假说和非生物异质性假说，但很少有实证研究明确调查自然发生的变色的维持情况：方法：我们利用实地调查、图像分析和气候关联，在 21 个叶片变异多态的 Hexastylis heterophylla 和 H. shuttleworthii 种群中探讨了反食草动物假说和非生物异质性假说。我们测量了每种形态的变异个体频率、变异强度和草食性，评估了与变异相关的非生物因素，并测量了光合效率：我们发现叶片变色与非生物异质性密切相关，叶片变色在海拔较低的种群中更为常见，这些种群的特点是温度较高、紫外线-B照射较强、季节性光照变化较大、土壤较为干燥和碱性较强。变色个体和非变色个体遭受的草食程度相似。形态的光合量子产率相似。然而，非变色叶片经历了更多的非光化学淬灭（这是光抑制的一种表现），并且在强光下表面温度更高：我们的研究结果表明，变色可能是对高温和光照条件的一种适应，在某些环境条件下可以减少光抑制。因此，非生物因素可以维持野生种群的变异，并形成变异的地理支系。
{"title":"An elevational cline in leaf variegation: Testing anti-herbivory and abiotic heterogeneity hypotheses in maintaining a polymorphism","authors":"Cierra N. Sullivan, Matthew H. Koski","doi":"10.1002/ajb2.16411","DOIUrl":"10.1002/ajb2.16411","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>While some studies have found leaf variegation to reduce photosynthetic capacity, others showed that it can increase photosynthesis. Thus, what maintains variegation remains an open question. Two primary hypotheses—the anti-herbivory and abiotic heterogeneity hypotheses—have been posited, yet little empirical research explicitly investigates the maintenance of naturally occurring variegation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used field surveys, image analysis, and climatic associations to explore the anti-herbivory and abiotic heterogeneity hypotheses in 21 populations of <i>Hexastylis heterophylla</i> and <i>H. shuttleworthii</i>, both polymorphic for leaf variegation. We measured the frequency of variegated individuals, variegation intensity, and herbivory for each morph, assessed abiotic correlates with variegation, and measured photosynthetic efficiency.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found a strong elevational cline in leaf variegation strongly linked with abiotic heterogeneity; variegation was more common in lower-elevation populations characterized by higher temperatures, UV-B exposure, seasonal light change, and drier, more basic soils. Variegated and nonvariegated individuals experienced similar levels of herbivory. Morphs had similar photosynthetic quantum yields. However, nonvariegated leaves experienced more nonphotochemical quenching, an indication of photoinhibition, and had higher surface temperatures under high light.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results suggest that variegation may serve as an adaptation to high temperatures and light conditions and can reduce photoinhibition in certain environmental contexts. Thus, abiotic factors can maintain variegation in wild populations and shape geographic clines in variegation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16411","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Increasing aridity in the Mediterranean region affects ecosystems and plant life. Various anatomical changes in plants help them cope with dry conditions. This study focused on anatomical differences in leaves and xylem of five co-occurring Mediterranean plant species namely Quercus calliprinos, Pistacia palaestina, Pistacia lentiscus, Rhamnus lycioides, and Phillyrea latifolia in wet and dry sites.
Methods
Stomatal density, stomatal length, leaf mass area, lamina composition, percentage of intercellular air spaces, and mesophyll cell area in leaves of plants in wet and dry sites were analyzed. Xylem anatomy was assessed through vessel length and area in branches.
Results
In the dry site, three species had increased stomatal density and decreased stomatal length. Four species had increased palisade mesophyll and reduced air space volume. In contrast, phenotypic changes in the xylem were less pronounced; vessel length was unaffected by site conditions, but vessel diameter decreased in two species. Intercellular air spaces proved to be the most dynamic anatomical feature. Quercus calliprinos had the most extensive anatomical changes; Rhamnus lycioides had only minor changes. All these changes were observed in comparison to the species in the wet site.
Conclusions
This study elucidated variations in anatomical responses in leaves among co-occurring Mediterranean plant species and identified the most dynamic traits. Understanding these adaptations provides valuable insights into the ability of plants to thrive under changing climate conditions.
{"title":"Growing at the arid edge: Anatomical variations in leaves are more extensive than in stems of five Mediterranean species across contrasting moisture regimes","authors":"Asaf Alon, Neta Ginzburg, Hanita Zemach, Hillary Voet, Shabtai Cohen, Rakefet David-Schwartz","doi":"10.1002/ajb2.16407","DOIUrl":"10.1002/ajb2.16407","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Increasing aridity in the Mediterranean region affects ecosystems and plant life. Various anatomical changes in plants help them cope with dry conditions. This study focused on anatomical differences in leaves and xylem of five co-occurring Mediterranean plant species namely <i>Quercus calliprinos</i>, <i>Pistacia palaestina</i>, <i>Pistacia lentiscus</i>, <i>Rhamnus lycioides</i>, and <i>Phillyrea latifolia</i> in wet and dry sites.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Stomatal density, stomatal length, leaf mass area, lamina composition, percentage of intercellular air spaces, and mesophyll cell area in leaves of plants in wet and dry sites were analyzed. Xylem anatomy was assessed through vessel length and area in branches.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In the dry site, three species had increased stomatal density and decreased stomatal length. Four species had increased palisade mesophyll and reduced air space volume. In contrast, phenotypic changes in the xylem were less pronounced; vessel length was unaffected by site conditions, but vessel diameter decreased in two species. Intercellular air spaces proved to be the most dynamic anatomical feature. <i>Quercus calliprinos</i> had the most extensive anatomical changes; <i>Rhamnus lycioides</i> had only minor changes. All these changes were observed in comparison to the species in the wet site.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study elucidated variations in anatomical responses in leaves among co-occurring Mediterranean plant species and identified the most dynamic traits. Understanding these adaptations provides valuable insights into the ability of plants to thrive under changing climate conditions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142279123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Plants generate a wide array of signals such as olfactory cues to attract and manipulate the response of pollinators. The present study addresses the temporal patterns of scent emission as an additional dimension to the scent composition. The expectation is that divergent floral function is reflected in divergent qualitative and temporal emission patterns.
Methods
We used GC-ion mobility spectrometry with an integrated pre-concentration for automated acquisition of the temporal trends in floral volatile emissions for N. viridiflorus, N. papyraceus, and N. cantabricus subsp. foliosus.
Results
We found a considerable increase in scent emissions and changes in scent composition for N. viridiflorus at night. This increase was particularly pronounced for aromatic substances such as benzyl acetate and p-cresol. We found no diurnal patterns in N. papyraceus, despite a similar qualitative composition of floral volatiles. Narcissus cantabricus subsp. foliosus showed no diurnal patterns either and differed considerably in floral scent composition.
Conclusions
Scent composition, circadian emission patterns, and floral morphology indicate divergent, but partially overlapping pollinator communities. However, the limited pollinator data from the field only permits a tentative correlation between emission patterns and flower visitors. Narcissus papyraceus and N. cantabricus show no clear diurnal patterns and thus no adjustment to the activity patterns of their diurnal pollinators. In N. viridiflorus, timing of scent emission indicates an adaptation to nocturnal flower visitors, contradicting Macroglossum as the only reported pollinator. We propose that the legitimate pollinators of N. viridiflorus are nocturnal and are still unidentified.
前言：植物会产生各种各样的信号，如嗅觉线索，以吸引和操纵传粉昆虫的反应。本研究将香味释放的时间模式作为香味组成的另一个维度。预计不同的花卉功能会反映在不同的质量和时间释放模式上：方法：我们使用集成预浓缩功能的气相色谱-离子迁移谱法，自动获取 N. viridiflorus、N. papyraceus 和 N. cantabricus subsp：结果：我们发现在夜间，N. viridiflorus 的花香释放量大幅增加，花香成分也发生了变化。芳香物质（如乙酸苄酯和对甲酚）的增加尤为明显。我们在纸莎草中没有发现昼夜变化规律，尽管花挥发物的质量成分相似。水仙亚种（Narcissus cantabricus subsp. foliosus）也没有显示出昼夜模式，花香成分差异很大：结论：气味成分、昼夜节律释放模式和花朵形态表明传粉昆虫群落存在差异，但也有部分重叠。然而，来自野外的授粉昆虫数据有限，只能初步确定散发模式与访花者之间的相关性。纸莎草水仙（Narcissus papyraceus）和水仙（N. cantabricus）没有显示出明显的昼夜模式，因此无法调整其昼间传粉昆虫的活动模式。在水仙（N. viridiflorus）中，香味散发的时间表明其适应了夜间访花者的活动，这与唯一报道的授粉者猕猴桃（Macroglossum）相矛盾。我们认为，N. viridiflorus 的合法传粉者是夜间活动的，目前仍未确定。
{"title":"Diurnal patterns of floral volatile emissions in three species of Narcissus","authors":"Florian Losch, Maximilian Weigend","doi":"10.1002/ajb2.16408","DOIUrl":"10.1002/ajb2.16408","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Plants generate a wide array of signals such as olfactory cues to attract and manipulate the response of pollinators. The present study addresses the temporal patterns of scent emission as an additional dimension to the scent composition. The expectation is that divergent floral function is reflected in divergent qualitative and temporal emission patterns.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used GC-ion mobility spectrometry with an integrated pre-concentration for automated acquisition of the temporal trends in floral volatile emissions for <i>N. viridiflorus</i>, <i>N. papyraceus</i>, and <i>N. cantabricus</i> subsp<i>. foliosus</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found a considerable increase in scent emissions and changes in scent composition for <i>N. viridiflorus</i> at night. This increase was particularly pronounced for aromatic substances such as benzyl acetate and <i>p</i>-cresol. We found no diurnal patterns in <i>N. papyraceus</i>, despite a similar qualitative composition of floral volatiles. <i>Narcissus cantabricus</i> subsp. <i>foliosus</i> showed no diurnal patterns either and differed considerably in floral scent composition.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Scent composition, circadian emission patterns, and floral morphology indicate divergent, but partially overlapping pollinator communities. However, the limited pollinator data from the field only permits a tentative correlation between emission patterns and flower visitors. <i>Narcissus papyraceus</i> and <i>N. cantabricus</i> show no clear diurnal patterns and thus no adjustment to the activity patterns of their diurnal pollinators. In <i>N. viridiflorus</i>, timing of scent emission indicates an adaptation to nocturnal flower visitors, contradicting <i>Macroglossum</i> as the only reported pollinator. We propose that the legitimate pollinators of <i>N. viridiflorus</i> are nocturnal and are still unidentified.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16408","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142279122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
William H. Brightly, Ana M. Bedoya, McKenzie M. Carlson, Maria G. Rottersman, Caroline A. E. Strömberg
Premise
Seed dispersal is a critical process impacting individual plants and their communities. Plants have evolved numerous strategies and structures to disperse their seeds, but the evolutionary drivers of this diversity remain poorly understood in most lineages. We tested the hypothesis that the evolution of wind dispersal traits within the melicgrasses (Poaceae: Meliceae Link ex Endl.) was correlated with occupation of open and disturbed habitats.
Methods
To evaluate wind dispersal potential, we collected seed dispersal structures (diaspores) from 24 melicgrass species and measured falling velocity and estimated dispersal distances. Species’ affinity for open and disturbed habitats were recorded using georeferenced occurrence records and land cover maps. To test whether habitat preference and dispersal traits were correlated, we used phylogenetically informed multilevel models.
Results
Melicgrasses display several distinct morphologies associated with wind dispersal, suggesting likely convergence. Open habitat taxa had slower-falling diaspores, consistent with increased wind dispersal potential. However, their shorter stature meant that dispersal distances, at a given wind speed, were not higher than those of their forest-occupying relatives. Species with affinities for disturbed sites had slower-falling diaspores and greater wind dispersal distances, largely explained by lighter diaspores.
Conclusions
Our results are consistent with the hypothesized evolutionary relationship between habitat preference and dispersal strategy. However, phylogenetic inertia and other plant functions (e.g., water conservation) likely shaped dispersal trait evolution in melicgrasses. It remains unclear if dispersal trait changes were precipitated by or predated changing habitat preferences. Nevertheless, our study provides promising results and a framework for disentangling dispersal strategy evolution.
种子传播是影响植物个体及其群落的一个关键过程。植物已经进化出许多策略和结构来散播种子，但在大多数品系中，这种多样性的进化驱动因素仍然鲜为人知。我们测试了一个假设，即瓜子黄杨（Poaceae: Meliceae Link ex Endl.）
{"title":"Correlated evolution of dispersal traits and habitat preference in the melicgrasses","authors":"William H. Brightly, Ana M. Bedoya, McKenzie M. Carlson, Maria G. Rottersman, Caroline A. E. Strömberg","doi":"10.1002/ajb2.16406","DOIUrl":"10.1002/ajb2.16406","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Seed dispersal is a critical process impacting individual plants and their communities. Plants have evolved numerous strategies and structures to disperse their seeds, but the evolutionary drivers of this diversity remain poorly understood in most lineages. We tested the hypothesis that the evolution of wind dispersal traits within the melicgrasses (Poaceae: Meliceae Link ex Endl.) was correlated with occupation of open and disturbed habitats.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To evaluate wind dispersal potential, we collected seed dispersal structures (diaspores) from 24 melicgrass species and measured falling velocity and estimated dispersal distances. Species’ affinity for open and disturbed habitats were recorded using georeferenced occurrence records and land cover maps. To test whether habitat preference and dispersal traits were correlated, we used phylogenetically informed multilevel models.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Melicgrasses display several distinct morphologies associated with wind dispersal, suggesting likely convergence. Open habitat taxa had slower-falling diaspores, consistent with increased wind dispersal potential. However, their shorter stature meant that dispersal distances, at a given wind speed, were not higher than those of their forest-occupying relatives. Species with affinities for disturbed sites had slower-falling diaspores and greater wind dispersal distances, largely explained by lighter diaspores.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results are consistent with the hypothesized evolutionary relationship between habitat preference and dispersal strategy. However, phylogenetic inertia and other plant functions (e.g., water conservation) likely shaped dispersal trait evolution in melicgrasses. It remains unclear if dispersal trait changes were precipitated by or predated changing habitat preferences. Nevertheless, our study provides promising results and a framework for disentangling dispersal strategy evolution.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16406","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The wheat tribe, Triticeae, has been the subject of molecular phylogenetic analyses for nearly three decades, and extensive phylogenetic conflict has been apparent from the earliest comparisons among DNA-based data sets. While most previous analyses focused primarily on nuclear vs. chloroplast DNA conflict, the present analysis provides a broader picture of conflict among nuclear loci throughout the tribe.
Methods
Exon data were generated from over 1000 nuclear loci using targeted sequence capture with custom baits, and nearly complete chloroplast genome sequences were recovered. Phylogenetic conflict was assessed among the trees from the chloroplast genomes, the concatenated nuclear loci, and a series of nuclear-locus subsets guided by Hordeum chromosome gene maps.
Results
At the intergeneric level, the analyses collectively revealed a few broadly consistent relationships. However, the prevailing pattern was one of extensive phylogenetic conflict throughout the tribe, among both deep and shallow branches, and with the extent of the conflict varying among data subsets.
Conclusions
The results suggest continual introgression or lineage sorting within and among the named lineages of the Triticeae, shaping both deep and shallow relationships in the tribe.
近三十年来，小麦科（Triticeae）一直是分子系统发育分析的对象，而广泛的系统发育冲突从最早的基于 DNA 数据集的比较中就已显现出来。以前的大多数分析主要集中于核DNA与叶绿体DNA之间的冲突，而本分析则提供了一个更广阔的图景，说明了整个三叶草科的核基因位点之间的冲突。
{"title":"The phylogeny of the Triticeae: Resolution and phylogenetic conflict based on genomewide nuclear loci","authors":"Roberta J. Mason-Gamer, Dawson M. White","doi":"10.1002/ajb2.16404","DOIUrl":"10.1002/ajb2.16404","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The wheat tribe, Triticeae, has been the subject of molecular phylogenetic analyses for nearly three decades, and extensive phylogenetic conflict has been apparent from the earliest comparisons among DNA-based data sets. While most previous analyses focused primarily on nuclear vs. chloroplast DNA conflict, the present analysis provides a broader picture of conflict among nuclear loci throughout the tribe.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Exon data were generated from over 1000 nuclear loci using targeted sequence capture with custom baits, and nearly complete chloroplast genome sequences were recovered. Phylogenetic conflict was assessed among the trees from the chloroplast genomes, the concatenated nuclear loci, and a series of nuclear-locus subsets guided by <i>Hordeum</i> chromosome gene maps.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>At the intergeneric level, the analyses collectively revealed a few broadly consistent relationships. However, the prevailing pattern was one of extensive phylogenetic conflict throughout the tribe, among both deep and shallow branches, and with the extent of the conflict varying among data subsets.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The results suggest continual introgression or lineage sorting within and among the named lineages of the Triticeae, shaping both deep and shallow relationships in the tribe.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16404","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In plants, within-individual trait variation might result from mechanisms related to ontogenetic contingency, i.e., to the position of a particular structure within the plant, previous developmental events, and/or the developmental environment. Flower position within inflorescences as well as inflorescence position within plants can influence resource provisioning, phenology, biotic interactions, and reproductive success. Despite the potential implications of within-individual variation in plant reproductive phenotypes, its causes and effects on reproductive success are still little explored.
Methods
We assessed how reproductive success, in terms of fruit and seed set, and seed predation of 5883 flowers in Lathyrus vernus were influenced by their position within and among racemes, to what extent relationships between flower position and reproductive success and seed predation were mediated by phenology, and if positional effects on reproductive success depended on the external environment.
Results
In three years, basal flowers and racemes opened earlier and had higher fruit set than distal. Basal flowers also experienced higher seed predation. Differences among racemes in fruit and seed set were largely related to phenology, while differences in fruit set, seed set, and seed predation within racemes were not. In one year, differences in fruit set among flowers at different positions depended on flowering duration.
Conclusions
Our results highlight the important role of ontogenetic contingency for within-individual variation in phenology and reproductive success. As the spatial distribution of reproductive structures affects both within-plant trait distributions and fitness, it is a likely target for natural selection.
{"title":"Flower position within plants influences reproductive success both directly and via phenology","authors":"Alicia Valdés, Johan Ehrlén","doi":"10.1002/ajb2.16405","DOIUrl":"10.1002/ajb2.16405","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>In plants, within-individual trait variation might result from mechanisms related to ontogenetic contingency, i.e., to the position of a particular structure within the plant, previous developmental events, and/or the developmental environment. Flower position within inflorescences as well as inflorescence position within plants can influence resource provisioning, phenology, biotic interactions, and reproductive success. Despite the potential implications of within-individual variation in plant reproductive phenotypes, its causes and effects on reproductive success are still little explored.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We assessed how reproductive success, in terms of fruit and seed set, and seed predation of 5883 flowers in <i>Lathyrus vernus</i> were influenced by their position within and among racemes, to what extent relationships between flower position and reproductive success and seed predation were mediated by phenology, and if positional effects on reproductive success depended on the external environment.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In three years, basal flowers and racemes opened earlier and had higher fruit set than distal. Basal flowers also experienced higher seed predation. Differences among racemes in fruit and seed set were largely related to phenology, while differences in fruit set, seed set, and seed predation within racemes were not. In one year, differences in fruit set among flowers at different positions depended on flowering duration.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results highlight the important role of ontogenetic contingency for within-individual variation in phenology and reproductive success. As the spatial distribution of reproductive structures affects both within-plant trait distributions and fitness, it is a likely target for natural selection.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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