amined in an easy-pick and a hard-pick line of Tabasco peppers. The anatomical parameters examined included: sclereid development, size and shape of parenchyma cells, volume of intercellular space, and crystal development across the diameter of the separation zone. During ripening, sclerification proceeded centripetally in both lines but was more pronounced in the hard pick line. Parenchyma cells in the central zone of both lines were nearly isodiametric and did not enlarge significantly during fruit maturation. In the peripheral zone, parenchyma cells of easy-pick fruits elongated significantly more than corresponding cells in the hard-pick line. There was a greater volume of intercellular space in the central zone than the peripheral zone of both lines, but more so in the easy-pick line. The number of crystals in the central zone decreased in both lines during fruit ripening. This study suggests that several anatomical factors are associated with ease of fruit separation from the peduncle in pepper.
{"title":"Anatomy of fruit detachment in tabasco pepper (Capsicum frutescens, Solanaceae)","authors":"M. Sundberg, C. Motsenbocker, Yeuhe Huang","doi":"10.2307/3557541","DOIUrl":"https://doi.org/10.2307/3557541","url":null,"abstract":"amined in an easy-pick and a hard-pick line of Tabasco peppers. The anatomical parameters examined included: sclereid development, size and shape of parenchyma cells, volume of intercellular space, and crystal development across the diameter of the separation zone. During ripening, sclerification proceeded centripetally in both lines but was more pronounced in the hard pick line. Parenchyma cells in the central zone of both lines were nearly isodiametric and did not enlarge significantly during fruit maturation. In the peripheral zone, parenchyma cells of easy-pick fruits elongated significantly more than corresponding cells in the hard-pick line. There was a greater volume of intercellular space in the central zone than the peripheral zone of both lines, but more so in the easy-pick line. The number of crystals in the central zone decreased in both lines during fruit ripening. This study suggests that several anatomical factors are associated with ease of fruit separation from the peduncle in pepper.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557541","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
COLLINS, BEVERLY (Savannah River Ecology Laboratory, Aiken, SC 29802). Ground layer competition and herbivory effects on cherrybark oak (Quercus pagoda Raf.) regeneration in experimental canopy gaps. J. Torrey Bot. Soc. 130:147-157. 2003. -Windthrows and small-scale forest harvests generate environmental heterogeneity and dense regrowth. In such sites, interactions among environmental factors, competition with ground layer vegetation, and herbivores attracted to the disturbed area all potentially influence recruitment and early establishment of canopy tree species. I examined the interactive effects of overstory gap size, canopy openness, herb layer competition, and mammalian (deer, swamp rabbits) herbivory on emergence and seedling bank formation of cherrybark oak, Quercus pagoda Raf., in experimental gaps created by mechanized logging in a bottomland hardwood forest. Acorns were planted in exclosures (deer, swamp rabbits, deer + swamp rabbits, neither) in the center of three gaps of each of six gap sizes (7, 10, 14, 20, 29, 40 m radius) and outside the exclosures in center, edge, and forest positions. Mortality was greatest during recruitment (within the first season), and was due primarily to damage to acorns by seed predators and shade effects on seedling establishment. After three seasons, seedlings from damaged acorns in the exclosure plots were shorter than those from undamaged acorns; however, these seedlings had higher relative growth rate, which suggests that acorn damage effects decline over time. Herb layer competition and shade due to position within a gap or gap size were associated with reduced survival or height of seedlings, both in the exclosures and in center, edge, and forest positions. Deer or rabbit herbivory had no measurable effect on seedling survival or growth over the first three seasons. Natural or created canopy gaps ' 14 m radius can be foci for Q. pagoda regeneration if acorns are protected from predators; however, the dense vegetation in regenerating gaps could limit seedling height growth and multiple openings may be necessary for ascent out of the seedling bank.
{"title":"Ground layer competition and herbivory effects on cherrybark oak (Quercus pagoda Raf.) regeneration in experimental canopy gaps1","authors":"B. Collins","doi":"10.2307/3557550","DOIUrl":"https://doi.org/10.2307/3557550","url":null,"abstract":"COLLINS, BEVERLY (Savannah River Ecology Laboratory, Aiken, SC 29802). Ground layer competition and herbivory effects on cherrybark oak (Quercus pagoda Raf.) regeneration in experimental canopy gaps. J. Torrey Bot. Soc. 130:147-157. 2003. -Windthrows and small-scale forest harvests generate environmental heterogeneity and dense regrowth. In such sites, interactions among environmental factors, competition with ground layer vegetation, and herbivores attracted to the disturbed area all potentially influence recruitment and early establishment of canopy tree species. I examined the interactive effects of overstory gap size, canopy openness, herb layer competition, and mammalian (deer, swamp rabbits) herbivory on emergence and seedling bank formation of cherrybark oak, Quercus pagoda Raf., in experimental gaps created by mechanized logging in a bottomland hardwood forest. Acorns were planted in exclosures (deer, swamp rabbits, deer + swamp rabbits, neither) in the center of three gaps of each of six gap sizes (7, 10, 14, 20, 29, 40 m radius) and outside the exclosures in center, edge, and forest positions. Mortality was greatest during recruitment (within the first season), and was due primarily to damage to acorns by seed predators and shade effects on seedling establishment. After three seasons, seedlings from damaged acorns in the exclosure plots were shorter than those from undamaged acorns; however, these seedlings had higher relative growth rate, which suggests that acorn damage effects decline over time. Herb layer competition and shade due to position within a gap or gap size were associated with reduced survival or height of seedlings, both in the exclosures and in center, edge, and forest positions. Deer or rabbit herbivory had no measurable effect on seedling survival or growth over the first three seasons. Natural or created canopy gaps ' 14 m radius can be foci for Q. pagoda regeneration if acorns are protected from predators; however, the dense vegetation in regenerating gaps could limit seedling height growth and multiple openings may be necessary for ascent out of the seedling bank.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557550","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Romano, J. Morton, G. Romano, R. Latham, J. Morton
GUSTAFSON, D. J. (Department of Biology, University of Pennsylvania, Philadelphia, PA 19104), G. ROMANO (Morphotek, Inc., 210 Welsh Pool Rd., Exton, PA 19341), R. E. LATHAM (Continental Conservation, P.O. Box 57, Rose Valley, PA 19086), AND J. K. MORTON (Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1 Canada). Amplified fragment length polymorphism analysis of genetic relationships among the serpentine barrens endemic Cerastium velutinum Rafinesque var. villosissimum Pennell (Caryophyllaceae) and closely related Cerastium species. J. Torrey Bot. Soc 130:218-223. 2003.-Amplified fragment length polymorphism (AFLP) banding patterns were used to examine the genetic relationships among the long-haired barrens chickweed (Cerastium velutinum var. villosissimum), members of the Cerastium arvense complex, and Cerastium species native to Europe. Cerastium velutinum var. villosissimum is genetically similar to the widespread C. velutinum and this association clustered with C. arvense spp. strictum and C. viride. Cerastium fontanum, C. glomeratum, and C. tomentosum, species native to Europe, were distinct from the North American group. Cerastium velutinum var. villosissimum is globally endangered, is genetically more similar to C. velutinum than other members of the North American C. arvense complex and is deserving of conservation efforts.
GUSTAFSON, D. J.(宾夕法尼亚大学生物系，费城，宾夕法尼亚州19104)，G. ROMANO (Morphotek, Inc.， 210 Welsh Pool Rd, Exton，宾夕法尼亚州19341)，R. E. LATHAM(大陆保护，玫瑰谷，宾夕法尼亚州19086邮政信箱57号)和J. K. MORTON(滑铁卢大学生物系，滑铁卢，ON, N2L 3G1加拿大)。蛇形无毛苔特有品种绒心苔(Cerastium velutinum Rafinesque var. villosissimum Pennell)与近缘种Cerastium亲缘关系的扩增片段长度多态性分析。托里·博特。Soc 130:218 - 223。2003.-利用扩增片段长度多态性(AFLP)条带模式，研究了长毛无毛雏茅(Cerastium velutinum var. villlosissimum)、Cerastium arvense复合体成员和欧洲原产Cerastium物种之间的遗传关系。绒毛Cerastium velutinum var. villlosissimum在遗传上与广泛分布的绒毛Cerastium velutinum相似，并与C. arvense spp. strictum和C. viride聚集在一起。原产于欧洲的Cerastium fontanum、C. glomeratum和C. tomentosum与北美群体不同。Cerastium velutinum var. villosissimum是全球濒危物种，与北美C. arvense复合体的其他成员相比，在遗传上与C. velutinum更相似，值得保护。
{"title":"Amplified fragment length polymorphism analysis of genetic relationships among the serpentine barrens endemic Cerastium velutinum Rafinesque var. villosissimum Pennell (Caryophyllaceae) and closely related Cerastium species1","authors":"G. Romano, J. Morton, G. Romano, R. Latham, J. Morton","doi":"10.2307/3557556","DOIUrl":"https://doi.org/10.2307/3557556","url":null,"abstract":"GUSTAFSON, D. J. (Department of Biology, University of Pennsylvania, Philadelphia, PA 19104), G. ROMANO (Morphotek, Inc., 210 Welsh Pool Rd., Exton, PA 19341), R. E. LATHAM (Continental Conservation, P.O. Box 57, Rose Valley, PA 19086), AND J. K. MORTON (Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1 Canada). Amplified fragment length polymorphism analysis of genetic relationships among the serpentine barrens endemic Cerastium velutinum Rafinesque var. villosissimum Pennell (Caryophyllaceae) and closely related Cerastium species. J. Torrey Bot. Soc 130:218-223. 2003.-Amplified fragment length polymorphism (AFLP) banding patterns were used to examine the genetic relationships among the long-haired barrens chickweed (Cerastium velutinum var. villosissimum), members of the Cerastium arvense complex, and Cerastium species native to Europe. Cerastium velutinum var. villosissimum is genetically similar to the widespread C. velutinum and this association clustered with C. arvense spp. strictum and C. viride. Cerastium fontanum, C. glomeratum, and C. tomentosum, species native to Europe, were distinct from the North American group. Cerastium velutinum var. villosissimum is globally endangered, is genetically more similar to C. velutinum than other members of the North American C. arvense complex and is deserving of conservation efforts.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557556","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In seed predation experiments, ragweed seeds were selected less often than those of four other early successional species: pigweed (Amaranthus retroflexus), bluegrass (Poa annua), common lamb's quarters (Chenopodium album), and goldenrod (Solidago altissima). Moreover, fire ants selected both larger and smaller seeds than those of ragweed indicating that selection was not driven by relative seed size. There was an increase in the number of ragweed seeds removed by fire ants as the summer progressed, suggesting that more ragweed seeds were incorporated into the diet of fire ants as other species of seeds became less abundant. Lastly, nearly all seeds of pigweed (a preferred species) placed 1, 2, 3 and 4 meters from ant mounds were consumed, which suggests that fire ants may effectively forage the entire field. Both fire ants and ragweed are early successional species that rapidly invade disturbed areas created by humans and natural events. Fire ants significantly contributed to the success of ragweed plants growing in an old field community.
{"title":"Influence of mound building and selective seed predation by the red imported fire ant (Solenopsis invicta) on an old-field plant assemblage","authors":"Renee Seaman, P. Marino","doi":"10.2307/3557553","DOIUrl":"https://doi.org/10.2307/3557553","url":null,"abstract":"In seed predation experiments, ragweed seeds were selected less often than those of four other early successional species: pigweed (Amaranthus retroflexus), bluegrass (Poa annua), common lamb's quarters (Chenopodium album), and goldenrod (Solidago altissima). Moreover, fire ants selected both larger and smaller seeds than those of ragweed indicating that selection was not driven by relative seed size. There was an increase in the number of ragweed seeds removed by fire ants as the summer progressed, suggesting that more ragweed seeds were incorporated into the diet of fire ants as other species of seeds became less abundant. Lastly, nearly all seeds of pigweed (a preferred species) placed 1, 2, 3 and 4 meters from ant mounds were consumed, which suggests that fire ants may effectively forage the entire field. Both fire ants and ragweed are early successional species that rapidly invade disturbed areas created by humans and natural events. Fire ants significantly contributed to the success of ragweed plants growing in an old field community.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557553","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
and 24 pairs on the north side of the range. For each plot we measured slope, plot aspect, soil pH and soil nutrients, the importance value for trees, within-plot frequency for shrubs and recorded presence/absence for herbaceous taxa. Soil on basalt had a higher pH and was richer in nutrients, particularly exchangeable Ca and Mg than soil on arkose. Principal Components Analysis of plots using soil variables indicated that those associated with bedrock accounted for 51% of the variance while soil differences related to aspect accounted for 22%. The multi-response permutation procedure indicated significant differences in distribution in all vegetation layers with respect to both bedrock and aspect. Species richness on basalt was significantly higher for both trees and herbaceous plants, and was also higher on the south side of the range for herbaceous plants. Of the 89 species present in more than 5% of the plots, 32% had significantly different distributions with respect to bedrock alone, 21% differed significantly with respect to both bedrock type and aspect while only 9% differed significantly with aspect independent of bedrock. The largest differences were in the herbaceous layer. Canonical correspondence analysis using soil and site variables indicated that for all vegetation layers the strongest gradient was related to bedrock.
{"title":"Influence of bedrock and aspect on soils and plant distribution in the Holyoke Range, Massachusetts","authors":"K. Searcy, B. Wilson, J. Fownes","doi":"10.2307/3557551","DOIUrl":"https://doi.org/10.2307/3557551","url":null,"abstract":"and 24 pairs on the north side of the range. For each plot we measured slope, plot aspect, soil pH and soil nutrients, the importance value for trees, within-plot frequency for shrubs and recorded presence/absence for herbaceous taxa. Soil on basalt had a higher pH and was richer in nutrients, particularly exchangeable Ca and Mg than soil on arkose. Principal Components Analysis of plots using soil variables indicated that those associated with bedrock accounted for 51% of the variance while soil differences related to aspect accounted for 22%. The multi-response permutation procedure indicated significant differences in distribution in all vegetation layers with respect to both bedrock and aspect. Species richness on basalt was significantly higher for both trees and herbaceous plants, and was also higher on the south side of the range for herbaceous plants. Of the 89 species present in more than 5% of the plots, 32% had significantly different distributions with respect to bedrock alone, 21% differed significantly with respect to both bedrock type and aspect while only 9% differed significantly with aspect independent of bedrock. The largest differences were in the herbaceous layer. Canonical correspondence analysis using soil and site variables indicated that for all vegetation layers the strongest gradient was related to bedrock.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557551","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
each area of the fen), and recorded the number of pomes on each fruiting stem. Two-thirds of all chokeberries occurred in the early successional habitat. Black chokeberry dominated both areas, comprising 72% of all chokeberry stems in the early successional area, and 79% in the forested area. Few pomes were observed in the forested area, and no red chokeberries fruited there. In the early successsional area, nearly equal percentages of each species produced fruit (8% of red chokeberries, and 10% of black chokeberries). However, red chokeberry produced significantly more pomes per stem, as well as 20% more pomes than black chokeberry, across the
{"title":"The distribution and fruiting of red and black chokeberry (Aronia arbutifolia and A. melanocarpa) in a southern Appalachian fen1","authors":"I. M. Rossell, Jenna M. Kesgen","doi":"10.2307/3557554","DOIUrl":"https://doi.org/10.2307/3557554","url":null,"abstract":"each area of the fen), and recorded the number of pomes on each fruiting stem. Two-thirds of all chokeberries occurred in the early successional habitat. Black chokeberry dominated both areas, comprising 72% of all chokeberry stems in the early successional area, and 79% in the forested area. Few pomes were observed in the forested area, and no red chokeberries fruited there. In the early successsional area, nearly equal percentages of each species produced fruit (8% of red chokeberries, and 10% of black chokeberries). However, red chokeberry produced significantly more pomes per stem, as well as 20% more pomes than black chokeberry, across the","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557554","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
fenses. We evaluated the association between herbivory and the amount of azoxyglycosides in the Cycadales using phylogenetic independent contrasts. We hypothesized that herbivory types should be related to the presence of macrozamin and cycasin, thus herbivory should be lower in species with higher concentrations of azoxyglycosides. We gathered information available on the literature of these two characters as well as life form, geographic distribution, height, and seed volume for the majority of cycad species, in order to assess correlated evolution and control for possible allometric effects. Herbivory types and macrozamin were negatively correlated, suggesting a possible defensive function for macrozamin against herbivores. No significant correlation was observed between cycasin percent and herbivory type. However, when analysed using phylogenetic independent contrasts and thus removing the historical effect, the association did not hold. This suggests that the presence of metabolites in plants may have evolved for some other reason, and has been mantained among cycads perhaps by phylogenetic inertia. The presence of macrozamin should then be explained as an exaptation, playing today an important role in defense against herbivores. Furthermore, this analysis showed that macrozamin has independently and repeatedly (Bowenia, Macrozamia, Stangeria) increased over evolutionary time.
{"title":"The role of macrozamin and cycasin in cycads (Cycadales) as antiherbivore defenses1","authors":"C. Castillo-Guevara, V. Rico‐Gray","doi":"10.2307/3557555","DOIUrl":"https://doi.org/10.2307/3557555","url":null,"abstract":"fenses. We evaluated the association between herbivory and the amount of azoxyglycosides in the Cycadales using phylogenetic independent contrasts. We hypothesized that herbivory types should be related to the presence of macrozamin and cycasin, thus herbivory should be lower in species with higher concentrations of azoxyglycosides. We gathered information available on the literature of these two characters as well as life form, geographic distribution, height, and seed volume for the majority of cycad species, in order to assess correlated evolution and control for possible allometric effects. Herbivory types and macrozamin were negatively correlated, suggesting a possible defensive function for macrozamin against herbivores. No significant correlation was observed between cycasin percent and herbivory type. However, when analysed using phylogenetic independent contrasts and thus removing the historical effect, the association did not hold. This suggests that the presence of metabolites in plants may have evolved for some other reason, and has been mantained among cycads perhaps by phylogenetic inertia. The presence of macrozamin should then be explained as an exaptation, playing today an important role in defense against herbivores. Furthermore, this analysis showed that macrozamin has independently and repeatedly (Bowenia, Macrozamia, Stangeria) increased over evolutionary time.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557555","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SCHNEIDER, E. L AND S. CARLQUIST (Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105). Unusual pit membrane remnants in perforation plates of Cyrillaceae. J. Torrey Bot Soc. 130: 225-230. 2003-Pit membrane remnants occur in all collections of Cyrillaceae studied: they are minimal in Cliftonia monophylla, C. parviflora, and Purdiaea antillana, whereas in the specimen of Cyrilla racemiflora, many perforations possess intact pit membranes or membranes with small pores or, in a few cases, large holes. Some perforation pit membranes in C. racemiflora appear to possess holes only in one of the two pit membranes of the two adjacent cells. Retention of pit membrane remnants in C. racemiflora may represent a tendency to lose conductive capability related to the habitat (understory, marshy ground) This could be considered a stage in vessel loss except for the fact that three other criteria for vessel loss are not met. Presence of pit membrane remnants in Cyrillaceae is consistent with such presence in the sister family Clethraceae as well as in other families of Ericales (Theales of some authors) as defined on the basis of recent molecular data.
{"title":"Unusual pit membrane remnants in perforation plates of Cyrillaceae","authors":"E. Schneider, S. Carlquist","doi":"10.2307/3557540","DOIUrl":"https://doi.org/10.2307/3557540","url":null,"abstract":"SCHNEIDER, E. L AND S. CARLQUIST (Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105). Unusual pit membrane remnants in perforation plates of Cyrillaceae. J. Torrey Bot Soc. 130: 225-230. 2003-Pit membrane remnants occur in all collections of Cyrillaceae studied: they are minimal in Cliftonia monophylla, C. parviflora, and Purdiaea antillana, whereas in the specimen of Cyrilla racemiflora, many perforations possess intact pit membranes or membranes with small pores or, in a few cases, large holes. Some perforation pit membranes in C. racemiflora appear to possess holes only in one of the two pit membranes of the two adjacent cells. Retention of pit membrane remnants in C. racemiflora may represent a tendency to lose conductive capability related to the habitat (understory, marshy ground) This could be considered a stage in vessel loss except for the fact that three other criteria for vessel loss are not met. Presence of pit membrane remnants in Cyrillaceae is consistent with such presence in the sister family Clethraceae as well as in other families of Ericales (Theales of some authors) as defined on the basis of recent molecular data.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557540","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TAFT, J. B. (Center for Biodiversity, Illinois Natural History Survey, Champaign, IL 61820). Fire effects on community structure, composition, and diversity in a dry sandstone barrens. J. Torrey Bot. Soc. 130:170-192. 2003. Fire effects on canopy, shrub/sapling, and ground-cover species composition, structure, and diversity patterns were examined following two burns in a dry sandstone barrens remnant in southern Illinois. Vegetation was monitored at a fire treatment site and a nearby fire-free control site for three years following the first fire and two years following the second fire. Fire effects were most pronounced in the ground-cover stratum and least in the tree stratum. At the fire treatment site, tree species richness was unchanged while tree density (stems 26 cm dbh) declined 10.6% from a baseline total of 945 stems/ha to 845 stems/ha. There was additional tree mortality the second growing season following each fire. Quercus stellata remained by far the most dominant species. Fire effects were limited to small-diameter trees ('15 cm dbh) while total tree basal area increased at the treatment site from 17.8 m2/ha to 18.22 m2. Stem density in the shrub/sapling stratum significantly declined immediately following each fire while recovery to preburn levels was underway in four years just prior to the second burn. After two burns, stem density was about 45% the baseline amount. In the ground-cover stratum there were significant increases in diversity, species richness, species density, and percent cover at the fire treatment site while at the control site these variables remained unchanged or slightly declined. Noteworthy differences occurred among C3 and C4 graminoid species as many C3 species (e.g., Dichanthelium spp., Carex spp.) increased greatly in frequency and percent cover with fire while C4 species (e.g., Schizachyrium scoparium, Sorghastrum nutans) had parallel decline in the treatment and control sites.
塔夫脱，j.b.(生物多样性中心，伊利诺伊州自然历史调查，香槟，伊利诺伊州61820)。火灾对干旱砂岩荒地群落结构、组成和多样性的影响。托里·博特。Soc。130:170 - 192。2003. 在伊利诺斯州南部的一个干燥的砂岩荒地遗迹中，研究了两次燃烧对冠层、灌木/树苗和地被物种组成、结构和多样性的影响。在第一次火灾后和第二次火灾后分别对一个火灾处理场和附近一个无火控制点的植被进行了三年和两年的监测。火灾效应在地被层中最明显，在乔木层中最小。在火灾处理场地，树种丰富度没有变化，但树木密度(干26 cm dbh)从基线的945株/ha下降到845株/ha，下降了10.6%。在每次火灾后的第二个生长季节，树木死亡率增加。到目前为止，星栎仍然是最占优势的物种。火灾效应仅限于小直径树木(15 cm dbh)，而处理场地的树木基材面积从17.8 m2/ha增加到18.22 m2。灌木/幼树层的茎密度在每次火灾发生后立即显著下降，而在第二次火灾发生前的4年内恢复到燃烧前的水平。两次烧伤后，茎密度约为基线量的45%。地表覆盖层的多样性、物种丰富度、物种密度和盖度在火灾处理场地均有显著增加，而在对照场地这些变量基本不变或略有下降。C3和C4禾草类植物之间存在显著差异，许多C3禾草类植物(如双香草属、Carex属)的被火频率和被火覆盖百分比显著增加，而C4禾草类植物(如荆芥属、高粱属)的处理和对照位点呈平行下降趋势。
{"title":"Fire effects on community structure, composition, and diversity in a dry sandstone barrens","authors":"J. B. Taft","doi":"10.2307/3557552","DOIUrl":"https://doi.org/10.2307/3557552","url":null,"abstract":"TAFT, J. B. (Center for Biodiversity, Illinois Natural History Survey, Champaign, IL 61820). Fire effects on community structure, composition, and diversity in a dry sandstone barrens. J. Torrey Bot. Soc. 130:170-192. 2003. Fire effects on canopy, shrub/sapling, and ground-cover species composition, structure, and diversity patterns were examined following two burns in a dry sandstone barrens remnant in southern Illinois. Vegetation was monitored at a fire treatment site and a nearby fire-free control site for three years following the first fire and two years following the second fire. Fire effects were most pronounced in the ground-cover stratum and least in the tree stratum. At the fire treatment site, tree species richness was unchanged while tree density (stems 26 cm dbh) declined 10.6% from a baseline total of 945 stems/ha to 845 stems/ha. There was additional tree mortality the second growing season following each fire. Quercus stellata remained by far the most dominant species. Fire effects were limited to small-diameter trees ('15 cm dbh) while total tree basal area increased at the treatment site from 17.8 m2/ha to 18.22 m2. Stem density in the shrub/sapling stratum significantly declined immediately following each fire while recovery to preburn levels was underway in four years just prior to the second burn. After two burns, stem density was about 45% the baseline amount. In the ground-cover stratum there were significant increases in diversity, species richness, species density, and percent cover at the fire treatment site while at the control site these variables remained unchanged or slightly declined. Noteworthy differences occurred among C3 and C4 graminoid species as many C3 species (e.g., Dichanthelium spp., Carex spp.) increased greatly in frequency and percent cover with fire while C4 species (e.g., Schizachyrium scoparium, Sorghastrum nutans) had parallel decline in the treatment and control sites.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3557552","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68722625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Noteworthy plants reported from the Torrey Range - 2001.","authors":"E. Lamont, Stephen M. Young","doi":"10.2307/3088707","DOIUrl":"https://doi.org/10.2307/3088707","url":null,"abstract":"","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088707","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68729760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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