Plant Biology最新文献

Iron deficiency is a common nutritional disorder observed in calcareous soils, where its resolution by classical methods has shown its failure. However, the exploitation of certain potentialities possessed by crops (rhizosphere acidification, H-ATPase; Fe chelate reductase, FeCR, etc.), and the use of some biostimulants remains most efficient and sustainable approach. A greenhouse experiment was conducted on common bean plants subjected (FeD), or not (control, C) to Fe deficiency, or subjected to Fe deficiency and sprayed with 1 mM indole-3-acetic acid (FeD-IAA). The key physio-biochemical traits developed by plants in the different treatments, and their interrelationships were analysed. Iron deficiency induced specific Fe chlorosis, reduced chlorophyll and disrupted photosystem II performance. Plant growth and Fe concentration also significantly decreased, despite the stimulation of H-ATPase and FeCR activities. However, exogenous IAA application alleviated the adverse effects of FeD, particularly through promoted H-ATPase and FeCR activities, and Fe²⁺ concentration. The polar transport of IAA promoted root growth, H-ATPase and FeCR activities under FeD. The resulted Fe promotes chlorophyll biosynthesis and photosynthetic functioning. The calculated rhizosphere acidification capacity (RAC) and Fe chelate reductase capacity (FeCRC) are two useful traits for tolerant plant screening. The exogenous IAA application is a useful, efficient and eco-friendly approach for Fe-chlorosis alleviation. It promotes soil quality through the improvement of the soluble, plant-available form of iron.

European grassland plants are frequently attacked by root hemiparasites. However, little is known about host defence responses to parasitism. We investigated whether prior parasitization by a root hemiparasite makes hosts more susceptible to parasitism or, on the contrary, stimulates host defence against a future attack by hemiparasites. We grew three host species (Lolium perenne, Trifolium repens and Sanguisorba minor) in phase 1 for 3 months with the hemiparasite Rhinanthus alectorolophus, removed the parasite and grew the same host individuals in phase 2 with the hemiparasites R. alectorolophus or Melampyrum arvense. Previous infection by a parasite reduced the survival of the seedlings of Rhinanthus and Melampyrum with all host species but increased the biomass of the surviving parasites. A previous infection reduced the biomass of the hosts in most treatment combinations, but variation in initial host biomass at the start of phase 2 only partly explained this effect. Some of these interactions were specific to particular parasite-host species combinations. The results indicate that infection by root hemiparasites induces in the hosts defence mechanisms against future infection by the parasites (increased pre-attachment resistance), but parasite individuals that overcome this defence may then also be particularly good at exploiting the hosts (no increased post-attachment resistance). Thus, infection by root hemiparasites may activate host defence pathways that can influence future interactions with herbivores and pathogens and thus community dynamics.

Vessel length in xylem of woody species is a key functional trait for understanding water transport mechanisms, directly influencing xylem hydraulic efficiency and safety. However, the accurate measurements of vessel length are susceptible to methodological variations. This study employed silicone injection, air injection and pneumatic method on eight subtropical woody branches to compare their applicability, accuracy and limitations for measuring vessel length and its distribution pattern. The results demonstrated that the vessel length distribution curves in three methods all showed an asymmetric unimodal right-skewed distribution. Both mean and mode vessel lengths of eight species obtained from the pneumatic and air injection methods showed no significant differences and were all higher than that from the silicone injection method. Besides, across all vessel diameter ranges in eight species, both mean and mode vessel lengths showed significant positive correlations among the three methods. However, the correlations became weakened in wide vessel species, especially for the silicone injection data. Moreover, vessel lengths were significantly positively related to the vessel diameter in eight species. This study provides empirical evidence for selecting appropriate methods to measure vessel length, which has a crucial role in determining water transport functions in the xylem of plants.

Photoreceptors perceive light to assist plants to adapt to diurnal changes under varying environmental conditions. Among them, phytochromes act as photoreceptors for red or far-red light, regulating numerous developmental processes in plants; however, their roles in nutrient ion uptake remain largely unexplored. In this study, we investigated the effect of phytochrome A (phyA) deficiency on nutrient ion uptake and photosynthetic activity in wild-type (WT) plants and phyA-deficient mutants (phyA mutants) grown hydroponically, and productivity of mature plants in paddy fields in rice (Oryza sativa L.). We found that the uptake of various nutrient ions and photosynthetic CO₂ assimilation increased in phyA mutants grown hydroponically with abundant nutrients. Moreover, grain and shoot dry weights were improved in phyA mutants grown in a paddy field under doubled fertilizer amounts in comparison with the recommended doses for WT plants. Quantification of mineral nutrients in grains revealed no difference in mineral nutrient content between WT plants and phyA mutants, despite phyA mutants showing increased grain weight per plant. Taken together, these results indicate that phyA mutants possess favourable agronomic traits that enhance productivity through improved nutrient utilization.

Magnesium (Mg) leaching in acidic soils poses a significant challenge to sustainable agriculture. While nanotechnology offers potential solutions, the efficacy of magnesium oxide nanoparticles (MgO-NPs) in mitigating Mg loss remains poorly understood. This study investigated the effects of MgO-NPs on tomato growth and Mg migration in acidic soil using a soil column experiment, comparing them with conventional bulk MgO and MgSO₄. Our results demonstrated that MgO-NPs were the most effective treatment in reducing Mg leaching, showing a significantly lower Mg migration flux than MgSO₄ in tomatoes. Concurrently, MgO-NPs substantially increased exchangeable Mg content in the topsoil (0-20 cm) by over 113% and improved soil pH, thereby enhancing the retention of other key nutrients such as potassium and calcium. These improvements in the soil environment translated into enhanced plant performance: MgO-NPs significantly boosted chlorophyll content, photosynthetic efficiency, and mineral nutrient accumulation, which collectively led to increased plant growth and superior fruit yield and quality. In conclusion, MgO-NPs present a highly promising sustainable amendment for acidic soils, outperforming traditional Mg fertilizers by simultaneously minimizing nutrient leaching and promoting tomato productivity.

Distylous species have populations with two floral morphs bearing stigmas and anthers positioned reciprocally. This arrangement, assisted by the flower-pollinator fit, facilitates pollen deposition in different parts of pollinators' bodies, promoting outcrossing between morphs (i.e., legitimate pollen deposition - LPD). Typically, distyly occurs in one dimension (i.e., in height; 1D-heterostyly) but it can also appear as 3D-heterostyly, with stamens and styles bent and twisted. It is hypothesized that 3D-heterostyly improves reciprocity and LPD, reducing pollen loss compared to 1D-heterostyly. Variations in pollinator assemblages may lead to divergent selective pressures, resulting in different degrees of reciprocity and pollen flow patterns among populations of 1D- and 3D-heterostylous species. We tested these hypotheses in Linum tenue (1D-heterostyly) and L. suffruticosum (3D-heterostyly) using data on pollen deposition on stigmas, pollinators and reciprocity from six natural populations occupying contrasting environmental conditions in Spain. LPD was higher in L. suffruticosum than in L. tenue only when specialized pollinators predominated (Usia bee flies; Bombyliidae). Both pollinator frequency and the reciprocity of sex organs were associated with LPD in L. suffruticosum. In contrast, L. tenue showed consistently moderate LPD and high reciprocity across populations, despite variation in pollinator assemblages. However, frequent spontaneous self-pollination in L. tenue might reduce LPD on its stigmas. 3D-heterostyly appears more effective in specific pollination contexts but may be vulnerable to shifts in pollinator availability. In 1D-heterostylous populations, the independence of LPD from pollinator assemblage composition may explain the prevalence of 1D-heterostyly, although persistent spontaneous self-pollination in L. tenue could threaten the long-term maintenance of polymorphism.

Global change affects plant performance, both directly through warming and indirectly through changes in their biotic and abiotic surroundings. Soil microbes can critically influence plant performance, but are vulnerable to warming themselves. Disentangling direct effects of warming on plants from those intermediated by changes in microbial populations is complex under field conditions. To distinguish those effects, we monitored the performance of Agrostis capillaris and Anthoxanthum odoratum grown under uniform and controlled glasshouse conditions in soils inoculated with soil microbiomes conditioned by ambient, medium (14 years; MTW) or long-term (>55 years; LTW) geothermal warming. This was replicated under normal watering or drought conditions to additionally assess stress resistance. Furthermore, we analysed the microbiome of the inocula through metabarcoding to identify root-associated fungi and compare their relative abundance under different warming conditions. We found a decreased belowground biomass of both plant species when grown with LTW-conditioned microbiomes, with an exacerbated effect under drought for Ag. capillaris. We did not observe an associated increase in aboveground biomass, resulting in an increased aboveground biomass:belowground biomass ratio. These changes coincided with concurrent increases in the relative abundance of putative plant pathogens and arbuscular mycorrhizal fungi. We therefore conclude that soil microbes can mediate warming effects on plant performance through reduced belowground biomass.

Nonsense-mediated decay (NMD) is a crucial RNA surveillance mechanism that not only prevents synthesis of harmful truncated proteins but also keeps an eye on the quality and quantity check of mRNA in an efficient manner for effective gene expression. Viruses are in a continuous arm race with their host organisms to establish infection. Hence, hosts also constantly evolve new means of defence to exploit and suppress infection by the virus. In maximizing coding capacity in a small genome, several families of plant RNA viruses were documented to have NMD substrate features as a by-product. Although these features aid in viral infection, they are also susceptible to the host NMD pathway. In response, some viruses have evolved to bypass or disrupt the host NMD mechanism via cis-acting or trans-acting viral factors. By targeting the NMD pathway, it is possible to reduce the stability of pathogenic RNAs, leading to decreased pathogen viability and resistance. This review explores the mechanisms of NMD, its role in RNA quality control and the potential applications of manipulating NMD to combat pathogen resistance in agricultural and natural ecosystems. This review discusses the viral system circumventing the host NMD for their successful replication in plants. Moreover, an increased number of studies on the evasion mechanism of RNA viruses from host NMD provide insight into the molecular means of the NMD mechanism and may be linked to device defence strategies in agro-economic plants, which is an interesting future research possibility.

Short heat treatments are commonly used to estimate the leaf-level thermal tolerance of tree species. The effect of varying treatment duration has recently been challenged to have significant effects on the estimates of thermal tolerance thresholds and how it reflects the development of leaf necrosis. Here, we aim to elucidate the effect of treatment duration on the thermal tolerance estimates of three Mediterranean oak species. We applied heat treatments with varying treatment durations (15, 30, 60, 120 and 240 min) to excised leaves. The temperature response of the leaf maximum quantum yield of photosystem II (F_v/F_m) was measured immediately, 24 h, and 2 weeks after the treatment. Necrotic leaf damage was visually assessed 2 weeks after the treatment. Both the intensity of decline in F_v/F_m and the development of necrotic tissue due to longer heat treatments were described by a logistic function. The longer the heat treatment lasted, the lower was the required temperature to induce irreversible damage to the photosystems and to reach a certain degree of visible damage to the leaf tissue. F_v/F_m measurements carried out 24 h after the treatment predicted well the development of necrotic tissue. Leaf-level thermal tolerance of Mediterranean oak species depends largely on the exposure duration to heat. The heat duration response follows a predictable logarithmic relationship, which allows for modelling the potential heat damage during heatwaves and forecasting climate change responses of Mediterranean forests.

Flower size is a key determinant of reproductive success in animal-pollinated plants. However, traditional interpretations of these costs have often overlooked critical aspects of floral investment, including the complex relationships between flower size and factors such as initial resource allocation, floral longevity, resource resorption efficiency and ultimate reproductive output. We studied two Yulania species (Y. liliiflora and Y. soulangeana) to compare large and small flowers in terms of floral traits, pollinator preference, seed set ratio and nutrient resorption. Large flowers exhibited significantly greater floral display area, dry weight and pollen production but shorter longevity than small flowers. Pollinators, particularly bumblebees and honeybees, preferentially visited large flowers first, enhancing cross-pollination. When only large flowers were retained on branches (small flowers bagged), pollinator visitation frequency and seed set ratio of large flowers did not differ significantly from the natural control. In contrast, branches with only small flowers (large flowers bagged) experienced a significant reduction in pollinator visits. Consequently, the seed set ratio of small flowers in the absence of large flowers decreased significantly compared to that of small flowers under natural conditions. This suggests large flowers enhance pollinator attraction, indirectly benefiting neighbouring small flowers. Additionally, large flowers demonstrated significantly higher nutrient resorption efficiency (N, P, chlorophyll, starch, sugars and proteins) from senescing petals than small flowers. These findings indicate that large floral displays are not wasteful but instead optimize nutrient recycling and reproductive success. Floral size variation thus represents an adaptive strategy balancing pollinator-mediated reproduction with efficient resource use. Our study provides new insights into the ecological and evolutionary significance of floral trait variation in perennial plants.