Plant Biology最新文献

The evolutionary limits to generalization in plant pollination systems are often determined by trade-offs in which adaptations to one set of flower visitors reduces the effectiveness of another set of visitors. A key question is whether flowers can be pollinated equally effectively during the day and the night, given that the attractants for diurnal visitors are expected to be very different to those for nocturnal visitors. To address this question, we investigated the pollination system of the mass-flowering desert geophyte Nerine laticoma (Amaryllidaceae) over 2 years. We measured floral traits, including colour, scent, dimensions, floral rewards, visitation and reproductive traits. Finally, we exposed a subset of flowers exclusively to either diurnal or nocturnal visitors to establish their relative contributions to reproduction. Nerine laticoma has relatively open flowers, with exposed nectar, attracting a wide diversity of pollinators, including bees, butterflies, nocturnal settling moths and hawkmoths. We established that N. laticoma is reliant on pollinators for seed production. Flowers exposed only during the day set a similar number of seeds to those exposed only during the night, indicating that the plant is effectively pollinated by both diurnal and nocturnal animals. The results highlight the importance of multiple pollinators and their contribution to reproductive success in desert environments with variable pollinator communities. The contribution of all possible pollinators in a system, including frequently overlooked nocturnal visitors, should thus be taken into account.

Specific generation of reactive oxygen species (ROS) is important for signalling and defence in many organisms. In plants, different types of ROS serve useful biological functions in the extracellular space (apoplast), influencing polymer structures as well as signalling during immune responses. The current knowledge of apoplastic ROS dynamics is limited, as dynamic monitoring of extracellular redox processes in vivo remains difficult. We employed evolutionary distant land plant model species from bryophytes and flowering plants to test whether the genetically encoded redox biosensor roGFP2-Orp1 can be used to assess extracellular redox dynamics. Secreted roGFP2-Orp1 can provide information about local diffusion barriers and protein cysteinyl oxidation rate in the apoplast, after pre-reduction. Observed re-oxidation rates were slow - within the range of hours. Compared to Physcomitrium patens, re-oxidation in Arabidopsis thaliana was faster and increased after triggering an immune response. Comparing roGFP2-Orp1 signals in tip-growing P. patens protonema and Nicotiana tabacum pollen tubes, we consistently find no intracellular redox gradient, but a partially reduced extracellular sensor in pollen tubes. Our data indicate differences in extracellular oxidative processes between species and within a species, depending on cell type and immune signalling.

Trans-acting small interfering RNA (tasiRNAs) are a special type of endogenous small RNAs (sRNAs) found only in plants. Their biogenesis requires an initial miRNA-mediated cleavage of RNA precursors transcribed from TAS genes. TasiRNAs act in trans to silence gene expression by cleaving mRNAs with sequences partially complementary to their own. While Arabidopsis thaliana contains several TAS genes not found in other plants, the miR390-TAS3-ARF pathway is highly conserved among land plant lineages. This pathway exerts its function by silencing a subgroup of Auxin Response Factor (ARF) genes; these tasiRNAs are termed tasiR-ARFs. Many downstream auxin signals are mediated by ARFs acting as transcription factors to confer sensitivity and robustness to the hormone responses in diverse development contexts. These pathway functions are critical for plant growth, developmental timing, and correct organ patterning, such as leaf morphology and polarity, lateral root architecture, and flowering, as well as coping with stress. The phenotypes caused by mutations affecting tasiR-ARF production vary across plant species, showing pleiotropic effects, suggesting a co-opted process where the tasiR-ARF pathway evolution occurred to serve different functions, depending on plant developmental cues. One way to unify the diverse roles of this pathway would be through auxin response integration, possibly by exploring the evolution of ARF3 transcription factors and downstream genes. In this review, we discuss versatility of the tasiR-ARF pathway in land plants according to known developmental and environmental responses where the phytohormone auxin plays an essential role.

Application of iron oxide nanoparticles (NP) (Fe₃O₄-NPs) in plant biotechnology presents new opportunities for enhancing metabolic activity of medicinal plants; however, their specific effects on Melissa officinalis subsp. officinalis remain poorly understood. This study examined effects of Fe₃O₄-NPs at 0, 25, 50, 75, and 100 mg L^-1 on morphological traits, phenolic compound accumulation, antioxidant activity, enzyme inhibition, and expression of PAL, TAT and RAS genes under in vitro conditions. Seeds were germinated on Murashige & Skoog medium and cultured for 30 days. Morphological characteristics were measured, total phenolics and flavonoid content were quantified spectrophotometrically, and phenolic profiles determined via HPLC. Antioxidant activity (CUPRAC, DPPH, ABTS), enzyme inhibition (AChE, MAO-A, urease), and gene expression (qRT-PCR) were also assessed. Treatment at 25 mg L^-1 yielded the highest content of total phenolics (41.68 mg GAEg^-1 plant) and rosmarinic acid (22.10 μg mg^-1 DW), together with improved antioxidant, MAO-A (2.95 mg plant mL^-1) and urease (6.71 mg plant mL^-1) inhibition activity. Higher concentrations (75-100 mg L^-1) increased AChE inhibition but reduced antioxidant capacity. PAL, TAT, and RAS expression was upregulated in all treated groups: PAL peaked at 25 mg L^-1, RAS at 100 mg L^-1, and TAT at 75 mg L^-1. There was no direct correlation between gene expression and phenolic levels, suggesting involvement of post-transcriptional or alternative regulatory mechanisms. These results demonstrate that Fe₃O₄-NPs act as dose-dependent modulators of secondary metabolism and bioactivity in M. officinalis, offering promising tools for nanoparticle-based elicitation strategies in medicinal plant biotechnology.

Tropical forests across the globe are facing intensifying droughts, yet their responses are far from uniform. We argue that this variability should be understood in the context of interacting legacies across scales. At the continental scale, evolutionary history and past climatic filters have left distinct imprints on forest composition. At landscape scale, edaphic and hydrological heterogeneity constrain species distributions and functional strategies. These legacies converge in the functional trait space available to tree communities, shaping their resilience or vulnerability to novel drought regimes. By placing drought in this biogeographic, edaphic, and trait-based context, we highlight the importance of integrating historical and environmental filters into predictive models of tropical forest futures.

Leaf anatomy is a key factor determining plant ecology. Cell size and number are related to leaf size in tracheophytes, but this has been little studied in bryophytes, which never reach large leaf sizes. We studied the main anatomical factors determining leaf size in mosses, and how this is related to their ecology. We measured cell and leaf dimensions in 287 moss species, as well as cell density, cell wall thickness and midrib length. These measurements were contrasted against different traits, highlighting growth form and genome size, and correlations among traits. Moss leaf size was positively correlated with cell size but negatively correlated with cell density. The longest moss leaves were always supported by midribs reaching or surpassing the leaf apex. Genome size was positively correlated with cell and, especially, leaf size. All these relationships were stronger in acrocarpous mosses. Leaf size in mosses is limited by the mechanical support provided by cell turgor and the midrib. Both mechanical support and effect of genome size were more important in acrocarpous mosses. Our findings suggest anatomy as a key linking factor between genome size and plant ecology.

Cyphomandra betacea, a valuable understory crop in southwestern China, exhibits high sensitivity to water availability. Under global climate change with increasingly erratic precipitation, understanding how Cyphomandra betacea, seedlings respond to rainfall variations is crucial for sustaining this distinctive industry. Through controlled experiments, this work systematically investigates how different rainfall patterns affect seedling growth and physiology, providing a theoretical basis for science-based management under future climate scenarios. Seedlings were subjected to a four-month simulated rainfall experiment with two rainfall intervals (T: 3-day; T₊: 6-day) and three rainfall amounts (W: control; W₊: +40%; W_-: -40%). Biomass, non-structural carbohydrates (NSC), and carbon, nitrogen, phosphorus stoichiometric characteristics were analysed. Seedling growth is more sensitive to variations in rainfall amount, and appropriate increases in rainfall can promote seedling growth and development. Under changes in rainfall patterns, seedlings prioritize the storage of NSC in stems, followed by leaves, with the lowest allocation to roots. Nitrogen content within organs is pivotal for the composition of NSC and can regulate the sugar-starch conversion process. The July W₊T treatment resulted in optimal performance for the majority of growth indicators and demonstrated the highest nutrient accumulation efficiency. We identified a stem-preferential carbon allocation strategy and systemic N limitation, offering key insights for conservation and cultivation under changing climates.

Space is considered one of the harshest environments for living organisms, where ionizing radiation poses a significant threat to biological systems. Although plants exhibit higher resistance to radiation than animals, their photosynthetic machinery remains highly vulnerable. Given the role of plants in Controlled Ecological Life Support Systems (CELSSs), understanding how environment influences plant performance is critical for space missions. This study investigated the combined effects of X-ray irradiation (0.3, 10, or 20 Gy) and light quality (white, red, or red-blue LEDs) on young Vigna radiata L. plants. To assess plant potential acclimation strategies to radiation, we evaluated key functional traits, focusing on growth and photosynthetic performance. Specifically, we quantified in vivo chlorophyll fluorescence, photosynthetic pigments (chlorophylls, carotenoids), and expression of two major photosynthetic proteins: D1 (PSII core) and Rubisco. To our knowledge, no previous studies have explored how specific light wavelengths modulate plant responses to ionizing radiation during early development stages. Our results showed that red light enhances biomass allocation to shoots, promotes pigment accumulation, specifically at 0.3 and 10 Gy, and maintains higher photochemical efficiency and protein expression even at the highest radiation dose, compared to other light wavelengths. Maintaining an appropriate light environment during initial phases of growth enhances photosynthetic performance, reducing the harmful effects of X-rays, thus enabling plants to fulfil their ecological role in CELSSs.

Soybean (Glycine max), is an important oilseed crop that plays a vital role in ensuring global food security. However, it is susceptible to multiple abiotic stresses that can reduce yield. The ubiquitination-proteasome pathway is a crucial regulatory mechanism that controls a broad range of processes in plants. We investigated the function of Glycine max drought-induced SINA (GmDIS1), an E3 ligase gene, in soybean abiotic stress tolerance using Agrobacterium-mediated transformation to develop soybean GmDIS1-RNAi transgenic lines. GmDIS1 was significantly induced under drought and heat stress. Several physiological traits revealed resilience of GmDIS1-RNAi lines under drought and heat stress. The functions of stress-related genes, such as AOS and GmPAL were investigated to dissect the pathways that contribute to drought and heat tolerance in GmDIS1-RNAi lines. The results suggest that decreasing expression of GmDIS1 can enhance soybean tolerance to drought and heat, and also provide a significant target for developing more drought- and heat-tolerant soybean varieties and other crops.

Mediterranean temporary ponds (MTPs) are dynamic habitats where low levels of dissolved oxygen can significantly impact plant life. This study investigated the effect of hypoxia and near-anoxia on seed germination and the induction of secondary dormancy in 14 plant species, characteristic of this habitat. Imbibed seeds were subjected to various oxygen concentrations (0.1, 5, 10, or 21% O₂), in both light and darkness. We also tested seed ability to recover germination by moving them to aerobic conditions. We measured embryo growth after hypoxic treatments and during recovery in three species with morpho-physiological dormancy, a rarely investigated response in this dormancy class. Our findings revealed a wide range of species-specific responses. Hypoxia did not inhibit germination in half of the tested species in the light, while near-anoxia completely inhibited germination in all species. However, most seeds fully recovered germination ability once aerobic conditions were restored. Interestingly, hypoxia in darkness reduced or prevented germination in some species and specifically induced secondary dormancy in Juncus bufonius. Surprisingly, seeds of Bulliarda vaillantii lost their light requirement for germination under hypoxia. In three Ranunculus species with morpho-physiological dormancy, hypoxia slowed embryo growth, which delayed germination recovery. This study reveals that MTPs species have evolved adaptations, ranging from tolerance to hypoxic conditions, to the ability to trigger secondary dormancy, which are crucial to surviving and reproducing in these unique environments. The results offer new insights into the germination ecophysiology of MTPs species and their regeneration niche in temporary wetlands.