Plant Ontogeny Research Articles

Effect of seed priming with auxin on ROS detoxification and carbohydrate metabolism and their relationship with germination and early seedling establishment in salt stressed maize

As crucial stages in the plant ontogeny, germination and seedling establishment under adverse conditions greatly determine staple crop growth and productivity. In the context of green technologies aiming to improve crop yield, seed priming is emerging as an effective approach to enhance seed vigor and germination performance under salt stress. In this study, we assess the efficiency of seed priming with indole-3-acetic acid (IAA) in mitigating the adverse effects of salt stress on maize (Zea mays L.) seedlings during germination and early seedling stages. In unprimed seeds, salt stress reduced germination indices, and seedling (both radicle and coleoptile) growth, together with decreased tissue hydration. However, seed priming using IAA significantly improved maize salt response, as reflected by the increased seed germination dynamics, early seedling establishment, and water status. Besides, seedlings from IAA-primed seeds showed a higher activity of α-amylase, resulting in increased sugar contents in roots and coleoptiles of salt-stressed plants. Further, IAA-seed priming stimulated the accumulation of endogenous IAA in salt-stressed seedlings, in concomitance with a significant effect on reactive oxygen species detoxification and lipid peroxidation prevention. Indeed, our data revealed increased antioxidant enzyme activities, differentially regulated in roots and coleoptiles, leading to increased activities of the antioxidant enzymes (SOD, CAT and GPX). In summary, data gained from this study further highlight the potential of IAA in modulating early interactions between multiple signaling pathways in the seed, endowing maize seedlings with enhanced potential and sustained tolerance to subsequent salt stress.

Interplay between drought and plant viruses co-infecting melon plants

Drought affects crops directly, and indirectly by affecting the activity of insect pests and the transmitted pathogens. Here, we established an experiment with well-watered or water-stressed melon plants, later single infected with either cucumber mosaic virus (CMV: non-persistent), or cucurbit aphid-borne yellow virus (CABYV: persistent), or both CMV and CABYV, and mock-inoculated control. We tested whether i) the relation between CMV and CABYV is additive, and ii) the relationship between water stress and virus infection is antagonistic, i.e., water stress primes plants for enhanced tolerance to virus infection. Water stress increased leaf greenness and temperature, and reduced leaf water potential, shoot biomass, stem dimensions, rate of flowering, CABYV symptom severity, and marketable fruit yield. Virus infection reduced leaf water potential transiently in single infected plants and persistently until harvest in double-infected plants. Double-virus infection caused the largest and synergistic reduction of marketable fruit yield. The relationship between water regime and virus treatment was additive in 12 out of 15 traits at harvest, with interactions for leaf water content, leaf:stem ratio, and fruit set. We conclude that both virus-virus relations in double infection and virus-drought relations cannot be generalized because they vary with virus, trait, and plant ontogeny.

Dynamics of SOD activity and accumulation of TBA-active products in the process of ontogeny of some sod-forming plants in a megalopolis

In the conditions of a modern metropolis, green spaces are an integral planning structure, which the issues of not only improving the aesthetics of the city's architecture, but also improving the environmental safety of the population are solved. Lawn grasses play a significant role in improving the microclimate of urban areas; the harmful concentration of gases in the air decreases, the regulation of the thermal regime and humidity is observed. Since almost half of the urban area is occupied by sod-forming plants, it is relevant to study the resistance of these species to anthropogenic impact in an urbanized environment. The aim of the work was to assess the state of the antioxidant system, namely the activity of superoxide dismutase (EC 1.15.1.11), and the accumulation of TBA-active products in the process of ontogeny of sod-forming plants growing in a metropolis. The objects of the study were Setaria viridis (L.) Beauv.) and Elytrígia répens (L.) Nevski.). It has been established that due to oxidative stress caused by vehicle emissions and industrial aeropollutants, there is an intensification of lipid peroxidation processes in the vegetative organs of Setaria viridis, Elytrigia repens during all phases of ontogeny. According to the results of the research, it was found that Elytrigia repens was more stable in terms of the content of TBA-active products (the level of the indicator in leaves was 30–50 %, roots – 20–44 % higher than the control indices) compared to Setaria viridis, for which the excess was 50–70 % (leaves) and 40–62 % (roots). SOD activity is an indicator of resilience to stressors and varies with the duration and intensity of stressors. The obtained results indicate that the enzyme activity of experimental plants in the generative state (increase in enzyme activity by 47.5–38 % in Elytrigia repens, by 74–62.5 % in Setaria viridis) in contaminated areas was higher than in virginile individuals (SOD activity levels: Elytrigia repens (37.5–26.5 %), Setaria viridis (60–50 %). The presence of close correlations between the activity of SOD and the content of TBA-active products characterizing the adaptive potential of plant organisms in the vegetative organs of the studied species was established.

A multiplex approach of MS, 1D-, and 2D-NMR metabolomics in plant ontogeny: A case study on Clusia minor L. organs (leaf, flower, fruit, and seed).

The genus Clusia L. is mostly recognised for the production of prenylated benzophenones and tocotrienol derivatives. The objective of this study was to map metabolome variation within Clusia minor organs at different developmental stages. In total 15 organs/stages (leaf, flower, fruit, and seed) were analysed by UPLC-MS and 1H- and heteronuclear multiple-bond correlation (HMBC)-NMR-based metabolomics. This work led to the assignment of 46 metabolites, belonging to organic acids(1), sugars(2) phenolic acids(1), flavonoids(3) prenylated xanthones(1) benzophenones(4) and tocotrienols(2). Multivariate data analyses explained the variability and classification of samples, highlighting chemical markers that discriminate each organ/stage. Leaves were found to be rich in 5-hydroxy-8-methyltocotrienol (8.5 μg/mg f.w.), while flowers were abundant in the polyprenylated benzophenone nemorosone with maximum level detected in the fully mature flower bud (43 μg/mg f.w.). Nemorosone and 5-hydroxy tocotrienoloic acid were isolated from FL6 for full structural characterisation. This is the first report of the NMR assignments of 5-hydroxy tocotrienoloic acid, and its maximum level was detected in the mature fruit at 50 μg/mg f.w. Seeds as typical storage organ were rich in sugars and omega-6 fatty acids. To the best of our knowledge, this is the first report on a comparative 1D-/2D-NMR approach to assess compositional differences in ontogeny studies compared with LC-MS exemplified by Clusia organs. Results derived from this study provide better understanding of the stages at which maximal production of natural compounds occur and elucidate in which developmental stages the enzymes responsible for the production of such metabolites are preferentially expressed.

Potassium transporter KUP9 regulates plant response to K+ deficiency and affects carbohydrate allocation in A.thaliana

Due to the essential roles of K+ in plants, its up to 10% share in plant dry matter, and its mostly low availability in soil, effective potassium management poses a significant challenge for the plant. To enable efficient uptake and allocation of K+, numerous transporters and channels have evolved. During the last two decades, efforts have been made to characterise these transport proteins in Arabidopsis thaliana using knock-out mutants. Several KT/HAK/KUP transporters have been assigned specific functions. In this work, we contribute to an understanding of the role of AtKUP9 in plant adaptation to low K+ availability. We found that in vitro, atkup9 has reduced lateral root growth under low-K conditions, and root apical meristem proliferation is reduced in lateral roots compared with the primary root. We also documented AtKUP9 expression in both roots and shoots and showed that AtKUP9 expression is modulated during plant ontogeny and as a result of K+ deprivation. Altered carbohydrate allocation was also documented in atkup9. Mutants exported more soluble saccharides from leaves under K+ rich conditions and, under K+ deficiency, atkup9 accumulated more soluble saccharides in the shoots. A possible role of AtKUP9 in these processes is discussed.

Diameter explains transient allocation of non-photosynthetic organs in trees

A central issue in plant ecology is exploring universal rules and the mechanisms under which photosynthetic energies are allocated to different organ parts. Until recently, prevalent studies focused on testing either optimal allocation theory or allometric allocation theory in predicting plant biomass partitioning patterns. However, paying much attention to the stable state prevents the development of new biomass allocation theories in transient time scales. Here, based on theories in transients and the allometric relationships in plant traits, I develop general theoretical models to study the transient perturbations of plant biomass allocated to non-photosynthetic organ parts. With both simulation and empirical approaches, I investigate the effect of plant stem diameter at breast height (DBH) on the variation of biomass allocation patterns during plant ontogeny. Results show that increases in DBH can mitigate the magnitude of the perturbations of plant biomass and biomass fractions allocated to both plant stem and root parts. The findings are robust when either deterministic or stochastic models are conducted. Moreover, empirical analyses from a large forest database in Eurasia consistently support the predictions from the theoretical frameworks. In this paper, I draw attention to the transient allocation pattern of plant biomass for non-photosynthetic organs, and I find the significant role of DBH. This work has important implications in both theoretical breakthroughs and practical applications. It not only provides the foundation to test new biomass allocation hypotheses but also directs agricultural and forest management to achieve stabilized yields.

Intergenerational consequences of an auxin-like herbicide on plant sensitivity to a graminicide mediated by a fungal endophyte

In agroecosystems, herbicides are the predominant anthropogenic selection pressure for agriculture weed species. While weeds are the primary target, herbicides can have adverse impacts on non-target plant beneficial microorganisms. We aimed to investigate the influence of a foliar endophytic fungus (Epichloë occultans) on the sensitivity of Lolium multiflorum to a graminicide herbicide (diclofop-methyl) during both plant ontogeny and progeny. Susceptible individuals to diclofop-methyl with and without endophyte were pre-exposed to the auxin 2,4-D herbicide. This herbicide is known to stimulate the metabolic detoxification mechanism (CYP-450) of diclofop-methyl. Regardless of the endophyte, 2,4-D pre-treatment increased mother plant survival to nearly 100 % under diclofop treatment but not in the progeny. Furthermore, maternal plant exposure to 2,4-D reduced endophyte transmission to the seeds and from seed-to-seedlings. Our findings suggest that, despite a reduction in diclofop-methyl sensitivity during the ontogeny of mother plants, 2,4-D-mediated induction of likely CYP-450 metabolism is not intergenerationally transmitted and shows detrimental effects on the symbiotic endophyte persistence.

Counteracting effects of soil biota on emergence and growth of herbaceous plants

BackgroundPlants condition the biotic composition of their rhizosphere. In turn, this plant legacy on the soil biota may affect the performance of plants recruiting in their vicinity. Unravelling how plant-soil legacies drive plant recruitment is key to understand vegetation dynamics and plant community assembly. Studies on the topic usually focus on the effects of soil microbiota as a whole, while the relative role of different guilds of soil organisms in the plant recruitment processes is not usually dissected.AimsHere, we used soils of Mediterranean woody plant species to test whether arbuscular mycorrhizal fungi (AMF) and small-size microbiota (< 50 µm) (MB) affect the germination success and growth of eight herbaceous plants.ResultsWe documented a significant increase in seedling emergence probability when small-sized MB was present and no effect of AMF. In contrast, the aboveground plant biomass decreased with the presence of MB and increased with that of AMF. Interestingly, those plants growing in the absence of MB and in soils from woody plants associated with higher AMF richness developed higher aboveground biomass.ConclusionThis study brings new evidence on how soil microbial communities can determine the performance of their associated herb community, and also, how the effects of different microbial guilds may change across the plant ontogeny. Given these results, the differential effect of soil microbial functional guilds should be considered to better understand plant soil legacies and feedbacks, potentially driving plant recruitment and community assembly.

Enhancers are genes that express organizational RNAs

A longstanding enigma in molecular biology is the lack of scaling of protein-coding genes with developmental complexity, referred to as the g-value paradox. On the other hand, a feature of the evolution of multicellular organisms is the emergence of genetic loci termed “enhancers,” which control the spatiotemporal patterns of gene expression during development. Enhancer action has been widely interpreted in terms of an early model that postulated that transcription factors bound at enhancers are brought into juxtaposition with the promoters of target genes. This model tacitly assumed that there is no trans-acting gene product of enhancers, but subsequent studies have shown that enhancers are transcribed in the cells in which they are active. Like protein-coding genes, enhancers produce short bidirectional transcripts and long alternatively spliced RNAs, albeit at lower levels due to their transitory and cell-specific regulatory functions. The evidence indicates that long noncoding RNAs (lncRNAs) expressed from enhancers (elncRNAs) guide the formation of phase-separated transcriptional hubs and the epigenetic modifications to direct cell fate decisions during animal and plant ontogeny. Many, and likely most, lncRNAs are elncRNAs, which should be recognized as a bona fide class of gene products alongside mRNAs, rRNAs, tRNAs, snoRNAs, miRNAs and others of established function, with sequences specifying elncRNAs comprising an increasing fraction of genomic information as developmental complexity increases.

Experimental Growth Conditions affect Direct and Indirect Defences in two Cotton Species

Cotton has been used as a model plant to study direct and indirect plant defence against herbivorous insects. However, the plant growing conditions could have an important effect on the outcome of such plant defence studies. We examined how common experimental growth conditions influence constitutive and inducible defences in two species of cotton, Gossypium hirsutum and G. herbaceum. We induced plants by applying caterpillar regurgitant to mechanical wounds to compare the induction levels between plants of both species grown in greenhouse or phytotron conditions. For this we measured defence metabolites (gossypol and heliocides) and performance of Spodoptera frugiperda caterpillars on different leaves, the emission of plant volatiles, and their attractiveness to parasitic wasps. Induction increased the levels of defence metabolites, which in turn decreased the performance of S. frugiperda larvae. Constitutive and induced defence levels were the highest in plants grown in the phytotron (compared to greenhouse plants), G. hirsutum and young leaves. Defence induction was more pronounced in plants grown in the phytotron and in young leaves. Also, the differences between growing conditions were more evident for metabolites in the youngest leaves, indicating an interaction with plant ontogeny. The composition of emitted volatiles was different between plants from the two growth conditions, with greenhouse-grown plants showing more variation than phytotron-grown plants. Also, G. hirsutum released higher amounts of volatiles and attracted more parasitic wasps than G. herbaceum. Overall, these results highlight the importance of experimental abiotic factors in plant defence induction and ontogeny of defences. We therefore suggest careful consideration in selecting the appropriate experimental growing conditions for studies on plant defences.

ФОРМУВАННЯ ПРОДУКТИВНОСТІ КВАСОЛІ ЗВИЧАЙНОЇ ЗАЛЕЖНО ВІД СОРТІВ, ІНОКУЛЯЦІЇ ТА УДОБРЕННЯ

Ріст і розвиток рослин квасолі прямо залежить від умов навколишнього середовища, основними складниками якого є температура повітря та ґрунту, освітленість, вологість, мінеральне живлення. Продуктивність рослин зумовлюється наявністю цих факторів, і чим більше вони відповідають біологічним особливостям культури, тим повніше реалізуються потенційні можливості сортів квасолі. Під час дослідження насіння квасолі звичайної перед сівбою обробляли різними штамами мікроорганізмів. Залежно від цього дещо змінювалися міжфазні періоди росту й розвитку рослин. Тривалість періоду «сівба – повна стиглість» у рослин квасолі сорту Ластівка, інокульованих різними штамами Rhizobium phaseoli, у середньому за період дослідження 2020–2022 рр. відрізнялася на 1–3 доби.

Comprehensive screening and categorization of selected okra germplatm lines against shoot and fruit borer (Earias vittella) tolerance during plant ontogeny

Comprehensive screening and categorization of selected okra germplatm lines against shoot and fruit borer (Earias vittella) tolerance during plant ontogeny

Physiological and Biochemical Characteristics and Response Patterns of Salinity Stress Responsive Genes (SSRGs) in Wild Quinoa (Chenopodium quinoa L.)

Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils. Quinoa, a protein-comprehensive cereal in the plant kingdom, is an exceptional crop in terms of salt stress tolerance level. It seems an excellent model for the exploration of salt-tolerance mechanisms and cultivation of salt-tolerant germplasms. In this study, the seeds and seedlings of the quinoa cultivar Shelly were treated with different concentrations of NaCl solution. The physiological, biochemical characteristics and agronomic traits were investigated, and the response patterns of three salt stress-responsive genes (SSRGs) in quinoa were determined by real-time PCR. The optimum level of stress tolerance of quinoa cultivar Shelly was found in the range of 250–350 mM concentration of NaCl. Salt stress significantly induced expression of superoxide dismutase (SOD), peroxidase (POD), and particularly betaine aldehyde dehydrogenase (BADH). BADH was discovered to be more sensitive to salt stress and played an important role in the salt stress tolerance of quinoa seedlings, particularly at high NaCl concentrations, as it displayed upregulation until 24 h under 100 mM salt treatment. Moreover, it showed upregulation until 12 h under 250 mM salt stress. Taken together, these results suggest that BADH played an essential role in the salt-tolerance mechanism of quinoa. Based on the expression level and prompt response induced by NaCl, we suggest that the BADH can be considered as a molecular marker for screening salt-tolerant quinoa germplasm at the early stages of crop development. Salt treatment at different plant ontogeny or at different concentrations had a significant impact on quinoa growth. Therefore, an appropriate treatment approach needs to be chosen rationally in the process of screening salt-tolerant quinoa germplasm, which is useful to the utilization of saline soils. Our study provides a fundamental information to deepen knowledge of the salt tolerance mechanism of quinoa for the development of salt-tolerant germplasm in crop breeding programs.

PECULIARITIES OF ONTOGENY OF HERACLEUM MANTEGAZZIANUM SOMMIER &amp; LEVIER. ON THE TERRITORY OF KAMENETZ REGION

The article deals with the peculiarities of the ontogeny of plants of the Heracleum mantegazzianum Sommier &amp; Levier species. The sequence of the ontogenetic cycle of plants is analyzed and characterized. The age spectra of H. mantegazzianum populations in the Kamianets region were studied. To study the ontogenetic structure of populations, 5 experimental plots of10 m2 were laid out. It was established that the ontogeny of H. mantegazzianum is represented by6 ontogenetic states: seedlings (p), juveniles (j), imatures (im), virgin (v), generative (g) and senescents (s). According to the ontogenetic structure, the cenopopulations of all plots are characterized as normal, full-membered. The maximum of the age spectrum falls on seedlings (73,7%, site 3). The age spectrum of all studied populations was determined as left-handed, probably due to the high seed productivity of the species. The average population density for each study site was determined. The analysis showed that the average density varies from 12 to 17 individuals per 1 m2. The highest number of plants was observed in plots 3 and 5, while in other plots the ratio of the number of plants is relatively the same.

Size- and environment-driven seedling survival and growth are mediated by leaf functional traits.

Ecologists usually find that plant demography (e.g. survival and growth) changes along with plant size and environmental gradients, which suggests the effects of ontogeny-related processes and abiotic filtering. However, the role of functional traits underlying the size– and environment–demography relationships is usually overlooked. By measuring individual-level leaf traits of more than 2700 seedlings in a temperate forest, we evaluated how seedling traits mediated the size– and environment–demography relationships. We found leaves were larger for taller seedlings; leaf economics traits were more conservative in taller seedlings and under high-light and low-elevation conditions. Structural equation modelling showed that a higher survival probability for taller seedlings was indirectly driven by their larger leaf area. Although taller seedlings had lower growth rates, larger and more resource-conservative leaves could promote the growth of these tall seedlings. Environmental variables did not influence seedling survival and growth directly but did influence growth indirectly by mediating trait variation. Finally, species-specific variation in traits along with size and environments was associated with the species-specific variation in seedling survival and growth. Our study suggests that not only plant ontogeny- and environment-related ecological processes, but functional traits are also important intermediary agents underlying plant size– and environment–demography relationships.

Plant characteristics drive ontogenetic changes in herbivory damage in a temperate forest

Abstract Understanding ontogenetic differences in plant defenses and herbivory damage is crucial for obtaining a better understanding of plant life‐history strategies, community assembly, and dynamics. Although many studies have compared plant defenses or herbivory damage between ontogenetic stages (e.g. sapling vs. adult), how the effects of plant characteristics on leaf herbivory damage change during plant ontogeny has rarely been examined across species or in a species‐rich natural community. To elucidate the effects of plant characteristics, we compared the relationships of leaf herbivory by insects with stem density, plant size, and leaf traits between saplings and adults for almost all co‐occurring woody species (56 species, ranging from rare to abundant) in a Japanese temperate forest. In most species, adults were larger, fewer in number, and had leaf traits that were potentially less favorable to herbivores (e.g. stronger, or with more phenolics). In contrast, we observed species‐specific directions of changes in herbivory damage between adults and saplings with plant phylogeny or density having no clear effect. The relationships between some plant traits and herbivory damage were ontogeny dependent, indicating a shift from chemical to physical defense as plants mature, although most of the species characteristics studied were highly correlated between stages. Such ontogeny‐dependent relationships between plant traits and herbivory damage could cause variation in the ontogenetic changes in herbivory damage among species depending on the value of plant traits. Moreover, the direction and magnitude of the effects of ontogenetic differences in species traits on the ontogenetic differences in herbivory damage varied depending on the traits. Together, these factors could have caused the observed ontogenetic changes in herbivory damage among species. Synthesis. Our study demonstrated how relationships between plant characteristics and herbivory damage can change ontogenetically across many coexisting woody species in a forest community, suggesting that plant traits may perform different functions related to herbivory at different ontogenetic stages. This has rarely been considered in previous dualistic comparisons of individual traits and herbivory damage between ontogenetic stages, and it is vital for understanding plant life‐history strategies across stages in relationships with herbivores in natural communities.

Spatial phylogenetic and phenotypic patterns reveal ontogenetic shifts in ecological processes of plant community assembly

The analysis of the spatial phylogenetic and phenotypic structure of plant communities can provide insight into the underlying processes and interactions governing their assembly, and how these may change during plant ontogeny. We used point pattern analysis to find out if saplings and adult plants are surrounded by phylogenetically and phenotypically more similar or more dissimilar neighbours than expected by chance, and whether these associations change from the sapling to the adult stage. To this end, we combined information on the phylogenetic structure and eight phenotypic traits of 15 woody plant species in two Mediterranean mixed forests of southeastern Spain. At the community level, we found that the sapling bank at both sites did not show phylogenetic or phenotypic spatial patterns, but adults showed phylogenetic clustering (i.e. heterospecific neighbours were more similar than expected). At the species level, we found frequently repulsive patterns in the sapling bank of less abundant species (i.e. heterospecific sapling or adult neighbours were more dissimilar than expected) in both, phylogenetic and phenotypic analyses. For the adult stage, we found phylogenetic attraction (i.e. more similar neighbours) in just one species and phenotypic clustering in four species. The processes driving the assembly of the communities of saplings and adults leave detectable signals in the spatial phylogenetic and phenotypic structure of our two forest communities. Our findings reinforce the existence of ontogenetic shifts in the mechanisms involved in plant community assembly. Facilitation between phylogenetically distant and phenotypically divergent species favours the recruitment of less abundant species. However, processes acting later in the ontogeny ameliorate the competition between close relatives and determine the spatial structure of adult plants. Nevertheless, the role of phenotype in shaping the interactions between adult plants was context‐ and trait‐dependent. The use of spatial point pattern analysis allowed a nuanced interpretation of the phylogenetic and phenotypic structures of plant communities.

How seeds and growth dynamics influence plant size and yield: Integrating trait relationships into ontogeny

Abstract Seeds, growth rates and duration of growth influence plant development. However, we lack a mechanistic understanding of how they lead to larger and higher‐yielding plants, as these traits have not yet been explicitly studied in combination and across ontogeny. Seed size and growth dynamics have evolved differently during domestication and improvement. Nevertheless, it remains unclear whether the relationships between these traits and their contribution to plant size and yield have also changed over the course of crop evolution. Here we grew wild, landrace and improved accessions of 18 annual herbaceous crops in a glasshouse. For each plant, we measured seed mass, growth rate and duration of vegetative growth. We also measured plant size at three ontogenetic stages: seedling, juvenile and mature, and reproductive output. Using path analyses, we tested causal relationships between the traits and quantified their relative importance in determining mature plant size and yield. Seed mass and duration of vegetative growth were more important than growth rates in explaining variations in mature plant size and yield among species. Domesticated plants were larger, had heavier seeds and higher yields, but did not grow faster or for longer time‐spans than their wild progenitors. Trait relationships did not differ between the wild, landrace and improved accessions. Our results suggest that annual herbs reach larger sizes primarily through a combination of heavier seeds and longer vegetative growth periods. Moreover, domestication has increased plant size only through the heavy‐seed causal pathway, via cascading effects during ontogeny. However, the high yields of modern crops hardly be explained by the traits considered here, suggesting the importance of other drivers, such as roots and their microbiome. Synthesis. We provide a better mechanistic understanding of the size axis of global plant trait variation and emphasise the role of growth duration in explaining the diversity of mature plant sizes. Seeds and growth dynamics are highly functionally coordinated with plant size, and this coordination has changed little during crop evolution. Our results highlight that multi‐trait relationships throughout plant ontogeny play a key role in governing how domestication has influenced plant size and crop yields.

Growth and nutrient accumulation metrics of Diodia saponariifolia plants as a potential native cover crop in southeastern Brazil

Competition for resources between crops and weeds hinders the increase of production in agroecosystems. The trait-based plant species selection of cover crops can be a useful tool to suppress competing plants in addition to providing environmental services. Here, we assessed the growth and macronutrient accumulation metrics in Diodia saponariifolia (Rubiaceae) plants, a native cover crop found in family farming systems in southeastern Brazil. Under greenhouse conditions, three viable D. saponariifolia cuttings were planted per tray. The experimental design was entirely randomized, with treatments consisting of plant sampling times, at regular intervals of 7 days between 16 and 93 days after transplanting (DAT) and 15 days between 93 and 138 DAT. Based on dry mass and chemical analysis of leaves, stems, and roots; we fitted the logistic model to explore the metrics of growth and macronutrient accumulation. Overall, the increment in plant dry mass was slow about halfway through the experimental period, being subsequently replaced by a phase of rapid growth. The stem was the plant fraction with the highest relative biomass accumulation. The total macronutrient concentration followed the descending order of K > N > Ca > Mg > P, varying along the plant ontogeny. Considering the nutrient content, the estimated 200 g m−2 of aboveground dry mass, and 0.3 m2 of leaf area, it is suggested to perform the first mechanical weeding along the third month of growth. Our results suggest that D. saponariifolia has satisfactory agronomical features for its establishment as a cover crop in different agricultural contexts.

Intriguing Role of Proline in Redox Potential Conferring High Temperature Stress Tolerance.

Proline is a proteinogenic amino acid synthesized from glutamate and ornithine. Pyrroline-5-carboxylate synthetase and pyrroline-5-carboxylate reductase are the two key enzymes involved in proline synthesis from glutamate. On the other hand, ornithine-δ-aminotransferase converts ornithine to pyrroline 5-carboxylate (P5C), an intermediate in the synthesis of proline as well as glutamate. Both proline dehydrogenase and P5C dehydrogenase convert proline back to glutamate. Proline accumulation is widespread in response to environmental challenges such as high temperatures, and it is known to defend plants against unpropitious situations promoting plant growth and flowering. While proline accumulation is positively correlated with heat stress tolerance in some crops, it has detrimental consequences in others. Although it has been established that proline is a key osmolyte, its exact physiological function during heat stress and plant ontogeny remains unknown. Emerging evidence pointed out its role as an overriding molecule in alleviating high temperature stress (HTS) by quenching singlet oxygen and superoxide radicals. Proline cycle acts as a shuttle and the redox couple (NAD+/NADH, NADP+/NADPH) appears to be highly crucial for energy transfer among different cellular compartments during plant development, exposure to HTS conditions and also during the recovery of stress. In this review, the progress made in recent years regarding its involvement in heat stress tolerance is highlighted.