Response Of Seeds Research Articles

The effects of Marrubium alysson and Torilis arvensis natural and nano extracts on priming of wheat seeds in response to drought

AbstractAgriculture and climate change are inextricably linked in various aspects. Droughts have become more frequent as a result of climate change, having a significant impact on crop productivity. As a result, the current study investigated the effect of seed priming with natural plant extract and biosynthesized nano plant extract as an environmentally friendly tool for mitigating the drought effect on wheat as an economic crop. The study investigates the biosynthesis of Ag-nano particles from extracts of Marrubium alysson and Torilis arvensis. The UV–Vis spectrophotometer was used to characterize the biosynthesized AgNPs. Wheat grains were primed with Marrubium alysson and Torilis arvensis, along with their nanoextracts, and grown in different water regimes (100%, 60% and 40% field capacity), as well as hydropriming. Leaves were collected to determine the photosynthetic pigments, phenolics, flavonoids, CAT, GPX, H2O2, MDA, soluble sugars, and soluble proteins. In comparison with hydropriming seeds, the study discovered that natural and nano extracts significantly increased the CAT and GPX, as well as soluble proteins. Phenolics, flavonoids, soluble sugars, H2O2, and MDA content all decreased significantly, but pigment content remained unchanged. The study believed that priming wheat with natural and nano extracts, improved drought tolerance through the use of their metabolites, which included soluble sugars, phenolics, and flavonoids, accumulating in other metabolites like lignin, starch, and flavolignan to increase plant tolerance and reduce oxidative damage. Furthermore, nano extracts of Torilis arvensis and Marrubium alysson may be more effective than plant extracts since they separate from each other in PCA analysis.

Germination of Senegalia mellifera seeds in response to presowing treatments

This study aimed to evaluate the size of Senegalia mellifera seeds and determine the most effective scarification techniques to improve germination. The experiment, conducted at Botswana University of Agriculture and Natural Resources, involved ten presowing treatments, including control, nicking, soaking in sulphuric acid for different durations, and boiling water for varying periods. A completely randomized design (CRD) was used for the experiment. Germination data was transformed using arcsine to meet normal distribution requirements and then analyzed using analysis of variance (ANOVA). The results showed that the presowing treatments had a statistically significant effect on germination (P<0.00001). Seeds treated with sulphuric acid, nicking, and those left untreated exhibited the highest germination rates, while seeds treated with boiling water showed the lowest germination percentages. These findings indicate that the seed coats of S. mellifera are permeable to water and air, and presowing treatments do not show any significant effect on the successful germination of S. mellifera seed.

Transcription factor DIVARICATA1 positively modulates seed germination in response to salinity stress.

Seed germination is a critical checkpoint for plant growth under unfavorable environmental conditions. In Arabidopsis (Arabidopsis thaliana), the abscisic acid (ABA) and gibberellic acid (GA) signaling pathways play important roles in modulating seed germination. However, the molecular links between salinity stress and ABA/GA signaling are not well understood. Herein, we showed that the expression of DIVARICATA1 (DIV1), which encodes a MYB-like transcription factor, was induced by GA and repressed by ABA, salinity, and osmotic stress in germinating seeds. DIV1 positively regulated seed germination in response to salinity stress by directly regulating the expression of DELAY OF GERMINATION 1-LIKE 3 (DOGL3) and GA-STIMULATED ARABIDOPSIS 4 (GASA4) and indirectly regulating the expression of several germination-associated genes. Moreover, NUCLEAR FACTOR-YC9 (NF-YC9) directly repressed the expression of DIV1 in germinating seeds in response to salinity stress. These results help reveal the function of the NF-YC9-DIV1 module and provide insights into the regulation of ABA and GA signaling in response to salinity stress during seed germination in Arabidopsis.

Germination Kinetics of Ferula communis L. Seeds, a Potentially Multipurpose-Use Wild Species

Despite exhibiting intriguing features associated with its multipurpose applications and drought tolerance, Ferula communis remains a wild and uncultivated species, with limited experimental research on its biology, starting from seed germination and extending to its ecology. The purpose of this study was to investigate potential germination and kinetics in F. communis seeds in response to four cold stratification periods (0, 15, 45, and 90 days at a constant temperature of 5 °C) and four temperatures (5, 10, 15, and 20 °C) under continuous darkness. F. communis exhibited a pronounced germination potential exceeding 90%, with the optimal temperature for germination falling within the range of 5 °C to 15 °C, without necessitating cold stratification. A dramatic drop of the germination percentage was observed at 20 °C (<10%), suggesting a form of conditional dormancy attributed to the higher temperature tested.

Effect of cadmium and lead on the morphology and protein profile of Calligonum comosum seeds

BackgroundSoils contaminated with heavy metals (HMs) pose a risk to human health via the food chain, as many edible plants absorb these metals. In turn, some of these plants could be used as phytoremediators for such soils. Calligonum comosum is an indigenous medicinal shrub that grows naturally in wide swaths of sandy soil in Saudi Arabia and has many advantages that render it a promising candidate for the treatment of HM-contaminated areas. But the impact of HM on this plant remains unknown, especially in the early stages of its development.ObjectiveThis investigation aimed to study the effects of lead (Pb) and cadmium (Cd) on the germination of C. comosum seeds under laboratory conditions, and assess the seeds’ response to these metals.MethodsThe C. comosum seed germination was monitored in Petri dishes containing Pb and Cd at increasing concentrations (25, 50, 75, and 100 µM) for up to 3 weeks. SDS-PAGE was used to examine the protein profile of germinated seeds and the western blot was used to assess the influence of HMs on the activities of the catalase enzyme and the beta subunit of ATP synthase (AtpB).ResultsThe germination rate and speed of C. comosum seeds were delayed by increasing concentrations of either Pb or Cd, but this effect was dose-dependent. SDS-PAGE analysis results revealed that exposure to both metals led to altered protein profiles as indicated by the resulting band intensities and disappearance of some proteins compared with the untreated controls. Further, the western blot analysis detected greater activity of catalase enzyme as well as AtpB in the Cd- and Pb-treated seeds.ConclusionC. comosum seeds treated with Cd or Pb enhance protein degradation and denaturation beside oxidative stress, leading to reduced seed viability. These results suggest oxidoreduction proteins and those involved in ATP synthesis are enhanced in C. comosum seeds in response to Cd and Pb stressors, which is a probable mechanism by which seeds may tolerate heavy metal stress.

Spatial specificity of metabolism regulation of abscisic acid-imposed seed germination inhibition in Korean pine (Pinus koraiensis sieb et zucc).

Abscisic acid (ABA) can negatively regulate seed germination, but the mechanisms of ABA-mediated metabolism modulation are not well understood. Moreover, it remains unclear whether metabolic pathways vary with the different tissue parts of the embryo, such as the radicle, hypocotyl and cotyledon. In this report, we performed the first comprehensive metabolome analysis of the radicle and hypocotyl + cotyledon in Pinus koraiensis seeds in response to ABA treatment during germination. Metabolome profiling showed that following ABA treatment, 67 significantly differentially accumulated metabolites in the embryo were closely associated with pyrimidine metabolism, phenylalanine metabolism, cysteine and methionine metabolism, galactose metabolism, terpenoid backbone biosynthesis, and glutathione metabolism. Meanwhile, 62 metabolites in the hypocotyl + cotyledon were primarily involved in glycerophospholipid metabolism and glycolysis/gluconeogenesis. We can conclude that ABA may inhibit Korean pine seed germination primarily by disrupting the biosynthesis of certain plant hormones mediated by cysteine and methionine metabolism and terpenoid backbone biosynthesis, as well as reducing the reactive oxygen species scavenging ability regulated by glutathione metabolism and shikimate pathway in radicle. ABA may strongly disrupt the structure and function of cellular membranes due to alterations in glycerophospholipid metabolism, and weaken glycolysis/gluconeogenesis in the hypocotyl + cotyledon, both of which are major contributors to ABA-mediated inhibition of seed germination. These results highlight that the spatial modulation of metabolic pathways in Pinus koraiensis seeds underlies the germination response to ABA.

Osmopriming with selenium: physical and physiological quality of tomato seeds in response to water deficit

Abstract: Tomato is a crop sensitive to water deficit and the responses of seeds to germination under these conditions involve biochemical, physiological, and molecular processes. The aim of this study was to evaluate the physical, physiological, and biochemical changes in tomato seeds osmoprimed with selenium (Se) and subjected to water deficit during germination. Tomato seeds of the LA 4050 and LA 3475 accessions were osmoprimed with PEG 6000 solution (-1.0 MPa) plus Na2SeO4 (12.5 μM) or only with PEG 6000 solution for 24 h or unprimed. The seeds from the different treatments were subjected to water deficit (-0.3 MPa) or to control (0 MPa). Image analyses were performed (X-ray), physiological variables were obtained by the germination test and activities of SOD, CAT and POX enzymes were determined. Osmopriming, especially with PEG, provided the seeds of both accessions with higher densities and gray mean when compared to unprimed ones. Seeds under water deficit showed lower physiological performance and lower enzymatic activity. Se did not induce seed resistance to water deficit. Osmopriming with PEG 6000 at -1.0 MPa is an efficient technique for improving the physiological quality of seeds of tomato accessions susceptible and tolerant to water deficit. Moreover, the antioxidant enzyme CAT proved to be an indicator of oxidative stress tolerance in tomato seedlings under water deficit.

Fiber-dominated Soft Actuators Inspired by Plant Cell Walls and Skeletal Muscles

Morphing botanical tissues and animal muscles are all fiber-mediated composites, in which fibers play a passive and active role, respectively. Herein, inspired by the mechanism of fibers functioning in morphing botanical tissues and animal muscles, we propose two sorts of fiber-dominated composite actuators. First, inspired by the deformation of awned seeds in response to humidity change, we fabricate passive fiber-dominated actuators using non-active aligned carbon fibers via 4D printing method. The effects of process parameters, structural parameters, and fiber angles on the deformation of the printed actuators are examined. The experimental results show that the orientation degree is enhanced, resulting in a better swelling effect as the printing speed increases. Then, motivated by the actuation mechanism of skeletal muscle, we prepare active fiber-dominated actuators using active polyurethane fibers via 4D printing and pre-stretching method. The effect of fiber angle and loading on the actuation mode is experimentally analyzed. The experimental results show that the rotation angle of the actuator gradually decreases with the angle from 45° to 60°. When the fiber angle is 0° and 90°, the driver basically stops rotating while shrinking along the loading direction. Based on the above actuation mechanisms, identical contraction behaviors are realized both in passive and active fiber-dominated soft actuators. This work provides a validation method for biologically actuation mechanisms via 4D printing technique and smart materials and adds further insights to the design of bioinspired soft actuators.

Ecophysiological and Biochemical Responses Depicting Seed Tolerance to Osmotic Stresses in Annual and Perennial Species of Halopeplis in a Frame of Global Warming.

Plant abundance and distribution are regulated by subtle changes in ecological factors, which are becoming more frequent under global climate change. Species with a higher tolerance to such changes, especially during early lifecycle stages, are highly likely to endure climate change. This study compared the germination adaptability of Halopeplis amplexicaulis and H. perfoliata, which differ in life-form and grow in different environments. Optimal conditions, tolerances and the biochemical responses of seeds to osmotic stresses were examined. Seeds of H. perfoliata germinated in a wider range of temperature regimes and were more tolerant to osmotic stresses than H. amplexicaulis seeds. Neither NaCl nor PEG treatment invoked the H2O2 content in germinating seeds of the tested species. Consequently, unaltered, or even decreased activities of H2O2 detoxification enzymes and non-enzymatic antioxidants were observed in germinating seeds in response to the aforementioned stresses. High and comparable levels of recovery from isotonic treatments, alongside a lack of substantial oxidative damage indicated that the osmotic stress, rather than the ionic toxicity, may be responsible for the germination inhibition. Hence, rainy periods, linked to water availability, may act as a key determinant for germination and H. perfoliata could be less affected by global warming owing to better germinability under high temperatures compared with H. amplexicaulis. Such studies involving biochemical analysis coupled with the germination ecology of congeneric species, which differ in life-form and occurrence are scarce, therefore are important in understanding the impacts of global changes on species abundance/distribution.

Kinetics of Macro and Micronutrients during Germination of Habanero Pepper Seeds in Response to Imbibition

The aim of this study was to evaluate the concentration and distribution of a number of macro- and micronutrients in response to imbibition in habanero pepper seeds extracted from fruits with different stages of maturity and postharvest storage times, as well as in their seedlings. Fruits were harvested unripe, half-ripe, and ripe, and were subjected to storage for 0 (control), 7, and 14 days postharvest prior to seed extraction. An X-ray microfluorescence analysis was carried out on seeds pre- and post-imbibition, as well as on seedlings at 10 and 14 days after sowing. K, Ca, Fe, P, Mg, and Mn were detected by elemental analysis. The results indicated that the elements had a higher concentration and distribution in seeds extracted from half-ripe fruits and ripe unstored fruits, as well as in seeds extracted from fruits stored for 7 and 14 days postharvest. K and Ca were the elements with the highest distributions and concentrations in seeds and seedlings pre- and post-imbibition compared to the other elements. At all maturity stages, postharvest storage increased the concentration and distribution of mineral nutrients in seeds and seedlings before and after imbibition. Storage translocated mineral elements to the radicle before germination, increased meristem growth in emerged seedlings, decreased electrical conductivity, and increased germination. Fourteen days of postharvest storage increased the distribution of macro- and micronutrients in immature seeds, decreasing electrical conductivity, potentiating germination, and improving mineral element distribution in seedlings.

Germinability and Seedling Growth Performance of Chilli (Capsicum annuum) Seeds in Response to Different Gibberellic Acid Concentrations Pre-Treatment

Chilli seeds are always associated with physiological dormancy characteristics or endogenous dormancy that has affected their germination potential. Problems noticed on the low seed germination rate, vigour growth, further may lead to the poor seedling growth pattern of chilli crop production. Gibberellic Acid (GA3) which is usually used as a treatment solution is not a new advent of seed dormancy breaking methods for chilli. But, looking forwards to a better GA3 concentration is still needed for the discovery of this treatment potential effect on chilli seed germinability and seedling growth. Thus, this study aimed to evaluate the effect of different GA3 concentrations on seed emergence and seedling growth performance in chilli. In this experiment, chilli seeds were imbibed with 25 mg/L, 75 mg/L and 125 mg/L concentration of GA3 with three replications each; for 24 hours at room temperature (32±4°C) and the untreated seeds as a control. The data collection on final germination percentage was taken daily for 21 days after sowing. While the 15 germinated seeds were directly planted on the 5 polybags arranged in the net house of Junaidy Jonik Farm, Sabah, Malaysia. The experiment was arranged in a completely randomized design with three replications. Data were subjected to analysis of variance with SAS version 9.4 and the significant means were separated by the least significant difference test at P<0.05. Significant differences were observed in the seed germinability measured; germination rate index (GRI), mean germination time (MGT) and final germination percentage (FGP), as well as on seedling vigour index (SVI) between treated and control seeds. Conversely, plant height, number of internodes, number of leaves and fresh weight of seedlings showed no significant differences among treatments. It was concluded that the use of GA3 was able to enhance chilli seeds germinability and could display a better SVI than the control. It is recommended to use GA3 treatment at 25 mg/L of concentration, as it may give an advantage to both economic and biological importance in producing higher germinability and seedling growth performance in chilli.

Germinability and Seedling Growth Performance of Chilli (Capsicum annuum) Seeds in Response to Different Gibberellic Acid Concentrations Pre-Treatment

Chilli seeds are always associated with physiological dormancy characteristics or endogenous dormancy that has affected their germination potential. Problems noticed on the low seed germination rate, vigour growth, further may lead to the poor seedling growth pattern of chilli crop production. Gibberellic Acid (GA3) which is usually used as a treatment solution is not a new advent of seed dormancy breaking methods for chilli. But, looking forwards to a better GA3 concentration is still needed for the discovery of this treatment potential effect on chilli seed germinability and seedling growth. Thus, this study aimed to evaluate the effect of different GA3 concentrations on seed emergence and seedling growth performance in chilli. In this experiment, chilli seeds were imbibed with 25 mg/L, 75 mg/L and 125 mg/L concentration of GA3 with three replications each; for 24 hours at room temperature (32±4°C) and the untreated seeds as a control. The data collection on final germination percentage was taken daily for 21 days after sowing. While the 15 germinated seeds were directly planted on the 5 polybags arranged in the net house of Junaidy Jonik Farm, Sabah, Malaysia. The experiment was arranged in a completely randomized design with three replications. Data were subjected to analysis of variance with SAS version 9.4 and the significant means were separated by the least significant difference test at P<0.05. Significant differences were observed in the seed germinability measured; germination rate index (GRI), mean germination time (MGT) and final germination percentage (FGP), as well as on seedling vigour index (SVI) between treated and control seeds. Conversely, plant height, number of internodes, number of leaves and fresh weight of seedlings showed no significant differences among treatments. It was concluded that the use of GA3 was able to enhance chilli seeds germinability and could display a better SVI than the control. It is recommended to use GA3 treatment at 25 mg/L of concentration, as it may give an advantage to both economic and biological importance in producing higher germinability and seedling growth performance in chilli.

Lignin and organic free radicals in maize (Zea mays L.) seeds in response to aflatoxin B1 contamination: an optical and EPR spectroscopic study.

Aflatoxin B1 (AFB1 ) is the most dangerous of the mycotoxins that contaminate cereal seeds naturally. A stress lignin formation is linked with the accumulation of reactive oxygen species causing a change in the redox status and formation of stable organic radicals, constituting the first layer of defense. The relationship between AFB1 and changes in lignin organic free radicals in seeds is not known, nor is the part of the seed that is more targeted. Using optical and electron paramagnetic resonance spectroscopy, we investigated AFB1 -induced changes in lignin and organic free radicals in seeds, and whether the inner and outer seed fractions differ in response to increasing AFB1 . Different changes in the content of lignin and free radicals with increasing AFB1 concentrations were observed in the two seed fractions. There was a significant positive linear correlation (R=0.9923, P=0.00005) between lignin content and AFB1 concentration in the outer fraction, and no correlation between the lignin content and the AFB1 concentration in the inner fraction. We found a positive correlation between the area of the green spectral emission component (C4) and the AFB1 concentration in the outer fraction. To the best of our knowledge, the results showed, for the first time, that maize seed fractions respond differently to aflatoxin with regard to their lignin and organic free radical content. Lignin content and (C4) area may be reliable indicators for the screening of lignin changes against AFB1 content in the seeds, and thus for seed protection capacity. © 2021 Society of Chemical Industry.

Penularan Penyakit Layu Bakteri dan Hasil Kacang Tanah Lokal dengan Penambahan Dosis Bertingkat Pupuk K

Bacterial wilt R. solanacearum is one of the main diseases of peanuts that can reduce crop production. The use of local varieties and plant management can control bacterial wilt disease. Local varieties are one source of germplasm diversity for plant breeding activities. Management such as fertilization is expected to control pests and plant diseases. The aim of the study was to determine the performance of bacterial wilt disease and its effect on the yield of three local peanut varieties in West Nusa Tenggara with the addition of various doses of K fertilizer. The study was conducted at the Narmada Visitor Plot, on 17 January - 29 April 2017. The experiment used a split plot factorial design. The main plots were three varieties of local NTB peanuts, namely local peanuts North Lombok (KLU) (V1), local Bima (V2), and local Pelat (V3). Subplots are four levels of potassium (K) fertilizer dose, namely 0 kg KCl/ha (P1), 20 kg KCl/ha (P2), 40 kg KCl/ha (P3), and 60 kg KCl/ha (P4). Each treatment was repeated five block. The results showed that each local peanut varieties with doses of KCl fertilizer showed bacterial wilt resistance. The lowest transmission of bacterial wilt was in KLU local peanuts with a dose of 0 kg KCl/ha, 20 kg KCl/ha, and 40 kg KCl /ha, Bima at a dose of 40 kg KCl/ha and Pelat at a dose of 60 kg KCl/ha. The application of KCl fertilizer at a dose of 0 kg/ha to 60 kg/ha did not affect the yield and varieties of local peanuts had different weights of 100 seeds in response to the application of K fertilizer, local peanuts KLU and Pelat had the highest weights of 100 seeds at the KCl dose. 40 kg/ha while Bima at a dose of KCl 60 kg/ha.

Content and Accumulation of Macronutrients in Radish Seeds in Response to Sulfur and Organic Compost

Sulfur (S) is usually the second most accumulated nutrient in seeds of Cruciferae plant species such as the radish. Tropical soils have low S availability creating a challenge to manage plant nutrition and balanced plant development to produce high-quality seeds. This study evaluated the influence of S doses and organic compost fertilization on the content and accumulation of macronutrients in radish seeds. Eight treatments were studied in subdivided plots, where the presence (50 t ha-1) or absence of organic compost was placed in the main plot, and the S doses (0, 60, 120, 180 kg ha-1 of S) were placed in the subplots. A randomized block design with six replications was used. Seed dry weight, N, P, K, Ca, Mg, and S concentration (g kg-1 of dry matter), and the accumulation of nutrients in seeds (g plant-1) were evaluated. There was no significant effect of S doses, or organic compost, on the contents of macronutrients in radish seeds. When organic compost was not applied, great doses of S generated great dry weight and accumulation of macronutrients in the radish seeds. However, the application of organic compost increased the dry weight and the accumulation of all macronutrients in radish seeds in low S doses (up to 66 kg ha-1). Also, the presence of organic compost increased the dry weight and the concentration of macronutrients in radish seeds. The decreasing order of macronutrient content and accumulation by the radish seeds was: N > S > K > P > Ca > Mg.

Snow melt timing acts independently and in conjunction with temperature accumulation to drive subalpine plant phenology

Organisms use environmental cues to align their phenology-the timing of life events-with sets of abiotic and biotic conditions that favor the successful completion of their life cycle. Climate change has altered the environmental cues organisms use to track climate, leading to shifts in phenology with the potential to affect a variety of ecological processes. Understanding the drivers of phenological shifts is critical to predicting future responses, but disentangling the effects of temperature from precipitation on phenology is often challenging because they tend to covary. We addressed this knowledge gap in a high-elevation environment where phenological shifts are associated with both the timing of spring snow melt and temperature. We factorially crossed early snow melt and passive warming treatments to (1) disentangle the effects of snow melt timing and warming on the phenology of flowering and fruiting and reproductive success in three subalpine plant species (Delphinium nuttallianum, Valeriana edulis, and Potentilla pulcherrima); and (2) assess whether snow melt acts via temperature accumulation or some other aspect of the environment (e.g., soil moisture) to affect phenological events. Both the timing and duration of flowering and fruiting responded to the climate treatments, but the effect of snow melt timing and warming varied among species and phenological stages. The combined effects of the treatments on phenology were always additive, and the snow melt treatment often affected phenology even when the warming treatment did not. Despite marked responses of phenology to climate manipulations, the species showed little change in reproductive success, with only one species producing fewer seeds in response to warming (Delphinium, -56%). We also found that snow melt timing can act both through temperature accumulation and as a distinct cue for phenology, and these effects are not mutually exclusive. Our results show that one environmental cue, here snow melt timing, may act through multiple mechanisms to shift phenology.

Genome-Wide Association Studies of Seed Performance Traits in Response to Heat Stress in Medicago truncatula Uncover MIEL1 as a Regulator of Seed Germination Plasticity.

Legume seeds are an important source of proteins, minerals, and vitamins for human and animal diets and represent a keystone for food security. With climate change and global warming, the production of grain legumes faces new challenges concerning seed vigor traits that allow the fast and homogenous establishment of the crop in a wide range of environments. These seed performance traits are regulated during seed maturation and are under the strong influence of the maternal environment. In this study, we used 200 natural Medicago truncatula accessions, a model species of legumes grown in optimal conditions and under moderate heat stress (26°C) during seed development and maturation. This moderate stress applied at flowering onwards impacted seed weight and germination capacity. Genome-wide association studies (GWAS) were performed to identify putative loci or genes involved in regulating seed traits and their plasticity in response to heat stress. We identified numerous significant quantitative trait nucleotides and potential candidate genes involved in regulating these traits under heat stress by using post-GWAS analyses combined with transcriptomic data. Out of them, MtMIEL1, a RING-type zinc finger family gene, was shown to be highly associated with germination speed in heat-stressed seeds. In Medicago, we highlighted that MtMIEL1 was transcriptionally regulated in heat-stressed seed production and that its expression profile was associated with germination speed in different Medicago accessions. Finally, a loss-of-function analysis of the Arabidopsis MIEL1 ortholog revealed its role as a regulator of germination plasticity of seeds in response to heat stress.

Identification of MicroRNAs in Taxillus chinensis (DC.) Danser Seeds under Cold Stress.

Taxillus chinensis (DC.) Danser, a parasitic plant that belongs to the Loranthaceae family, has a long history of being used in the Chinese medicine. We observed that the loranthus seeds were sensitive to temperature and could lose viability below 0°C quickly. Thus, we performed small RNA sequencing to study the microRNA (miRNA) regulation in the loranthus seeds under cold stress. In total, we identified 600 miRNAs, for the first time, in the loranthus seeds under cold stress. Then, we detected 224, 229, and 223 miRNAs (TPM > 1) in A0 (control), A1 (cold treatment for 12 h at 0°C), and A2 (cold treatment for 36 h at 0°C), respectively. We next identified 103 differentially expressed miRNAs (DEmiRs) in the loranthus seeds in response to cold. Notably, miR408 was upregulated during the cold treatment, which can regulate genes encoding phytocyanin family proteins and phytophenol oxidases. Some DEmiRs were specific to A1 and may function in early response to cold, such as gma-miR393b-3p, miR946, ath-miR779.2-3p, miR398, and miR9662. It is interesting that ICE3, IAA13, and multiple transcription factors (e.g., WRKY and CRF4 and TCP4) regulated by the DEmiRs have been reported to respond cold in other plants. We further identified 4, 3, and 4 DEmiRs involved in the pathways “responding to cold,” “responding to abiotic stimulus,” and “seed development/germination,” respectively. qRT-PCR was used to confirm the expression changes of DEmiRs and their targets in the loranthus seeds during the cold treatment. This is the first time to study cold-responsive miRNAs in loranthus, and our findings provide a valuable resource for future studies.

Ultrastructure observation and transcriptome analysis of Chinese chestnut (Castanea mollissima Blume) seeds in response to water loss

Chestnut hardening is a physiological disorder that can occur after harvest. In this study, ultrastructure observation and transcriptome analysis were performed on samples collected at different time points during the chestnut hardening process. The SEM results showed that dehydration causes degradation of the cell wall and escape of starch granules from cells. Transcriptome analysis was performed, and a total of 40315 differential expressed genes were obtained and annotated into 50 GO terms and 20 major KEGG metabolic pathways. Weighted correlation network analysis of the DEGs revealed 12 co-expression modules, with 51–2965 DEGs in each module. Six co-expression modules significantly correlated with the chestnut hardening process. A total of 32 hub genes were screened by weight value and intramodular connectivity. The gene CMHBY209828 might play a key role in the chestnut hardening process. This research provides the theoretical basis to further understand the response of chestnuts to water loss.

Intraspecific pod and seed trait variation of two herbaceous legume seeds in response to competing neighbours and nutrient resource abundance

The presence of competing neighbours can exert pressure on parent plants, forcing them to adjust their reproductive strategies to maximize recruitment success (adaptive response); however, competitive neighbour effects may be suppressed if more nutrient resources are made available (passive response). In this study, we investigated if the response of some measured seed and pods traits of Lablab purpureus and Mucuna pruriens (focal plants) were adaptively determined by the presence of competitive neighbour species (using Megathyrsus maximus as the focal neighbour) or passively determined by nutrient resource availability. We measured four pod traits (pod weight, pod length, pod filling, and no of pods/ha) and eight seed traits (no of seeds/ha, seed mass, seed yield, dry matter content, Calcium content, Phosphorus content, Nitrogen content, and seed germination percentage) of the focal plants established as mixtures (neighbour treatment) or as monocultures (no-neighbour treatment) at different levels of phosphorus fertilizer application (0, 20, and 40 kg/ha applied on treatment basis). The data were analyzed using a linear mixed-effect model. Results showed that plant identity modified competitive neighbour and nutrient resource availability effects. Competitive neighbour species facilitated increased pod length response, but suppressed pod filling and number of pods/ha which were passively improved at higher levels of nutrient abundance. The no of seeds/ha and seed yield were also passively improved at higher levels of nutrient abundance, previously suppressed by competitive neighbour effects. The presence of focal neighbours and nutrient resource levels interacted positively to increase the Phosphorus content, Nitrogen content, and seed germination %. Other measured traits were not influenced by competitive neighbour effects or nutrient resource availability. In conclusion, competitive neighbour effects on the seeds and pod traits of the focal plants depended on plant identity and nutrient resource availability. Passive trait responses may magnify competitive effects on progenies after successful recruitment.