Seedlings of zea mays l. (poaceae) and pterogyne nitens tul. (fabaceae): Morphoanatomic and terminological considerations / Plântulas de zea mays l. (poaceae) e pterogyne nitens tul. (fabaceae): Considerações morfoanatômicas e terminológicas

Seedlings of Zea mays L. (maize), Poaceae, and Pterogyne nitens Tul. (wild peanut), Leguminosae, are described morphologically and anatomically in order to characterize the species, but particularly to disseminate the terminology about the seedling, which is little known by non-specialist researchers and undergraduate students. Seedlings were obtained in the laboratory, using Petri dishes. Seedling was considered as the initial plant development phase, which comprises the period from germination to formation of the eophyll. Zea mays seedling is hypogeal and cryptocotyledonous, and it consists of coleorhiza, considered the primary root, endogenous embryonic root, commonly considered in the literature as radicle, reduced hypocotyl, and coleoptile, considered here as eophyll. The second seedling leaf of Z. mays is made up of uniseriate epidermis and homogeneous mesophyll. Pterogyne nitens exhibits epigeal and phanerocotyledonous seedling, and consists of primary root, long hypocotyl, two cotyledons, epicotyl, and opposite eophylls difoliolated or trifoliolated. The hypocotyl has root/shoot transition structure and the eophylls are dorsiventral consisting of one cell layer palisade parenchyma and pluriseriate spongy parenchyma. Seedlings of both species show significant morphological and anatomical differences and specific terminology, especially that of Z. mays.

Comparative transcriptome and metabolome analysis reveal glutathione metabolic network and functional genes underlying blue and red-light mediation in maize seedling leaf

Background Light quality severely affects biosynthesis and metabolism-associated process of glutathione. However, the role of specific light is still unclear on the glutathione metabolism. In this article, comparatively transcriptome and metabolome methods are used to fully understand the blue and red-light conditions working on the glutathione metabolism in maize seedling leaf. Results There are 20 differently expressed genes and 4 differently expressed metabolites in KEGG pathway of glutathione metabolism. Among them, 12 genes belong to the glutathione S-transferase family, 3 genes belong to the ascorbate peroxidase gene family and 2 genes belong to the ribonucleoside-diphosphate reductase gene family. Three genes, G6PD, SPDS1, and GPX1 belong to the gene family of glucose 6-phosphate dehydrogenase, spermidine synthase, and glutathione peroxidase, respectively. Four differently expressed metabolites are identified. Three of them, Glutathione disulfide, Glutathione, and l-γ-Glutamyl-L-amino acid are decreased while L-Glutamate is increased. In addition, Through PPI analysis, two annotated genes gst16 and DAAT, and 3 unidentified genes 100381533, pco105094 and umc2770, identified as RPP13-like3, BCAT-like1and GMPS, were obtained. By the analysis of protein sequence and PPI network, we predict that pco105094 and umc2770 were involved in the GSSG-GSH and AsA-GSH cycle in the network of glutathione metabolism. Conclusions Compared to red light, blue light remarkably changed the transcription signal transduction and metabolism of glutathione metabolism. Differently expressed genes and metabolic mapped to the glutathione metabolism signaling pathways. In total, we obtained three unidentified genes, and two of them were predicted in current glutathione metabolism network. This result will contribute to the research of glutathione metabolism of maize.

Plant height heterosis is quantitatively associated with expression levels of plastid ribosomal proteins

The use of hybrids is widespread in agriculture, yet the molecular basis for hybrid vigor (heterosis) remains obscure. To identify molecular components that may contribute to trait heterosis, we analyzed paired proteomic and transcriptomic data from seedling leaf and mature leaf blade tissues of maize hybrids and their inbred parents. Nuclear- and plastid-encoded subunits of complexes required for protein synthesis in the chloroplast and for the light reactions of photosynthesis were expressed above midparent and high-parent levels, respectively. Consistent with previous reports in Arabidopsis, ethylene biosynthetic enzymes were expressed below midparent levels in the hybrids, suggesting a conserved mechanism for heterosis between monocots and dicots. The ethylene biosynthesis mutant, acs2/acs6, largely phenocopied the hybrid proteome, indicating that a reduction in ethylene biosynthesis may mediate the differences between inbreds and their hybrids. To rank the relevance of expression differences to trait heterosis, we compared seedling leaf protein levels to the adult plant height of 15 hybrids. Hybrid/midparent expression ratios were most positively correlated with hybrid/midparent plant height ratios for the chloroplast ribosomal proteins. Our results show that increased expression of chloroplast ribosomal proteins in hybrid seedling leaves is mediated by reduced expression of ethylene biosynthetic enzymes and that the degree of their overexpression in seedlings can quantitatively predict adult trait heterosis.

Seed discontinuous hydration does not benefit germination, but improves drought tolerance of Triplaris gardneriana seedlings

The discontinuous seed hydration enables the acquisition of tolerance to environmental stresses, causing a stress imprint. It may modify metabolic patterns and lead to improved stress responses. This study aims to evaluate the effects of discontinuous hydration on germination and on seedling growth of Triplaris gardneriana Wedd. under intermittent drought. The seeds have gone through cycles (0, 1, 2 and 3) of hydration and dehydration (HD). The seedlings produced were subjected to water deficit (daily watering and intervals of seven and fourteen days between watering). Seed germinability parameters and, relative growth rate (RGR) of seedling, leaf area, dry matter yield and leaf relative water content (RWC) were evaluated. The HD cycles did not benefit germination, but two HD cycles induced a better biomass accumulation and increased leaf area in seedlings under moderate water deficit, while three HD cycles promoted an increase in RGR and influenced the RWC values. Severe stress affects seedling growth, but subjection to HD cycles minimizes the deleterious effects of drought, suggesting discontinuous hydration acts leading stress imprint in plants.

Germination and Seedling Leaf Chlorophyll Content of Wheat (Triticum aestivum L.) Grown under Industrial Wastewater Condition

The tobacco industry is one of the biggest industries in the world generates and disposes large quantities of wastewater in the environment which may be toxic to the plant, animal, public health as well as environment. Therefore, an experiment was conducted during November, 2019 at Crop Physiology and Ecology Laboratory, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh to observe the effects of tobacco industry wastewater on germination, early seedling growth and seedling leaf chlorophyll content of wheat (TriticumaestivumL.). Three wheat genotypes (BARI Gom 28, BARI Gom 29 and BAW 1177) and two growing conditions (normal tap water and tobacco industry wastewater) were assigned in a completely randomized design with three replications in germination test. Results showed that germination characteristics, seedling growth and chlorophyll content in leaf of seedling significantly influenced by wheat genotype, growing condition and their interaction. Irrigation with tobacco industry wastewater lowered the germination percentage, rate of germination, co-efficient of germination and vigor index. However, seedlings irrigated with tobacco industry wastewater produced longer shoot and root as compared to seedlings irrigated with tap water. Similarly, tobacco industry wastewater increased the shoot and root dry weight but reduced the chlorophyll content in leaf of seedling. Among the three wheat genotypes, BAW 1177 performed better under both tap water and wastewater conditions regarding germination, early growth and chlorophyll content in leaf of seedling. The Agriculturists 2020; 18(1) 10-17

Transcriptomic Analysis Revealed the Common and Divergent Responses of Maize Seedling Leaves to Cold and Heat Stresses

Temperature stresses (TS), including cold and heat stress, adversely affect the growth, development, and yield of maize (Zea mays L.). To clarify the molecular mechanisms of the tolerance of maize seedling leaves to TS, we applied transcriptomic sequencing of an inbred maize line, B73, with seedlings exposed to various temperature conditions, including normal temperature (NT, 25 °C), cold (4, 10, and 16 °C), and heat (37, 42, and 48 °C) stresses. Differentially expressed genes (DEGs) were detected in different comparison between the NT sample and each temperature-stressed sample, with 5358, 5485, 5312, 1095, 2006, and 4760 DEGs responding to TS of 4, 10, 16, 37, 42, and 48 °C, respectively. For cold and heat stresses, 189 DEGs enriched in the hydrogen peroxidase metabolic process, cellular modified amino acid metabolic process, and sulfur compound metabolic process were common. The DEGs encoding calcium signaling and reactive oxygen species scavenging enzymes demonstrated similar expression characterizations, whereas the DEGs encoding transcription factors, such as ERF, ARF, and HSF, hormone signaling, and heat shock proteins, displayed divergent expression models, implying both common and divergent responses to cold and heat stresses in maize seedling leaves. Co-expression network analysis showed that functional DEGs associated with the core regulators in response to cold and heat stresses were significantly correlated with TS, indicating their vital roles in cold and heat adaptation, respectively. Our investigation focused on the response to gradient TS, and the results presented a relatively comprehensive category of genes involved in differential TS responses. These will contribute a better understanding of the molecular mechanisms of maize seedling leaf responses to TS and provide valuable genetic resources for breeding TS tolerant varieties of maize.

Interaction of Biochar Type and Rhizobia Inoculation Increases the Growth and Biological Nitrogen Fixation of Robinia pseudoacacia Seedlings

Adding biochar to soil can change soil properties and subsequently affect plant growth, but this effect can vary because of different feedstocks and methods (e.g., pyrolysis or gasification) used to create the biochar. Growth and biological nitrogen fixation (BNF) of leguminous plants can be improved with rhizobia inoculation that fosters nodule development. Thus, this factorial greenhouse study examined the effects of two types of biochar (i.e., pyrolysis and gasification) added at a rate of 5% (v:v) to a peat-based growth substrate and rhizobia inoculation (yes or no) on Robinia pseudoacacia (black locust) seedlings supplied with 15NH415NO3. Seedling and nodule growth, nitrogen (N) content, and δ15N × 1000 were evaluated after 3 months. While addition of biochar without inoculation had no effect on seedling growth, inoculation with rhizobia increased seedling growth, BNF, and N status. Inoculated seedlings had reduced δ15N, indicating that N provided via fertilization was being diluted by N additions through BNF. Biochar type and inoculation interacted to affect seedling growth. Combining inoculation with either biochar type increased seedling leaf, stem, and total biomass, whereas gasifier biochar and inoculation improved all seedling growth variables and nodule biomass.