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Environmental and experimental botany
Pergamon Press,
Environmental and experimental botany

Pergamon Press,

0098-8472

Environmental and experimental botany/Journal Environmental and experimental botanySCIISTP
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    Root cell wall remodeling mediates copper oxide nanoparticles phytotoxicity on lettuce (Lactuca sativa L.)

    Guo, XinyuLuo, JipengZhang, RanGao, Hairong...
    13页
    查看更多>>摘要：Root cell wall (RCW) remodeling induced by copper oxide nanoparticles (CuO NPs) and its consequences for root growth of lettuce (Lactuca sativa L.) were investigated in this study. The results showed that a low concentration of CuO NPs (5 mg L-1) stimulated reactive oxygen species (ROS) signaling, led to the degradation of pectin by H2O2, and promoted root elongation by 22.1% by triggering RCW loosening. However, under treatment with a high concentration of CuO NPs (450 mg L-1), the unordered distribution of pectin homogalacturonan enhanced cell wall adhesion. Also, the increased xyloglucan and the decreased xyloglucan endotransglycosylase/hydrolase (XTH) activities caused cell wall stiffening, making it difficult for lettuce roots to extend. Meanwhile, the contents of hemicellulose and low-methylated pectin were increased remarkably due to the downregulation of the encoding genes XTH15, XTH17, XTH31 and the upregulation of PME3, which provided abundant binding sites of RCW with CuO NPs. In addition, the accelerated development of the apoplastic barrier and root lignification blocked the absorption of CuO NPs, and the endodermal cell walls were doubled in thickness, greatly enhancing their retention capacity to CuO NPs. Taken together, the above findings suggest that CuO NPs have concentration-dependent effects on lettuce roots, which are associated with plant tolerance and mediated by RCW remodeling.
      原文链接:
    • NSTL
    • Elsevier

    Boron mediates nitrogen starvation-induced leaf senescence by regulating ROS production and C/N balance in Brassica napus

    Ding, GuangdaXu, FangsenWang, YouqiangZhao, Zhe...
    12页
    查看更多>>摘要：Rapeseed (Brassica napus) is highly sensitive to nitrogen (N) and boron (B) deficiencies. However, little is known about the effect of N and B interaction on rapeseed growth and the underlying mechanism of B regulating N starvation-induced leaf senescence in Brassica napus. In this study, B deficiency accelerated the senescence of old leaves induced by N starvation stress in B. napus, while young leaves were more susceptible to B deficiency under N-sufficient condition. B deficiency enhanced SGR1-mediated chlorophyll degradation, exhibiting the chlorosis phenotype of old leaves. The excessive production of reactive oxygen species (ROS) in old leaves was regulated by the photooxidation damage and the up-regulation of RBOHDs under B deficiency. The senescence-associated genes SAG12s were strongly enhanced by B deficiency in response to the ROS over-accumulation. However, B-sufficient supply improved the antioxidant capacity to alleviate ROS toxicity under N starvation. Metabolic analysis showed that B deficiency improved N remobilization from source to sink and increased sugar accumulation in the old leaves, resulting in a significant increase in the C/N ratio. In addition, B deficiency further disrupted the balance of C and N pools through GABA (gamma-aminobutyri acid) shunts, which negatively regulated the leaf senescence process. Our results provide a comprehensive model for balancing B and N application in rapeseed production to optimize plant growth.
      原文链接:
    • NSTL
    • Elsevier

    Wheat breeding for early heading: Does it improve grain yield under drought stress and well-watered conditions?

    Dorrani-Nejad, MaryamKazemipour, AliMaghsoudi-Moud, Ali AkbarAbdolshahi, Roohollah...
    10页
    查看更多>>摘要：Terminal drought stress strongly affects wheat grain yield under Mediterranean conditions. Therefore, developing early-heading bread wheat cultivars in these conditions is an important breeding strategy. In the present research, earliness was transferred from the Australian cultivar, Excalibur, to three Iranian cultivars, Roshan, Kalheydari and Mahdavi, in separate backcross (BC) breeding programs from 2012 to 2018. The earliest and latest heading genotypes of each BC3 population, were selected as near-isogenic lines (NILs). NILs and their parents were assessed under diverse field conditions including rain-fed, moderate drought stress and wellwatered conditions in three locations, Kerman, Sepidan and Semirom, during two growing seasons, 2018-2019 and 2019-2020. Breeding for early heading significantly improved earliness in all genetic backgrounds and increased grain yield by 36.4% and 9.6%, in the rain-fed and moderate drought stress conditions, respectively. Whereas, grain yield was not significantly affected by early heading under well-watered conditions. Results showed that breeding for early heading, a highly heritable trait, is an appropriate method to increase grain yield and reduce water consumption under drought stress and well-watered conditions, respectively. Based on these findings, we recommend transferring early heading to high yield late heading commercial cultivars using backcrossing.
      原文链接:
    • NSTL
    • Elsevier

    Melatonin delays leaf senescence and improves cucumber yield by modulating chlorophyll degradation and photoinhibition of PSII and PSI

    Liu, KunJing, TongtongWang, YananAi, Xizhen...
    15页
    查看更多>>摘要：Decreases in chlorophyll and photosynthetic efficiency co-occur during aging and leaf senescence. Here, we report the positive functions of melatonin (MT) in delaying leaf senescence in cucumber plants. The results showed that natural leaf senescence induced the accumulation of endogenous MT and that spraying MT delayed leaf senescence in a concentration-dependent manner. Moreover, application of MT and transient overexpression of CsASMT, the key gene in MT synthesis, both suppressed leaf senescence simulated by darkness. This was evidenced by a decrease in expression of the senescence-related gene SAG12 and the cell death-related gene PDCD, an increase in chlorophyll content in terms of downregulation of chlorophyll-degradation genes and normal chloroplast structure, and higher activity of PSI and PSII reaction centers, electron transfer efficiency and photosynthesis-associated protein levels, compared with these measures in the H2O-treated seedlings. In addition, the data from field spraying experiments demonstrated that MT indeed alleviated the decline in chlorophyll content and increased photosynthetic efficiency in both functional and senescent leaves, which ultimately promoted the growth and yield of cucumber in the solar greenhouse. Together, these results indicate that MT acts as a positive regulator to downregulate SAG12 and PDCD mRNA abundances and alleviate damage to the photosynthetic apparatus by suppressing chloroplast disintegration and photosynthesis-associated protein degradation during leaf senescence.
      原文链接:
    • NSTL
    • Elsevier

    A transcriptomic study reveals salt stress alleviation in cotton plants upon salt tolerant PGPR inoculation

    Akbar, AdnanHan, BeiKhan, Aamir HamidFeng, Cheng...
    10页
    查看更多>>摘要：Soil salinity is a major constraint for reducing crop productivity worldwide. To combat this situation, the current project was aimed to examine the effect of plant growth-promoting rhizobacteria (PGPR) inoculation on the growth of cotton (Gossypium hirsutum, var. Jin668) plants during salt stress and to identify salt stress-responsive genes in cotton plants. For this purpose, two bacteria, Bacillus subtilis and Bacillus pumilus were selected among the 20 strains isolated from the cotton rhizosphere under the salt stress (200 mM NaCl) and identified by 16 S rRNA sequencing. B. subtilis and B. pumilus were applied to Jin668 plants under salt stress which enhanced resistance to salt stress (leaf and root growth) compared to only salt-treated plants and control plants. Transcriptomic analysis revealed 556 differentially expressed genes (481 up-regulated and 75 down-regulated) in the B. subtilis + Salt versus Salt treatments and 943 (536 up-regulated and 407 down-regulated) genes in the B. pumilus + Salt versus Salt treatments. KEGG analysis of B. pumilus + Salt versus Salt and B. pumilus + Salt versus Salt revealed the pathways plant-pathogen interaction and plant hormone signal transduction were expressed in both treatments, while ascorbate and aldarate metabolism pathways and glyoxylate and dicarboxylate metabolism pathways were uniquely expressed in the B. pumilus + Salt versus Salt comparison, and the pentose and glucuronate interconversions pathway was uniquely expressed in the B. pumilus + Salt treatment versus Salt comparison. These data showed that B. subtilis and B. pumilus significantly enhance salt stress tolerance in cotton plants during salt stress conditions.
      原文链接:
    • NSTL
    • Elsevier

    Short-term N and P additions differentially alter the multiple functional traits and trait associations of a desert ephemeral plant in China

    Zhou, Xiao-BingLi, Yong-GangLiu, Hui-LiangZhang, Yuan-Ming...
    15页
    查看更多>>摘要：Nitrogen (N) and phosphorus (P) are the main restrictive elements in terrestrial ecosystems. In a N-deficient desert, low exogenous N input is conducive to plant growth; however. However, the influence of P and N additions on the growth and physiology of desert plants remains controversial. In this study, Alyssum linifolium, an ephemeral plant widely distributed in the Gurbantunggut Desert in China, was administered with different amounts of N (CK, N1, N2, and N3: 0, 3, 6, and 18 g N m(-2) yr(-1), respectively), P (CK, P1, P2, and P3: 0, 0.6, 1.2, and 3.6 g N m(-2) yr-(1), respectively), and N + P (CK, N1P1, N2P2, and N3P3) to systematically analyze the effect of these additions on soil nutrients and plant multiple traits. Certain N-P interaction effects were observed on soil properties (15 out of 18) and plant traits (13 out of 33). N addition markedly improved soil N availability and plant N content and reduced plant P content; meanwhile, soil P availability remained steady. P addition enhanced soil P availability and plant P concentration but severely decreased soil N availability. N + P addition improved the effectiveness of soil N and P, thereby promoting plant N content but largely reducing plant P content. N and N + P additions remarkably enhanced the photosynthetic capacity, soluble protein content, allocation proportion of leaf biomass, and even individual growth (including plant height, root length, leaf length, and organ biomass) and chlorophyll content at low concentrations. Leaf N was negatively scaled to P under each nutrient treatment, and this trend was completely different from that in natural ecosystems. The effect of N and P under N + P addition differed from those under individual N and P additions. In addition, plant trait networks differed with nutrient treatment, and the network complexity and trait association were weakened markedly under P addition. A degree of modularity was observed in the plant trait network in response to N and P additions, and biomass accumulation was identified as the hub trait. Multivariate analysis showed that available soil N and N:P levels were the primary factors influencing the variation in plant traits. Structural equation modeling revealed that soil N availability regulated the allocation of photosynthetic products by affecting plant stoichiometry, enzyme activity, and photosynthetic capacity. In conclusion, P addition alone markedly reduced soil N availability and plant performance in N-deficient habitats, and low-concentration N or N + P addition was generally conducive to soil nutrient availability and plant growth.
      原文链接:
    • NSTL
    • Elsevier

    Does long-term salt stress of environmentally relevant concentrations affect the physiology of inland lichens? - The importance of rainfall to restore thallus vitality

    Chowaniec, KarolinaLatkowska, EwaRola, Kaja
    11页
    查看更多>>摘要：During winter seasons, sodium chloride is the most widely used de-icing agent for road maintenance. The aim was to determine the effect of long-term spraying with salt solutions of environmentally relevant concentrations on the physiology of two epigeic lichens i.e., Peltigera didactyla and Cladonia rei. We also aimed at studying lichen responses to rainfall simulations between salt treatments to verify whether the liquid water supply would improve the physiological condition of both symbiotic partners. Long-term salt stress led to a gradual loss of cell membrane integrity, but the damage was lower in the case of an experiment in which thalli were treated with salt solutions and water. Salt stress significantly affected the peroxidation of membrane lipids in both studied species, but their responses differed. Thiobarbituric acid reactive substances (TBARS) level in P. didactyla increased very late in comparison to C. rei, in which the highest TBARS concentrations were observed at the beginning of the experiment, and then decreased over time. This may be associated with the activation of defence mechanisms protecting against reactive oxygen species. The cyanobiont in P. didactyla was more sensitive to salt stress than the green algal photobiont in C. rei. A low possibility of photosynthesis reactivation of P. didactyla at high humidity may explain the earlier decrease in FV/FM compared to C. rei; whereas the stronger reaction of this species may result from irreversible changes associated with ionic effects. Moreover, significantly higher FV/FM values were recorded in the salt-water experiment in both species. Therefore, we conclude that rainfall could cause at least a partial recovery of the water potential by photobionts and trigger the process of photosynthesis. This is of key importance for lichens, which are constantly exposed to salt stress in the winter season, and rainfall may enable them to continue their physiological processes and survival.
      原文链接:
    • NSTL
    • Elsevier

    TIP1;1 expression could modulate the recovery of stomatal opening during rehydration in Sorghum bicolor

    Schley, Thayssa RabeloFranco, Danilo MiralhaAraujo Junior, Joao PessoaMaia, Ivan de Godoy...
    11页
    查看更多>>摘要：Stomatal conductance (g(s)) takes longer to recover after drought when compared to leaf water potential or leaf water content (RWC). Aquaporins, known for transporting water through membranes, could modulate g(s) recovery. Using Sorghum bicolor, we tested whether members of the plasma membrane (PIP) and tonoplast (TIP) intrinsic aquaporin subfamilies could influence g(s) after a 20-day drought. Potted plants under soil field capacity (control), severe water deficit (SWD; 30% (m/m) soil water content), and progressive severe water deficit (PSWD; water withheld until maximum stress) were used. Soil (Psi(soil)), predawn (Psi(PD)), and midday (Psi(MD)) leaf water potentials, photochemical, and gas exchange parameters were measured during drought and 12 days of recovery. After 17 days of drought, g(s) of SWD and PSWD was 4-times lower than control, and it took 6 days to recover. Psi(PD), Psi(MD), and RWC, however, recovered after 24 h. SbPIP1;2, SbPIP2;5, and SbTIP1;1 were all downregulated on the day of maximum stress, but only SbTIP1;1 showed consistent alleviation of its downregulation as g(s) recovered. SbTIP1;1 expression was positively correlated with g(s), leaf transpiration, and hydraulic conductivity (K-L), but only in SWD plants. The slow g(s) recovery seems to be associated with the alleviation of SbTIP1;1 down-regulation as rehydration progresses.
      原文链接:
    • NSTL
    • Elsevier

    Knockout of a novel salt responsive gene SlABIG1 enhance salinity tolerance in tomato

    Li, YingYang, LumingQiang, XinJia, Zhiqi...
    10页
    查看更多>>摘要：Salt stress can seriously reduce crop yield and quality, causing huge economic losses. Identification and functional of salt stress regulator could provide us a way to improve plants tolerance to salt stress. The HD-ZIP II subfamily is plant-specific transcription factors, plays a crucial role in plant development and abiotic stress. In this study, we analyzed the expression profiling of all HD-ZIP II members response to salt, drought, high temperature and cold stress using publicly accessible transcriptome data, and identified a novel salt stress negative regulator SlABIG1 in tomato. Under salt stress, knockout of SlABIG1 significantly improved the salt tolerance of tomato, with higher chlorophyll content and photosynthetic capacity, root dry weight and proline; decreased the accumulation of ROS, MDA and Na+. Collectively, our results revealed that SlABIG1 plays a key role in tomato tolerance to salinity stress and provide a candidate novel gene to create salt-tolerant tomato varieties in future.
      原文链接:
    • NSTL
    • Elsevier

    Co-overexpression of AVP1, PP2A-C5, and AtCLCc in Arabidopsis thaliana greatly increases tolerance to salt and drought stresses

    Balasubramaniam, ThuvarakiWijewardene, InoshaHu, RongbinShen, Guoxin...
    15页
    查看更多>>摘要：Abiotic stresses such as salinity and drought impose a severe constraint on global food production, posing a serious challenge in agriculture. Stacking beneficial genes in transgenic crops will likely improve crop yield under abiotic stress conditions. Previous studies showed that individually overexpressing the Arabidopsis vacuolar H+-pyrophosphatase gene AVP1, the protein phosphatase 2 A catalytic subunit gene PP2A-C5, and the chloride channel protein gene AtCLCc contributed to enhanced salt tolerance and overexpression of AVP1 alone could also improve drought tolerance. We hypothesized that co-overexpressing AVP1, PP2A-C5, and AtCLCc, would combine the benefits of these three genes, leading to a further increase in salt tolerance in transgenic plants due to the potential synergism of these genes. Indeed, co-overexpression of these three genes in Arabi-dopsis significantly improved salt and drought tolerance under single as well as under combined salt and drought stresses. The AVP1/PP2A-C5/AtCLCc co-overexpressing plants displayed robust growth and produced greater amount of biomass as well as viable seeds than wild-type and single gene overexpression plants under saline and drought conditions. This study demonstrates that successful co-overexpression of several well-chosen genes is an effective strategy to achieve greater abiotic stress tolerance and could potentially lead to higher crop yield in regions of the world with saline soil and low precipitation.
      原文链接:
    • NSTL
    • Elsevier