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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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    Rhythmical redox homeostasis can be restored by exogenous melatonin in hulless barley (Hordeum vulgare L.var. nudum) under cold stress

    Chang, Tian-liangXi, Qian-qianWei, Xiang-yuXu, Li...
    11页
    查看更多>>摘要：Melatonin plays an important role in the ability of plants to adjust circadian rhythm and respond to abiotic stresses. Under stress conditions, exogenous melatonin can improve plant stress resistance by regulating the activity of plant antioxidant enzymes. However, little is known about the effects of exogenous melatonin on redox shock in plants. We measured the indexes related to redox maintenance of exogenous melatonin in pre-treated hulless barley seedlings at different temperatures. Under cold stress conditions, pretreatment with 1 mu M exogenous melatonin restored the rhythmic accumulation of hydrogen peroxide in hulless barley seedlings, as well as the rhythmic accumulation of superoxide dismutase (SOD) and catalase (CAT). In addition, pretreatment with 1 mu M exogenous melatonin conferred a certain protective effect on the transcription-independent rhythmic marker PRX-SO2/3. Additionally, key physiological indicators, such as MDA and soluble sugars, also exhibited rhythmic accumulation under the action of exogenous melatonin pretreatment. Collectively, these data show that pretreatment of exogenous melatonin can help plants sustain stable redox homeostasis under cold stress. According to the previous research, exogenous melatonin could recovery the rhythm of core circadian genes TOC1 and CCA1, it also indicated that the close interaction between circadian system and redox homeostasis.
      原文链接:
    • NSTL
    • Elsevier

    Elevated root-zone temperature promotes the growth and alleviates the photosynthetic acclimation of cucumber plants exposed to elevated [CO2]

    Li, DiDong, JinlongGruda, Nazim S.Li, Xun...
    16页
    查看更多>>摘要：Greenhouse cultivation forms a relatively closed environment for heat preservation in winter, which inevitably leads to a lack of atmospheric CO2 concentration ([CO2]), and thus low [CO2] level has become a limiting factor for the photosynthesis and growth of greenhouse vegetables. Most cucurbits and solanaceous vegetables are sensitive to low temperature, but it is difficult to keep the optimum root-zone temperature (RZT) for them in greenhouse soil cultivation in winter. Therefore, low RZT is another limiting factor for greenhouse vegetables growth in winter. This study investigated the effects of [CO2], RZT, and their interactions on cucumber yield, growth, photosynthesis, and photosynthate allocation in four open-top chambers for a growth period of 73 days after transplanting. We found elevated RZT increased yield and total dry weight of cucumber plants to a greater extent than elevated [CO2]. We also observed long-term elevated [CO2] limited the increase of net photosynthetic rate (Pn) and decreased the stomatal conductance (Gs) and transpiration rate (Tr) of cucumber plants at ambient RZT, resulted in the photosynthetic acclimation, as illustrated by the significant reduction of nitrogen concentration and the increased concentrations of soluble sugar and starch in leaves. In comparison, the combination of elevated [CO2] and RZT decreased the concentrations of soluble sugar and starch and maintained the nitrogen concentration in leaves, which caused a higher Pn, Gs and Tr. Meanwhile, more soluble sugar and starch were allocated from leaves to roots due to the higher root respiratory under elevated [CO2] and RZT treatment. Moreover, elevated RZT could facilitate the mineral nutrients absorption by roots and the upward transportation because of the larger root system and higher Tr. Therefore, elevated RZT could offset the decrease in Pn and improve Gs and Tr under elevated [CO2], which indicated an alleviation of the photosynthetic acclimation of cucumber plants exposed to long-term elevated [CO2].
      原文链接:
    • NSTL
    • Elsevier

    Possible mechanism of inoculating Oryza sativa L. with endophytic bacteria under ambient air and ozone stress

    Autarmat, SawitreeTreesubsuntorn, ChairatThiravetyan, Paitip
    9页
    查看更多>>摘要：The increasing ozone concentration in Asia impedes rice production. Applying plant growth-promoting bacteria (PGPB) is one of the biological tools to improve agricultural production. However, underlying mechanisms are still unclear. In this study, PGPB, including Bacillus thuringensis (BT), Lysinibacillus sp. N5 (N5) and Bacillus sp. N7 (N7), were added as inoculants to Oryza sativa L. ssp. indica cv. Pathumthani 1 (PTT1) and Oryza sativa L. ssp. indica cv. RD41 (RD41). Rice productivity without bacterial inoculation in PTT1 was higher than that of RD41 under ambient air. Moreover, inoculation with BT and N7 was more effective in improving appearances of rice (seed length and seed width) for both cultivars under ambient air. Elevated ozone levels can significantly decrease indole-3-acetic acid (IAA), photosynthesis rate and ascorbic acid content, resulting in decreased rice yields. Inoculating PGPB (BT, N5 and N7) significantly increased rice quality as 100-grain weight and seed width under ozone stress. Rice inoculated with N5 and N7 performed best under high ozone levels; these bacteria could alleviate ozone stress by increasing IAA production, photosynthesis capability and ascorbic acid content. In addition, rice inoculated with bacteria had lower malondialdehyde (MDA) than rice without inoculation under ozone stress. Therefore, the application of a suitable microorganism as a biofertiliser could be an alternative biological tool to mitigate rice yield losses under ozone stress.
      原文链接:
    • NSTL
    • Elsevier

    Conjugated polyamines are involved in conformation stability of plasma membrane from maturing maize grain embryos under drought stress

    Du, HongyangLiu, DongxiaoLiu, GutingLiu, Huaipan...
    14页
    查看更多>>摘要：Polyamines are closely associated with drought stress in plants. However, the function which polyamines play in the maturing maize grain under drought is not still clear. Especially, whether the conjugated polyamines are involved in H+-ATPase activity and conformation of plasma membrane remains to be answered. Therefore, in the study, the contents of conjugated polyamines, H+-ATPase activity and conformation of plasma membrane were detected with maturing grain embryos of two maize (Zea mays L.) cultivars, which were different in drought stress-tolerance. Under drought stress, the cell plasmolysis of the drought-sensitive Xundan No. 22 cv. was more marked than that of the drought-tolerant Yedan No. 13 cv., while the increases in the contents of conjugated noncovalently spermidine and spermine, conjugated covalently putrescine and spermidine in plasma membrane from Yedan 13 were more obvious than those in Xundan 22. The results suggested that these conjugated poly amines might be involved in stability of plasma membrane. Furthermore, H+-ATPase activity in plasma membrane from Yedan 13 increased more significantly than that in Xundan 22, indicating that these conjugated polyamines were closely correlated with the activity of H+-ATPase. To justify further the inferences, the additional experiments with exogenous spermidine, spermine and polyamine biosynthesis inhibitors were carried out in the study. The results showed that the application of exogenous spermidine or spermine increased the levels of conjugated polyamines in plasma membrane, coupled with alleviating cell plasmolysis and increasing H+-ATPase activity. The application of inhibitors decreased the levels of conjugated polyamines, coupled with aggravating cell plasmolysis and decreasing H+-ATPase activity. From these results together, it could be concluded that noncovalently conjugated spermidine and spermine, conjugated covalently putrescine and spermidine in plasma membrane functioned in increasing H+-ATPase activity, mitigating cell plasmolysis and maintaining the plasma membrane conformation of the maturing maize grain embryos under drought stress.
      原文链接:
    • NSTL
    • Elsevier

    Molecular analysis indicates the involvement of Jasmonic acid biosynthesis pathway in low-potassium (K+) stress response and development in chickpea (Cicer arietinum)

    Deepika, DeepikaAnkitJonwal, SarveshMali, Komal Vitthalrao...
    16页
    查看更多>>摘要：K+ is a major macronutrient and its deficiency hampers plant growth and yield. Plants combat low-K+ stress by modifying their root system architecture (RSA). Here, morphophysiological analysis revealed that chickpea plants exhibit sensitivity to low-K+ stress as shown by impaired primary root growth. Phytohormone JA regulates various facets of plant root growth, however, information of JA biosynthesis genes in chickpea is missing. We performed genome-wide identification and molecular characterization of JA biosynthesis pathway genes in chickpea. Total 33 genes belonging to different families i.e., LOXs-18, AOSs-3, AOCs-2, OPRs-6 and JARs-4 were identified in the chickpea genome. In-planta analysis revealed the localization of CaLOX7, -10, CaAOS1, -2 and CaAOC1 at subcellular compartments, such as membrane, chloroplast and cytoplasm. Protein expression and in -vitro enzymatic activity analysis showed that CaAOS1 an CaOPR2 are the functional enzymes in chickpea. Promoters of most genes harboured abiotic stress, hormone and development related cis-regulatory elements, suggesting their role in nutrient deficiency, abiotic stress and plant development. qRT-PCR expression profiling showed that about 15 JA biosynthesis genes from different families express differentially whereas, JA catabolism genes were repressed in chickpea root and shoot under low-K+ stress. In addition, JA biosynthesis genes showed differential expression in vegetative and reproductive development, senescence stages, desiccation, salinity and cold stress. These findings indicate the involvement of JA biosynthesis pathway in low-K+ stress response and development in chickpea. Low-K+ stress and development related genes identified in this study could be utilized in genetic engineering of chickpea plants for improved traits.
      原文链接:
    • NSTL
    • Elsevier

    Maternal drought stress on Persian oak (Quercus brantii Lindl.) affects susceptibility to single and combined drought and biotic stress in offspring

    Fayyaz, PayamSolla, AlejandroZolfaghari, RoghayehDalvand, Forough...
    11页
    查看更多>>摘要：Zagros woodlands in Iran are threatened by the decline of Persian oak (Quercus brantii) trees. Although the main cause of tree mortality is drought stress, bacterial pathogens such as Brenneria goodwinii also contribute to tree dieback. Maternal effects were studied in a drought-affected environment. We investigated if the susceptibility of Q. brantii seedlings to single and combined B. goodwinii and drought stresses depends on the health status of mother trees. Plants were grown from seeds collected from non-stressed healthy and drought-stressed unhealthy trees. Root weight and belowground to aboveground weight ratios were significantly higher in offspring of unhealthy mother trees, suggesting that drought stress regulated the performance of Q. brantii in the subsequent generation. Brenneria goodwinii followed by drought had synergistic negative effects on seedlings (reduced plant growth, reduced xylem vessel size and reduced relative water content of tissues) and induced more injury (reduced leaf chlorophyll content and increased root electrolyte leakage) in offspring of unhealthy trees. Increased adaptation to drought in plants germinating from drought-stressed trees was observed and the effects persisted over the vegetative period, after the plants were rewatered. The results provide a first evidence of transgenerational plasticity in response to drought stress in trees. It is concluded that the health status of trees influences the response of offspring to combined stress.
      原文链接:
    • NSTL
    • Elsevier

    Simultaneous elevation of acid-insoluble lignin and syringyl lignin is the preliminary Cd detoxification strategy in a Cd pollution-safe cultivar (Cd-PSC) of Brassica parachinensis L.

    Wang, Xue-songYang, Qiu-lingHe, Chun-taoPeng, Mi-jun...
    11页
    查看更多>>摘要：Cadmium (Cd) immobilization in the cell wall is responsible for Cd detoxification in Cd-accumulating cultivars. Lignin is the dominant constituent of the secondary cell wall (SCW), but its role in Cd compartmentalization is poorly understood. The mechanism of Cd compartmentalization by lignin was thus investigated herein. Lignin content and composition, as well as related genes and proteins, were analyzed in the Cd pollution-safe cultivar Brassica parachinensis L. 'SJ19'. The lignin microstructural regions and Cd affinities were characterized by 2Dheteronuclear single quantum coherence nuclear magnetic resonance (HSQC NMR) and density functional theory (DFT). Lignin combined with 14.2% of the total Cd in SJ19, with a higher Cd distribution in acid-insoluble lignin (AIL). Additionally, the proportion of AIL increased under Cd treatment. The increase in the proportion of the lignin aromatic region syringyl (S) and decrease in the guaiacyl (G) proportion were in accordance with the significant up-regulation of peroxidase P7 and down-regulation of caffeoyl-CoA O-methyltransferase At1g67980 under Cd stress. Moreover, the Cd affinity associating with the lignin aromatic region ranked as S > G> H (p- hydroxyphenyl). Therefore, rather than lignin biosynthesis, the simultaneous elevation of AIL and S lignin was recognized as the preliminary strategy for lignin compartmentalization of Cd in SCW for the first time herein. This is beneficial for Cd detoxification in the Cd pollution-safe cultivar of B. parachinensis.
      原文链接:
    • NSTL
    • Elsevier

    Susceptibility and tolerance of fenugreek (Trigonella foenum-graceum L.) to salt stress: Physiological and biochemical inspections

    Banakar, Mohammad HosseinAmiri, HamzehArdakani, Mohammad Reza SarafrazRanjbar, Gholam Hassan...
    10页
    查看更多>>摘要：Greenhouse experiments were conducted to evaluate the effects of soil salinity on some physiological and biochemical attributes of fenugreek (Trigonella foenum-graecum L.) and its tolerance for salt using some empirical models. The treatments included different salinity levels of irrigation water (0.5, 2, 4, 6, 8, 10 and 12 dS/m) which were arranged in the form of a randomized complete block design with three replicates. Some physiological and biochemical properties were measured at the vegetative stage and trigonelline at seed ripening. As the results showed, salinity reduced leaf area, relative water content, water use efficiency, and leaf water potential, but it increased leaf thickness, greenness index, canopy temperature, sodium, ash, electrolyte leakage, malondialdehyde (MDA) and the other aldehydes. Salt stress also reduced photosynthetic pigments, chlorophyll a/b ratio, leaf soluble protein, potassium, K+/Na+ ratio, photochemical efficiency of photosystem II (PSII) and canopy air temperature difference (CATD) index. Like catalase (CAT) and ascorbate peroxidase (APX) activities, the activity of superoxide dismutase (SOD) was increased up to 6 dS/m and then decreased. Furthermore, proline concentration was increased up to 8 dS/m and decreased at higher salinities. The increased salinity enhanced seed trigonelline up to 6 dS/m and then decreased it. According to a linear model, the salinity threshold tolerance and the yield reduction slope were 1.28 dS/m and 4.9%, respectively. Nonlinear models, however, showed a yield reduction of 10%, 25% and 50% at the soil salinity of 3.38, 6.28 and 11.67 dS/m, respectively. The salinity tolerance index was found to be 12.24. Therefore, fenugreeks can be considered moderately sensitive to salinity at the vegetative growth stage. It may also be grown on slightly to moderately saline lands. Some characteristics may be considered as selective criteria to identify the cultivars of fenugreek that tolerate salt stress.
      原文链接:
    • NSTL
    • Elsevier

    OsSIRH2-23, a rice salt-induced RING finger protein H2-23, contributes to insensitivity to salinity stress

    Kim, Ju HeeKim, Jong HoJung, Ki-HongJang, Cheol Seong...
    13页
    查看更多>>摘要：Degradation of proteins via the 26 S proteasome system is an important step in stress-responsive signaling networks in plants. Here, we characterized the rice RING-type E3 ligase gene, OsSIRH2-23, (previously named OsRFPH2-23) induced by salinity. OsSIRH2-23 encodes a cellular protein with a C3H2C3-RING finger domain in its C-terminal region and has E3 ligase activity. OsSIRH2-23 expression was substantially higher in the above-ground parts than in the subterranean part. The OsSIRH2-23-EYFP fusion protein was localized in the nucleus, cytoplasm, and plasma membrane under normal conditions, but mainly the cytoplasm and plasma membrane under saline conditions. Additionally, an interacting partner, OsSalT, jacalin-like lectin domain-containing protein, was identified using yeast two-hybrid and bimolecular fluorescence assays, and an in vitro ubiquiti-nation assay showed that OsSIRH2-23 ubiquitinated the OsSalT protein. To investigate the possible role of OsSIRH2-23 in salt stress responses, the phenotypes of wild type (WT), OsSIRH2-23-overexpressing and ossirh2-23 T-DNA insertion mutant rice plants were analyzed. OsSIRH2-23-overexpressing plants showed better insensitivity to salinity than WT and ossirh2-23. OsSIRH2-23-overexpressing plants had a lower Na+/K+ ratio and higher accumulation of proline than WT and ossirh2-23 plants. Furthermore, qRT-PCR data suggested that OsSIRH2-23-overexpressing plants showed salt insensitivity by reinforcing the expression of several rice trans-porters (OsHKT1;5, OsHKT2;1, OsSOS1, and OsNHX1) involved in Na+/K+ homeostasis and salt-induced genes (OsDREB2A and OsNAC1) under salt stress conditions. Thus, these results provide experimental evidence that OsSIRH2-23 is an important regulator of Na+ and K+ regulation and plays a critical role in salt insensitivity, possibly by modulating the expression of transporters and salt-responsive genes.
      原文链接:
    • NSTL
    • Elsevier

    Physiological and DNA methylation analysis provides epigenetic insights into chromium tolerance in kenaf

    Tang, MeiqiongYue, JiaoHuang, ZhenHu, Yali...
    11页
    查看更多>>摘要：As a toxic heavy metal, chromium (Cr) has become a major environmental concern in cultivated areas. Kenaf is a fast-growing fibre crop with high economic value and can potentially be used for phytoremediation. However, limited information is known regarding the mechanism of kenaf in response to Cr stress, especially from the perspective of epigenetics. The present study was conducted to explore the physiological and DNA methylation changes in kenaf seedlings grown under different concentrations (from 0 to 600 mu M) of Cr stress. The results show that Cr reduced plant height, root length, biomass, and root cell viability compared with the control. The activities of antioxidant enzymes (SOD, POD, and CAT) increased under Cr stress and reached their peaks at Cr concentrations of 500, 300, and 400 mu M respectively. Methylation-sensitive amplification polymorphism (MSAP) analysis revealed a significant positive correlation between an increase in the total DNA methylation level and Cr concentration, and the increasing rate ranged from 20.97% to 26.34%. Among the 205 loci examined, 40 differentially methylated DNA fragments (DMFs) were cloned and analysed. DMFs such as the ABC transport family (ABC) may play essential roles in kenaf Cr stress. In addition, the methylation status of three Cr stress related DMFs (HcABC, HcRHP and HcTyDC) was investigated via the bisulfite sequencing polymerase chain reaction (BSP) method. Furthermore, knockdown of HcTyDC by virus-induced gene silencing (VIGS) led to increased sensitivity to Cr stress. Overall, our data indicate that higher antioxidant activity and increased cytosine methylation levels in the plant genome could be related to Cr tolerance mechanisms in kenaf, and these changes then affect the expression of specific genes involved in the Cr stress response.
      原文链接:
    • NSTL
    • Elsevier