渗透胁迫和水淹对不同抗旱性小麦品种幼苗叶片多胺含量的影响

在根际渗透胁迫和离体叶片水淹条件下处理抗旱性小麦品种（旱选4号）和不抗旱性小麦品种（陇春10号）幼苗,结果表明：叶片中Put累积远大于Spd和Cad的含量．渗透胁迫下,旱选4号Put累积量大于陇春10号;而水淹时,两者Put相差不大,表明两种不同胁迫对不同小麦品种Put的生物合成和降解具有不问的作用．不同程度渗透胁迫的处理结果表明,在轻度胁迫下,多胺含量有较为明显的增加．提示多胺在胁迫防御反应中可能起第二信使或生长调节物质的作用．     

Overexpression of OsRAA1 promotes flowering and hypocotyls elongation in Arabidopsis

Previously, OsRAA1, an AtFPF1 homologue gene, was found to play an important role in modulating rice root development. In the current study, OsRAA1 was overexpressed in Arabidopsis, and the transgenic plants showed early flowering and elongated hypocotyl phenotypes as compared with the wild-type under white-light conditions. The hypocotyls of transgenic lines were twice as long as those of wild-type plants under red-light conditions but were indistinguishable from those of the wild-type under blue and far-red light and darkness. In addition, the phenotypes of AtFPF1 transgenic lines were similar to those of OsRAA1 transgenic lines. These results suggested that OsRAAI/AtFPF1 protein is involved in regulating flowering time and plays an important role in the inhibition of hypocotyl elongation under continuous red light. The functions were preserved during the evolution.     

渗透胁迫对冰草保护酶系统活性的影响

研究了不同浓度PEG胁迫下冰草SOD、POD、CAT活性变化。结果表明：随胁迫强度的增大,保护酶活性的变化幅度增大;随着胁迫时间延长,SOD活性先下降后升高．POD活性升高,CAT活性先升高后降低,保护酶活性总体上维持较高水平。研究表明,冰草对渗透胁迫有较强的适应能力,具有较强的抗旱性。     

Molecular characterization of GmNHX2, a Na＋/H＋ antiporter gene homolog from soybean,and its heterolosous expression to improve salt tolerance in Arabidopsis

Na＋/H＋ antiporters have been well documented to enhance plant salt tolerance by regulating cellular ion homeostasis. Here, a putative Na＋/H＋ antiporter gene homolog GmNHX2 from soybean was cloned and predicted to encode a protein of 534 amino acids with 10 putative transmembrane domains. GmNHX2 was expressed in all soybean plant tissues but enriched in roots and its expression was induced by NaCI and polyethylene glycol （PEG） treatments. GmNHX2 exhibits greater sequence similarity with LeNHX2 and AtNHX6 than that of AtNHX1 and AtSOS1. Although phylogenetic analysis clustered GmNHX2 with organellar （tonoplast and vesicles） antiporters, the GmNHX2-EGFP （enhanced green fluorescent protein） fusion protein was possibly localized in the plasma membrane or organelle membrane of transgenic plant cells, Furthermore, transgenic Arabidopsis plants expressing GmNHX2 were more tolerant to high NaCl concentrations during germination and seedling stages when compared with wild-type plants. These results suggest that GmNHX2 is a membrane Na＋/H＋ antiporter and may function to regulate ion homeostasis under salt stress.     

蛋白激酶与植物渗透胁迫耐受研究进展

蛋白激酶是一类能使其他蛋白质磷酸化的酶.在植物中,蛋白激酶几乎参与植物生命周期中一切生理调节过程.渗透胁迫是植物生长发育过程中常见的非生物胁迫,植物对渗透胁迫耐受的机理一直是研究的重点.本文着眼于植物渗透胁迫反应,详细介绍了分裂原激活蛋白激酶(MAPK)、钙依赖而钙调素不依赖的蛋白激酶(CDPK)、受体蛋白激酶(RPK)、核糖体蛋白激酶、转录调控蛋白激酶等多种蛋白激酶在植物逆境信号识别与转导中的作用,综述其研究进展及前景.分析了当前在植物抗渗透胁迫蛋白激酶研究中存在的问题,进而对解决问题的途径进行了探讨.     

Changes in the power spectrum of electrical signals in maize leaf induced by osmotic stress

To quantify the characteristics of the power spectrum of plant electrical signals, we defined the following concepts:spectral edge frequency (SEF), spectral center frequency (SCF), power index (PI) and power spectral entropy (PSE). These parameters were used to examine and quantify changes in the power spectrum of electrical signals in maize leaves under osmotic stress. In the absence of osmotic stress, the SEF of the electrical signal in maize leaves was approx. 0.2 Hz and the SCF was approx. 0.1 Hz. The electrical signal in maize leaves was mainly a slow wave signal with a frequency of 0-0.1 Hz. After 2 h osmotic stress, the SEF and SCF of the electrical signal increased to higher frequencies. The proportion of the fast wave frequency also increased to 0.1-0.2 Hz, resulting in a dramatic increase in PSE. We also found that the changes in PSE and SCF were significantly correlated during osmotic stress. We propose that the changes in the PSE and SCF in maize leaves can be used as a sensitive signal indicating water deficit in leaf cells under osmotic stress. Thus, measurement of SCF or PSE of electrical signals in maize leaves could be used to develop early warning and rapid diagnosis techniques for the water demands of plants.     

渗透胁迫对甘薯叶绿体超微结构及其膜脂过氧化的影响

用不同浓度的ＰＥＧ对甘薯进行根际渗透胁迫处理，研究了对叶绿体超微结构和膜脂过氧化的影响．结果表明，经不同浓度的ＰＥＧ渗透胁迫２４ｈ后，叶片细胞质膜透性、ＭＤＡ含量增加，ＣＡＴ活性升高；ＳＯＤ活性表现出品种抗旱适应特性．相同的渗透胁迫条件对抗旱性较强的渝薯２０的超微结构破坏明显小于抗旱性较弱的农大红．试验结果综合阐明了由渗透胁迫引发的活性氧累积对甘薯叶绿体膜结构具有强烈的损伤作用     

植物在渗透胁迫下信号转导的级联机制

研究植物在渗透胁迫下信号转导的级联机制,对于有效调控植物在逆境中的生长发育,提高其抗逆性和生存能力具有重要的指导意义．根据近年来国内外的研究成果和报道,综述了植物细胞在渗透胁迫下感受到信号后,相继产生许多信号分子,这些信号分子通过细胞壁-质膜-细胞骨架连续体,引起细胞骨架蛋白变构而传递信息,并与细胞膜蛋白、第二信使系统以及调节因子构成了信号传递网,最终有条不紊地引起特定的基因表达和应答．     

外源H2O2处理对小麦渗透性调节物的影响

以小麦品种西旱2号和宁春4号为材料,研究了不同浓度H₂O₂处理对其幼苗叶绿素、渗透性调节物质量分数及脯氨酸代谢相关酶活性的影响.与对照相比,50,100,200μmol/LH₂O₂处理下西旱2号幼苗叶片叶绿素a质量分数显著降低,而叶绿素b和叶绿素总量无显著变化;对宁春4号来说,不同浓度的H₂O₂处理使幼苗叶片叶绿素a,叶绿素b和叶绿素总量均显著降低.此外,外源H₂O₂处理诱导西旱2号幼苗叶片可溶性糖质量浓度和脯氨酸质量分数均显著增加,却使宁春4号可溶性糖质量浓度降低,且仅在200μmol/L H₂O₂处理下脯氨酸质量分数明显增加,但H₂O₂处理对两种小麦可溶性蛋白质质量浓度无影响.50,100μmol/L H₂O₂处理下西旱2号幼苗鸟氨酸转氨酶活性降为对照的78%,83%,200μmol/LH₂O₂处理使脯氨酸脱氢酶活性增加为对照的116%;而H₂O₂处理诱导宁春4号幼苗脯氨酸脱氢酶,鸟氨酸转氨酶活性均显著提高.结果表明:与宁春4号相比,西旱2号小麦幼苗叶片的光合色素在H₂O₂胁迫下受到较轻的破坏,却积累了较多的可溶性糖和脯氨酸,从而对H₂O₂胁迫表现出较强的耐受能力;H₂O₂处理诱导西旱2号幼苗叶片的脯氨酸积累与轻微变化的脯氨酸脱氢酶活性有关,而在宁春4号脯氨酸积累与H₂O₂诱导的鸟氨酸转氨酶活性升高有关.     

渗透胁迫对苗期不同品种春小麦叶片叶绿素荧光动力学的影响

利用OS1—FL调制式叶绿素荧光分析仪对渗透胁迫下的幼苗期春小麦叶片叶绿素荧光动力学参数的变化进行了研究。结果表明,渗透胁迫下4个品种春小麦叶片的可变荧光(F_v)、小麦叶片光系统Ⅱ(PSⅡ),原初光能转换效率(F_v/F_m)和PSⅡ潜在活性(F_v/F_o)均降低,光量子产额(Yield)减少,光合机构受到不同程度的损伤(F_m/F_o),以上各值经方差分析可知,在品种间、处理浓度、处理天数及以上各因素二二互作或三因素间互作等方面的结果皆达到显著或极显著水平。     

渗透胁迫下塔藓的4种生理指标的变化

以塔藓为材料，用PEG6000进行模拟干旱处理，研究3种不同程度PEG胁迫下的4种生理指标的变化。塔藓在受到轻度胁迫（10％PEG）时游离脯氨酸含量与对照相比稍变化，中度胁迫（20％PEG）和重度胁迫（30％PEG）时先降后升又降；塔藓分别受到轻度胁迫（10％PEG）、中度胁迫（20％PEG）和重度胁迫（30％PEG）时可溶性蛋白含量先降后升．但总是低于对照；塔藓在轻度胁迫（10％PEG）和重度胁迫（30％PEG）时SOD活性3d的变化是先升后降．但达到最高点的时间不同；中度胁迫（20％PEG）SOD活性是先升后降又升，重度胁迫（30％PEG）时SOD活性3d的变化是先升后降。POD活性在3种胁迫下总体的趋势是上升。塔藓的这4种生理指标不同与其它大部分植物的变化，可能是由于苔藓植物有一种特有的诱导恢复器官的原因。     

水分胁迫下杂交稻幼苗体内脯氨酸积累对膜指过氧化的影响

水分胁迫下杂交稻幼苗体内游离脯氨酸明显积累,腊脂过氧化产物丙二醛（MDA）含量显增加,脯氨酸积累速度同MDA的增生速度相关联。以外源脯氨酸对杂交稻幼苗进行预处理后胁迫,结果表明,外源脯氨酸能提高脯氨酸在稻苗体内的积累速度,能明显降低水份胁迫下杂交稻幼苗体内MDA含量增生水平,对膜脂过氧化有抑制效应。     

内蒙古中东部草原不同地理种群克氏针茅种子萌发对渗透胁迫的响应

利用聚乙二醇-6000（PEG-6000）模拟水分胁迫,研究了内蒙古典型草原不同地理种群克氏针茅种子对渗透胁迫的响应,并以相对发芽率、萌发抗旱指数、活力指数为指标采用模糊隶属法对为种群克氏针茅种子的耐旱性进行了综合评价.结果表明：不同浓度PEG处理的克氏针茅种子均存在萌发高峰期;50 g/L低浓度PEG-6000的渗透胁迫使克氏针茅萌发的整齐性提高;来源于典型草原东部相对湿润生境的巴彦乌拉克氏针茅种子比典型草原中部和西部相对干旱生境的锡林浩特西与新浩特克氏针茅种子对渗透胁迫更敏感;3个种群克氏针茅种子的耐旱能力依次为新浩特种子〉锡林浩特西种子〉巴彦乌拉种子;不同种群克氏针茅种子萌发的耐旱能力与生境有密切关系.     

几种渗压剂处理对大麦叶片某些生理性状的影响

就甘露醇、山梨醇、蜜二糖及其 PEG处理对大麦叶肉组织的生理生化影响进行了多方面的研究 ,发现 3 0 % PEG有利于幼苗的生长 ,不同浓度的 PEG影响渗压剂的生理作用 ,甘露醇处理有利于降低离子和生物大分子的渗漏 ,提高矿质元素的含量 ,减少可溶性蛋白的种类 ;山梨醇和蜜二糖则有与甘露醇不同的生理影响 ;还就 PEG和不同渗压剂的生理作用差异进行了机理上的探讨     

Identification of AtSM34, a novel tonoplast intrinsic protein-interacting polypeptide expressed in response to osmotic stress in germinating seedlings

Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved in this process, we used a yeast two-hybrid system to screen for potential binding partners to the Arabidopsis tonoplast intrinsic protein (TIP) AtTIP1;1. This was the first protein identified to be associated with high water permeability in vacuolar membranes from Arabidopsis thaliana. Using ...