Potato Responds to Salt Stress by Increased Activity of Antioxidant Enzymes

To understand the response of potato to salt stress, antioxidant enzyme activities and ion content were analyzed for a sensitive and a tolerant cultivar. Nodal cuttings of the tolerant cultivar, Kennebec, and the sensitive cultivar, Concord, were exposed to media without or with 30, 60, 90 or 120 mmol/L NaCI for 4 weeks. On exposure to NaCI, the length and fresh and dry weight of both shoots and roots of Concord showed greater decrease than those of Kennebec. The decrease in shoot growth was more severe than that of the root for both cultivars. The K^＋ content of shoots and roots of both cultivars was reduced in a dose-dependent manner by exposure to NaCl; the Na^＋ content increased. Activities of ascorbate peroxidase, catalase and glutathione reductase were increased in NaCl-exposed shoots of Kennebec; the corresponding activities in NaCI-exposed shoots of Concord were decreased. Roots of both cultivars showed similar changes in the activities of these enzymes on exposure to NaCI. These studies established that enzyme activities in Concord shoots are inversely related to the NaCI concentration, whereas those in Kennebec do not show a dose dependency, which is also the case for the roots of both cultivars. Our findings suggest that an increase in activity of antioxidant enzymes, such as ascorbate peroxidase, catalase and glutathione reductase, can contribute to salt tolerance in Kennebec, a salt resistant cultivar of potato.     

高渗震动对杜氏盐藻细胞跨膜K^＋运输的影响

杜氏盐藻细胞吸收Ｋ＾＋的Ｋｍ为２．８６ｍｍｏｌ／Ｌ,Ｖｍａｘ为１．３９μｍｏｌ／１０＾８ｃｅｌｌｓ．ｈ。钒酸钠和ＤＥＳ、ＣＣＣＰ、Ｌｉ＾＋抑制藻细胞对Ｋ＾＋的吸收。高渗震动促进藻细胞Ｈ＾＋的分泌,降低Ｋ＾＋的吸收速率,ＣＣＣＰ和Ｌｉ＾＋减弱了高渗震动对藻细胞Ｋ＾＋吸收的抑制。高渗震动对藻细胞Ｋ＾＋分泌有轻微的抑制作用。     

酵母细胞渗透压调节与甘油代谢

酵母甘油代谢与调控的信息主要来自于酿酒酵母和酿酒酵母细胞对高渗应答的研究。本文综述了酵母细胞非协迫条件下的甘油合成与分解代谢特征;甘油在酵母细胞渗透压调节过程中的作用与酵母耐高渗机理;增强甘油合成的外环境及其甘油合成的途径工程;以及酵母感受胞外高渗信息及控制在高渗协迫条件下甘油合成的高渗甘油应答途径。     

NaCl胁迫下离体小鼠叶片内抗坏血酸与几种生理生化指标变化的…

随着ＮａＣｌ胁迫时间的延长和胁迫强度的增加，离体小麦叶片内抗坏血酸含量逐渐减少。活性氧清除剂处理可缓解由ＮａＣｌ胁迫所引起的抗坏血酸含量下降。ＮａＣｌ胁迫下，叶片内Ｏ＾－２和ＭＤＡ含量增加，叶绿素和类胡萝卜素含量，叶绿体的Ｈｉｌｌ反应活力，叶生光合速率，叶片和线粒体呼吸速率的下降，而外源抗坏血酸对这些过程均有缓解作用。     

脑室内注射心钠素和高渗盐水对大鼠隔区单位放电的影响

心钠素(ANP)广泛地分布在脑内,并以下丘腩和隔区内免疫阳性神经元和纤维最为密集。有人报道隔区是对致渴效应最敏感的区域之一,也是血管紧张素Ⅱ(AngⅡ)作用并诱发致渴最敏感的区域。近来,有人利用放射自显影方法观察到隔区内也存在加压素神经元。以上均说明此区域参与水、电解质平衡的中枢调节。目前,关于ANP对脑内神