施氮深度和水分胁迫对藜麦幼苗生理及产量的影响

为了探讨藜麦应对施肥深度和水分胁迫的响应,该文以藜麦(Chenopodium quinoa)为材料,在盆栽条件下,设置3种施氮处理[D1(控释尿素施在0～8 cm深度)、D2(控释尿素施在8～16 cm深度)、D3(控释尿素施在16～24 cm深度)]和3种水分处理[W1(正常供水)、W2(中度干旱)、W3(重度干旱)],分析施氮深度和水分胁迫对藜麦幼苗生理及产量的影响。结果表明：(1)相同水分条件下,随着施肥深度的增加,藜麦生长指标(株高、茎粗、叶面积、地上部生物量、主根长、根系表面积、根系体积)、生理指标[超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、可溶性糖含量、可溶性蛋白含量、叶绿素总量]和产量指标呈先升高后降低趋势。D2处理(适当的深施氮肥)均高于D1处理(浅层施氮)和D3处理(底层施氮)。(2)相同施氮深度条件下,随着干旱胁迫程度的增加,藜麦生长指标和产量指标呈逐渐降低的趋势,生理指标均呈先升高后降低的趋势。说明藜麦幼苗对水分需求明显,可通过增加抗氧化酶活性和渗透调节物质适应一定程度的干旱,生产实践中应注意苗期水分的供应,以促进生育后期产...     

串番茄果实货架期间与耐贮性有关的生理特性的变化

串番茄品种随着货架期延长,果实硬度、果肉硬度、原果胶含量逐渐下降;可溶性果胶含量逐渐上升;多聚半乳糖醛酸酶(PG)活性呈峰值变化,变化幅度小于普通番茄.     

核桃青皮分解对小白菜生长及生理特性的影响

采用盆栽试验,研究了不同剂量核桃(Juglans regia L.)青皮在土壤中分解过程中对受体植物小白菜(Brassica rapa L.var.chinensis)幼苗生长及其生理特性的影响,探讨核桃青皮的化感作用机理。结果表明:(1)核桃青皮在施入土壤的75d内,显著抑制了小白菜地上部分生物量的积累。(2)各剂量青皮处理小白菜叶片的叶绿素含量在施入20d时均较CK降低,且随着处理时间延长总体呈减少趋势。(3)各剂量青皮处理小白菜叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)活性在施入20d和75d时大多比对照显著升高,且有随剂量增加而增强的趋势,但过氧化氢酶(CAT)活性则随添加量增大或处理时间延长多无显著变化。(4)小白菜叶片可溶性糖(SS)含量在施入20d时随青皮添加量的增加而增加,后期则表现为显著下降,而可溶性蛋白(SP)和脯氨酸(Pro)含量在整个处理期则呈减少趋势。研究认为,核桃青皮在土壤中分解可能对小白菜的生长和抗性生理指标产生了明显的化感作用,其化感作用强度随其分解时间延长呈先强后弱的变化趋势,且高添加量产生的效应比低添加量快而且强。     

Ecological physiology of Pereskia guamacho, a cactus with leaves

The specialized physiology of leafless, stem-succulent cacti is relatively well understood. This is not true, however, for Pereskia (Cactaceae), the 17 species of leafy trees and shrubs that represent the earliest diverging lineages of the cacti. Here we report on the water relations and photosynthesis of Pereskia guamacho, a small tree of the semiarid scrubland of Venezuela's Caribbean coast. Sapwood-specific xylem conductivity (Ksp) is low when compared to other vessel-bearing trees of tropical dry systems, but leaf-specific xylem conductivity is relatively high due to the high Huber value afforded by P. guamacho's short shoot architecture. P. guamacho xylem is not particularly vulnerable to drought-induced cavitation, especially considering the high leaf water potentials maintained year round. This is confirmed by the lack of significant variation exhibited in Ksp between wet and dry seasons. In the rainy season, P. guamacho exhibited C3-like patterns of stomatal conductance, but during a prolonged drought we documented nocturnal stomatal opening with a concomitant accumulation of titratable acid in leaves. This suggests that P. guamacho can perform drought-induced crassulacean acid metabolism (CAM photosynthesis), although delta 13C values imply that most carbon is assimilated via the C3 pathway. P. guamacho leaves display very low stomatal densities, and maximum stomatal conductance is low whether stomata open during the day or night. We conclude that leaf performance is not limited by stem hydraulic capacity in this species, and that water use is conservative and tightly regulated at the leaf level.     

昆虫抗茵肽的生理活性及其转基因应用前景

昆虫抗菌肽是昆虫免疫后存在于血淋巴中的一类活性肽.根据分子的结构可分为5类天蚕素类、昆虫防御素、富含脯氨酸或精氨酸的抗菌肽、富含甘氨酸的抗菌肽、抗真菌肽.且具有广谱的抗菌、抗病毒、抑制肿瘤的生物活性.概述了昆虫抗菌肽的基因的克隆与表达及转基因研究方面的进展,并展望了抗菌肽在基因工程中的应用前景.     

不同降湿处理后温室内番茄作物生物学性状与生理特性差异研究

研究了限量排气降湿、地下热循环冷凝除湿、膜下滴灌降湿3个降(除)湿处理后温室内番茄作物生物学性状与生理特性差异。结果表明:3个降湿处理温室内番茄群体生长率、相对生长率与净同化率均明显高于对照;番茄植株茎粗、干物重、叶面积表现出膜滴>冷凝>限排>对照规律;相接近时刻的光合速率与蒸腾速率,以壮叶>嫩叶>老叶,且日变化呈现低(上午)、高(中午)、低(傍晚)规律,并明显大于对照。     

Antioxidant status of the potato tuber and Ca2+ deficiency as a physiological stress

The antioxidant status of potato ( Solanum tuberosum L.) tubers of two genotypes, cv. Désirée and clone 10337de40 was investigated in relation to susceptibility to internal rust spot (IRS), a Ca²⁺-related physiological disorder. Concentrations of total calcium within the perimedulla tissue of tubers, grown with a restricted (1 m M CaCl₂) Ca²⁺ supply, were similar in cv. Désirée (IRS resistant) and clone 10337de40 (IRS susceptible). A range of antioxidants was assayed in order to assess antioxidant status in both genotypes under the two Ca²⁺ treatments. Although no appreciable differences were detected between low Ca²⁺ and control treatments, certain antioxidants were present at significantly higher levels in the IRS resistant genotype, cv. Désirée. These included dehydroascorbate reductase (EC 1.8.5.1) activity (more than 100% higher), total glutathione content (ca 40% higher), glutathione reductase (EC 1.6.4.2) activity (almost 50% higher), peroxidase (EC 1.11.1.7) activity (ca 60% higher) and superoxide dismutase (EC 1.15.1.1) activity (almost 80% higher). There was no difference in ascorbate content, ascorbate free radical reductase activity (EC 1.6.5.4), α-tocopherol levels and catalase activity (EC 1.11.1.6) between the two genotypes. The possible relationship between resistance to IRS and a superior antioxidant status, found in cv. Désirée, is discussed.     

蓟马诱导的鹅掌柴叶片虫瘿组织的生理生化响应

以蓟马诱导的鹅掌柴叶片管状虫瘿为材料,分析了虫瘿和非虫瘿组织的抗氧化活性及其它生理响应以及营养物质的含量、分配等。结果发现虫瘿组织中许多生理指标如过氧化氢浓度、过氧化物酶和苯丙氨酸解氨酶活性以及丙二醛含量都比非虫瘿组织低。虫瘿组织比非虫瘿组织光合速率下降而呼吸速率增强,虫瘿组织转变为一个营养库能够富集较多的营养物质。仅仅使用植物激素和蓟马萃取物不能诱导虫瘿的形成,但是,细胞分裂素类植物生长调节物可以引起类似蓟马诱导虫瘿的早期反应。     

芝麻素研究进展

芝麻素是存在于芝麻种子和芝麻油中的木脂素类化合物中的一种,已从多种植物中分离出来。芝麻素具有较强的抗氧化活性,在生物体内具有降低血清胆固醇、调节脂质代谢、稳定血压和抗癌等多种生理学活性。本文综述了芝麻素的天然来源、分离检测方法及其生理学活性等方面的研究现状。     

新疆塔里木河下游生态输水与胡杨叶片的生理及形态响应

选择塔里木河下游3个典型断面的15个研究样地,分析和测定了塔里木河下游2000～2002年生态输水前后不同研究样地的地下水位、地下水含盐量和胡杨(Populus euphratica Oliv.)叶片中脯氨酸、可溶性糖、植物内源激素脱落酸和细胞分裂素的含量以及胡杨叶片的形态结构变化,研究了塔里木河下游主要建群种胡杨对生态输水的生理与形态的响应和适应性.结果表明,塔里木河下游胡杨生长已受到不同程度的干旱胁迫;输水后各样地地下水位均有所上升,胡杨对浅层地下水位的变化表现出明显响应,胡杨受到的生理胁迫降低,胡杨叶片角质层厚度、维管束导管官腔直径及管壁厚度皆随地下水位的上升而减少;随着地下水位的上升,地下水含盐量分别提高1.76～2.47倍,输水效果由于盐对植物的生理胁迫作用的增加而有所减弱;在塔里木河下游极端干旱环境下,胡杨林保育恢复的合适地下水位埋深为3.15～4.12 m,地下水含盐量为67.15～72.65 mm.