森林对地气系统碳素循环的影响

本文研究了森林对地气系统碳素循环影响的机制和作用,并做了定量估算.结果表明,森林是除海洋外对地气系统碳素循环影响最大的自然因素;与海洋不同,森林可由人们管理和调控;人们通过保护和发展森林资源,扩大森林面积,提高森林生产率,控制采伐和防止毁林,可在一定程度上遏制大气中CO_2浓度增长和温室效应增强,从而对减缓和控制地球变暖将会起到积极作用.     

硅对盐胁迫下黄瓜幼苗根系质膜、液泡膜酶活性的影响

研究硅对盐胁迫下黄瓜幼苗生长及根细胞质膜H^＋-ATPase、液泡膜H^＋-ATPase、H^＋-PPase和Ca^2＋-ATPase活性的影响。结果表明：盐胁迫严重抑制黄瓜幼苗生长,根细胞质膜H^＋-ATPase、液泡膜H^＋-ATPase、H^＋-PPase和Ca^2＋-ATPase活性明显降低。硅处理明显提高盐胁迫黄瓜根液泡膜H^＋-ATPase、H^＋-PPase、Ca^2＋-ATPase活性,一定程度上维持了液泡膜质子泵活性,有效地防御了细胞质酸化,这可能是硅提高黄瓜耐盐性的一个重要因素。     

维生素B1和B2的萤光光度同时测定法

探讨了用同步荧光法测定维生素Ｂ１和Ｂ２的操作步骤和条件。维生素Ｂ１和Ｂ２的测定范围分别为质量浓度０．００１￣４．０００ｍｇ／Ｌ，０．０００５￣５．０００ｍｇ／Ｌ。该方法维生素Ｂ１的回收率在１０２％￣１０６％之间，维生素Ｂ２在８５．５％￣１０３．１％之间。     

Ethylene signalling is essential for the resistance of Nicotiana attenuata against Alternaria alternata and phytoalexin scopoletin biosynthesis

The phytohormone ethylene plays an important role in plant defence responses to pathogen attack. When infected by the necrotrophic fungal pathogen Alternaria alternata (tobacco pathotype), which causes severe diseases in Nicotiana species, the wild tobacco plant Nicotiana attenuata accumulates a high amount of the jasmonate (JA)‐dependent phytoalexin scopoletin to defend itself against this fungal pathogen. However, it is still not known whether ethylene signalling is also involved in scopoletin biosynthesis and the resistance of N. attenuata. After infection, ethylene biosynthetic genes were highly elicited. Furthermore, plants strongly impaired in ethylene biosynthesis or perception had dramatically decreased scopoletin levels, and these plants became more susceptible to the fungus, while A. alternata‐elicited JA levels were increased, indicating that the decreased defence responses were not due to lower JA levels. Thus, it is concluded that after infection, ethylene signalling is activated together with JA signalling in N. attenuata plants and this subsequently regulates scopoletin biosynthesis and plant resistance.     

牛奶葡萄贮藏中SO_2伤害及调控措施研究

牛奶葡萄采后SO2双重释放装置辅以CT－1处理不但有效降低了药害发生率，而且提高了贮藏效果。在此基础上辅以采前喷布内含杀菌剂的壳多糖，牛奶葡萄可达到更佳贮藏效果，在1998年生长季发生全国性洪水灾害，田间带菌量剧增，各地葡萄贮藏效果极差情况下，参试的牛奶葡萄腐烂率只有1．6％，果梗鲜绿，褐变指数只有0．4％，药害率仅为1．0％，果肉亚硫酸盐残留仅为0．067 mg／kg。     

TiO2-ZnO光催化性能及其降解苯酚废水动力学研究

以紫外光为光源,低浓度苯酚溶液模拟工业废水为处理对象,研究了自制TiO2-ZnO复合材料的光催化活性,考察了苯酚溶液初始浓度、催化剂投放量等对光催化降解的影响,并初步探讨了其反应动力学。结果表明,TiO2-ZnO复合催化剂对苯酚光催化降解反应符合一级动力学方程,光催化效果随苯酚初始浓度增加而降低,催化剂最佳投放量为2 g/L,TiO2-ZnO复合催化剂光催化活性高于纯TiO2、ZnO的光催化活性,是一种降解效果优异的光催化材料。     

不同浓度Na_2CO_3胁迫柳穿鱼幼苗的生理指标变化

为科学评价哈尔滨太阳岛自然植被种源柳穿鱼在不同浓度Na2CO3处理下的适应能力,以柳穿鱼实生幼苗采用5种浓度Na2CO3(5mmol/L,10mmol/L,20mmol/L,40mmol/L,80mmol/L)处理4周,测定其相对电导率、脯氨酸、可溶性蛋白、相对含水量、丙二醛、超氧化物歧化酶(SOD)6项生理指标。结果表明:柳穿鱼的相对电导率、脯氨酸与处理时间、浓度呈正相关;相对含水量与处理时间、浓度呈负正相关;可溶性蛋白含量随胁迫浓度增大而增大;5~10mmol/L处理组SOD活性逐渐上升,20~80mmol/L处理组SOD活性先升高后降低;无丙二醛含量检出。柳穿鱼幼苗在5mmol/L Na2CO3胁迫下无影响,能够通过自身调节适应10~20mmol/L Na2CO3胁迫,在40~80mmol/L Na2CO3胁迫下则枝叶干枯。     

Effect of lipopolysaccharide on L-type voltage-gated calcium channel currents in primarily cultured rat caudate nucleus neurons and its modulation by 2-arachidonoylglycerol

AIM: To explore whether L-type voltage-gated calcium channel (L-VGCC) currents are involved in neurotoxicity of lipopolysaccharide (LPS) and the neuroprotective mechanism of 2-arachidonoylglycerol (2-AG) in caudate nucleus (CN) neurons. METHODS: On the 7th day, the primarily cultured CN neurons were treated with 2-AG, LPS, SR141716A (a CB1 receptor inverse agonist) and AM630 (a CB2 receptor inverse agonist) for 12 h. The L-VGCC currents in the CN neurons were recorded using the whole-cell patch-clamp technique. Hoechst staining was used to detect the effect of 2-AG on neurotoxicity of LPS. Caspase-3 assay kit was used to determine the activity of caspase-3 induced by LPS alone or with 2-AG. RESULTS: LPS enhanced the current density of L-VGCC, but did not influence the activation and deactivation of L-VGCC. 2-AG inhibited the enhancement of L-VGCC currents induced by LPS. The effect of 2-AG on the suppression of L-VGCC currents induced by LPS was not mediated through CB1 or CB2 receptor. 2-AG alone did not affect the L-VGCC currents, activation and deactivation in the CN neurons. 2-AG inhibited LPS-induced elevated activity of caspase-3 in the CN neurons. This effect was inhibited by SR141716A. 2-AG inhibited the cell apoptosis induced by LPS, and this effect was mediated via CB1 receptor. CONCLUSION: Endocannabinoid 2-AG may exert the anti-inflammatory and neuroprotective effects through the modulation of L-VGCC currents in primarily cultured rat CN neurons.     

施硒对暗棕壤硒状况和森林蔬菜硒积累的影响

以培育富硒森林蔬菜为目标,在暗棕壤上进行了荚果蕨、小叶芹、小根蒜、婆婆丁等4种山野菜施硒试验。硒肥种类为亚硒酸钠,施硒量为0.10~10.00mg kg-1,直接施肥范围为0~15cm表土。经过一个完整的生长周期(1a)后测定土壤和植物硒指标。结果表明,典型暗棕壤对外源亚硒酸钠态硒具有较强吸收与保持能力,从低剂量至高剂量施入的硒有90%~70%以上仍保留在原施硒土层内;其中H2O可溶态硒占全硒的6.03%~3.78%,KH2PO4浸提的有效态硒占全硒的19.36%~37.54%,而且土壤全硒、KH2PO4浸提的有效态硒及H2O可溶态硒皆与最初的施硒量呈线性正相关。在土施强化供硒条件下,4种山野菜均能高量富集硒,其含硒量为对照的1.7~158.9倍;不同植物的富硒能力有差异,它们在递增施硒情况下高量富集硒的变化模式也各有特点。总体来看,山野菜含硒量与施硒量之间为非线性正相关关系,但在一定的较低施硒量范围内这种关系则是线性的,线性范围因植物而异;土壤的可溶态硒、KH2PO4浸提的有效硒甚至全硒等指标与山野菜含硒量之间亦均呈明显的非线性正相关,且施硒量较低时其关系亦表现为线性。初步得出,典型暗棕壤控制施硒是在近自然条件下培育富硒森林蔬菜并获取高富硒生物资源的有效途径;不过,强烈搅动的砂砾质暗棕壤却不利于硒肥保持和植物吸收,不适于富硒森林蔬菜栽培。     

磺胺二甲嘧啶残留检测免疫传感器的感受器部件研制

试验研究了用于检测磺胺二甲基嘧啶(SM2)残留的免疫生物传感器的最关键组成,即感受器部件的制备方法、最佳检测条件,并对所制备感受器部件的性能进行了测试。利用二醋酸纤维素作为载体支架结构,戊二醛为交联剂,己二胺为制孔剂,制备了最佳条件符合标准的载体膜。采用双盲评分法测定其性能,选取性能良好的载体膜包被SM2抗体制成抗体膜。将酶标抗原和SM2标准品联到抗体膜上,应用溶解氧分析仪测定体系中过氧化氢减少量。结果表明,质控膜和测定膜的电流变化值差异显著(P<0.05),感受器部件反应灵敏,最低检测限达5μg·L-1。