崇明东滩不同演替阶段湿地土壤有机碳汇聚能力的差异性及其微生物机制

旨在阐明崇明东滩不同演替阶段湿地土壤有机碳汇聚能力的差异性及其机制,以期为优化湿地的管理与保育措施,进而保持和提升湿地的碳汇功能提供理论指导和决策依据。研究结果表明,4个不同演替阶段湿地土壤有机碳含量和微生物呼吸强度有显著差异(P<0.05),中高潮滩处的土壤有机碳汇聚能力最高,这是由于其具有较高的有机碳输入(植物枯落物)和相对较低的碳输出(土壤呼吸)。PCR-DGGE分析和系统进化树结果表明,4个不同演替阶段土壤的微生物群落结构存在差异,一些特异性优势菌的存在可能是影响土壤微生物呼吸强度,并最终影响土壤有机碳汇聚能力的重要原因。出现在高潮滩的噬纤维菌和假单胞属菌具有较高降解纤维素等有机质的能力,它们的存在可能强化了高潮滩的土壤呼吸作用,从而降低了高潮滩土壤的有机碳汇聚能力。     

Thermal Resistance of Common Rice Maintainer and Restorer Lines to High Temperature During Flowering and Early Grain Filling Stages

Fifteen common rice maintainer lines and 26 high-yielding restorer lines were used to evaluate their thermal resistance and fertility during flowering and early grain filling stages.The rice plants were subjected to high temperature stress(39-43 ℃) for 1-15 d from main stem flowering.Based on the heat stress index,they were divided into thermal resistant lines,semi-thermal resistant lines,semi-thermal sensitive lines and thermal sensitive lines.Therefore,the maintainer lines K22B,Bobai B and V20B belonged to thermal resistant lines,whereas II-32B,Zhongzhe B and Zhong 9B belonged to thermal sensitive lines.For rice restorer lines,Minghui 63 had the highest thermal resistance,followed by R207,P32,P929,and the lowest thermal resistant lines P62-2-2,R8006 and P51.The correlation analysis indicated that the heat stress index was significantly correlated with seed-setting rate and abortive grain rate under heat stress,but not under natural conditions.This indicated that heat stress occurred during flowering and early grain filling stages mainly decreased the seedsetting rate and significantly increased the abortive grain rate in both rice maintainer and restorer lines.     

氨基酸对基因表达的影响

氨基酸除了作为蛋白质合成底物外 ,氨基酸在体内还发挥着其它重要的营养生理功能 ,例如作为糖异生的底物、作为神经递质和信号转导的前体及蛋白质周转的调节剂等。然而 ,大量研究证实氨基酸还作为营养信号分子调控着许多调节细胞功能和氨基酸代谢的基因的表达。氨基酸主要是通过影响DNA的转录和mRNA的稳定性和翻译而调控基因的表达。但是 ,氨基酸调控基因表达的分子机制仍然不十分清楚     

Production of cell-wall polysaccharide degrading enzymes in carrot root tissues infected by Mycocentrospora acerina.

Mycocentrospora acerina , the causal agent of liquorice rot of carrot roots, produces several cell-wall polysaccharide degrading enzymes in vitro . To assess the involvement of these enzymes in tissue invasion, the production and localization of pectin methylesterases, polygalacturonases, pectate lyases and endoglucanases were measured in root tissue infected by M. acerina . Isoelectrofocusing studies demonstrated the production of three isoforms of pectin methylesterase in healthy tissue. In infected tissue, two isoforms already observed in the culture filtrate and two novel isoforms were detected. Tissue maceration was associated with in vivo production of pectin methylesterase and polygalacturonase, which were first detected on the second day whereas pectate lyase and endoglucanase activities were detected only from the fourth day after infection. Maceration was always detected ahead of the mycelium, indicating diffusion of these enzymes.     

各国水产品生产及消费动向分析

简要介绍了世界主要国家水产品生产状况,分析了各国水产品消费量和消费趋势,并对各国水产品消费动向,特别是日本消费者生活方式、销售流通结构和质量价格观念方面进行了总结。     

水稻和稻瘟病菌互作中的信号传导及防御反应基因诱导表达的研究

 水稻和稻瘟病菌互作是研究植物与病原菌互作的模式体系。本文利用3个水稻抗稻瘟病近等基因品系(CO39、C101LAC和C101A51)和2个特异性菌株(M209和M210)构成不同亲和程度的互作关系,研究了稻瘟病菌对3个水稻信号传导途径关键酶合成基因、5个防御反应病程相关蛋白基因和1个防御反应转录因子调控基因诱导表达的作用。结果表明:稻瘟病菌诱导了各种互作关系中水稻OsLOX、OsAOS和OsPAL酶合成基因的表达,水稻启动了茉莉酸和水杨酸防御反应信号传导途径。在不亲和的互作反应中,稻瘟病菌能不同程度地诱导水稻OsPR1a、OsPR2、OsPR3-1、OsPR3-2和OsPR4基因的表达,从而有效激活了防御反应系统,使水稻植株表现为抗病;而在亲和的互作反应中,多数OsPR基因的表达水平低、时间短或没有表达,水稻植株表现为感病。OsMyb基因在各种互作关系中有不同的诱导表达。说明这些防御相关基因的诱导表达可能与水稻抗稻瘟病性相关。