Calcium-induced movement of troponin-I relative to actin in skeletal muscle thin filaments

The role of troponin-I (the inhibitory subunit of troponin) in the regulation by Ca2+ of skeletal muscle contraction was investigated with resonance energy transfer and photo cross-linking techniques. The effect of Ca2+ on the proximity of troponin-I to actin in reconstituted rabbit skeletal thin filaments was determined. The distance between the cysteine residue at position 133 (Cys133) of troponin-I and Cys374 of actin increases by approximately 15 angstroms on binding of Ca2+ to troponin-C. Also, troponin-I labeled at Cys133 with benzophenone-4-maleimide could be photo cross-linked to actin in the absence of Ca2+, but not in its presence. These results suggest that troponin-I is attached to actin in the Ca2(+)-free or relaxed state of muscle, and that it detaches from actin on Ca2+ activation of contraction. Thus, troponin-I may function as a Ca2(+)-dependent molecular switch in regulation of skeletal muscle contraction.     

沼泽湿地与周边旱田气温、相对湿度差异分析

2010年6-9月份,采用大气温、湿度自动记录仪测定三江平原典型积水沼泽湿地及周边旱田近地面3个高度(0.5、2.0、5.0m)的气温和相对湿度,对比分析湿地和旱地上空气温和相对湿度的空间分布特征.结果表明:相对于周边旱田,沼泽湿地具有气温低和相对湿度大的特性,有显著的冷湿小气候效应.在垂直方向上,贴地层0.5m高度的...     

海南岛土壤发生分类类型在系统分类中的归属

本文对海南岛 2 3 7个土壤剖面 ,按中国土壤系统分类体系 ,逐一进行鉴别、检索、分类定名 ,阐述按土壤发生分类体系的 2 8个亚类级土壤类型在中国土壤系统分类中的归属 ,提出按中国土壤系统分类的该岛土壤分类系统建议 ;并讨论了该岛土壤发生分类与系统分类之间具体土壤类型的对应关系。     

滴灌条件下冬小麦田间土壤蒸发的测定和模拟

田间蒸发蒸腾总量(ETa)及其各分量的变化过程是农田水分利用与管理的主要依据。该文采用微型蒸发器(micro-lysimeters,MLS)对不同滴灌制度及覆盖处理下冬小麦田间土壤蒸发(Es)进行测定及评价。研究结果表明,滴灌条件下,采用内径10 cm,高度15 cm的MLS,在无降雨时每5 d换土能满足田间Es测定的精度要求(误差5%);滴灌条件下覆盖处理Es和Es/ETa均显著低于不覆盖处理,各处理的Es均值在0.98~1.30 mm/d之间,Es/ETa在33.0%~44.5%之间。此外,构建了基于灌水后天数(Dai)为自变量的Es简易估算模型,可在不获取表层土壤含水率的情况下,实现对滴灌条件下土壤蒸发较为精准的估算。该研究所建立的Es估算模型提供了滴灌农田Es的一种量化方法,确定的Es占ETa比例及其受覆盖等农艺措施的影响可为相关农业水管理实践提供科学指导。     

Activities of digestive enzymes and histology of digestive system during larval development of devil stinger (Inimicus japonicus)

Devil stinger is a valuable demersal scorpaenid fish while the rearing of stinger larvae still relies on live prey. This study was conducted to illustrate the development of the main digestive enzymes and digestive system during larval development of this species to provide evidence for the application of artificial feeds. Enzymatic and histological assays were conducted from 1 day post hatching (dph) to 36 dph in larvae. The result showed that the selected digestive enzyme activities increased significantly after 15 dph. Specifically, the total trypsin activities increased significantly from 18 dph to 33 dph. The total pepsin and amylase activities increased significantly first and thereafter decreased significantly. The lipase activities followed the similar pattern with trypsin. With regard to the histological study, the stinger larvae open their mouth to first feeding at 3 dph and turned into totally exogenous nutritional stage at 6 dph. In addition, mucous membrane, rich in goblet cells, was widely distributed in oesophagus epithelium at 18 dph. The height and amounts of gastric gland in cardia and main body of the stomach increased gradually with the development of stinger larvae after 15 dph. The intestine length of stinger larvae was short, and goblet cell was abundant in anterior intestine after 12 dph, not the posterior intestine. The ontogeny of liver and pancreas started from newly hatched stage, and the differentiation of liver was prior to pancreas. The above findings would provide evidence for the use of artificial feeds from the larval stage of stinger larvae (at least from 21 dph).     

不同小麦品种对土壤含盐量的响应及品种耐盐阈值

通过对10个小麦品种在大田条件下试验,用株高对土壤含盐量的响应评价小麦的耐盐能力,确定不同小麦品种的耐盐阈值.结果表明,德抗961、济南17和山融3号等3个品种生长期间表现出高耐盐碱能力.试验发现小麦品种产量与土壤含盐量存在极显著的负相关关系.盐碱地试验误差较大,会造成试验精确度降低.     

喷施表油菜素内酯对籼稻和粳稻花时的影响

以6个籼稻品种和6个粳稻品种为试验材料,于调查花时性状的前日17:00、当日6:00及8:00分别喷施低浓度（0.01mg/L）、中浓度（0.10mg/L）和高浓度（1.00mg/L）的2,4-表油菜素内酯（epi-BR）,以喷施不含epi-BR的水溶液为对照,调查6个与花时有关的性状在不同处理间的差异,包括始花时、盛花时、终花时、从始花时到盛花时的时间（简称始-盛时间）、从盛花时到终花时的时间（简称盛-终时间）、开花持续时间（简称始-终时间）。结果显示,不同浓度的epi-BR对供试品种的始花时、盛花时和终花时提前均有促进作用。籼稻品种中,0.10mg/L浓度的epi-BR促进花时提前的效果最明显,而粳稻品种中,1.00mg/L浓度的epi-BR促进花时提前的效果最明显。籼稻上施用高浓度（1.00mg/L）、中浓度（0.10mg/L）的epi-BR可显著缩短始-盛时间;粳稻上只有施用高浓度（1.00mg/L）的epi-BR才能缩短始-盛时间。与对照相比,施用epi-BR可显著延长盛-终时间和始-终时间。供试籼稻品种以调查花时性状的当日6:00喷施epi-BR促进花时提前的效果最为明显,供试粳稻品种以调查花时性状的前日17:00喷施促进花时提前的效果最好。供试籼稻品种比粳稻品种对epi-BR的响应更为敏感。促进籼稻花时提前的最佳处理是调查花时性状的当日6:00喷施中浓度（0.10mg/L）的epi-BR,促进粳稻花时提前的最佳处理是调查花时性状的前日17:00喷施高浓度（1.00mg/L）的epi-BR。     

Mapping of Verticillium Wilt Resistance QTL with Interspecific Advanced Backcross Population between Upland Cotton (Gossypium hirsutum L.) and Sea-Island Cotton (G. barbadense L.)

[Objective] The aim of this study was to map quantitative trait loci (QTLs) of Verticillium wilt resistance in cotton. [Method]In this study, with the cultivar Lumianyan 28(Gossypium hirsutumL.) as the recipient parent and the F₁generation obtained from the cross Hai7124 (G. barbadense) and TM-1(G. hirsutumL.) as the donor parent, an interspecific advanced backcross population was constructed. Compared with the integrated high density genetic linkage map published, simple sequence repeat(SSR) markers of polymorphism were used to construct genetic linkage map. QTLs detection was conducted by composite interval mapping method in field and disease nursery. [Result] 216 simple sequence repeated (SSR) markers of polymorphism were assigned to 26 Chromosomes with a total map distance of 3 380 cM and an average distance of about 15.77 cM between two adjacent markers. Six QTLs located on 6 chromosomes had been detected and could explain phenotypic variance with 8.56%～20.26%. Five of Six QTLs were consistent with the previous study. Moreover, one novel QTL which located on Chromosome 1 was detected in this study. These results maybe helpful for the marker-assisted development of new cultivars which were resistant to Verticillium wilt. [Conclusion] Six QTLs were detected, one of them is a new QTL on chromosome 1.     

木麻黄水浸液对其幼苗生长的影响

木麻黄防护林存在更新困难,连栽引起生产力下降的问题。采用木麻黄根、新鲜小枝、枯落枝和表层土壤的水浸液处理其幼苗,研究木麻黄他感作用。结果表明,木麻黄各种水浸液对其幼苗生长均起抑制作用,并且随水浸液浓度增大,抑制作用加强。木麻黄不同器官相同浓度的水浸液对幼苗生长的抑制程度表现为根 >新鲜小枝>枯落枝>表层土壤。说明木麻黄更新困难的一个重要原因是木麻黄分泌他感物质抑制自身生长。