Effect of soil microorganisms on the growth of roots in rice seedlings

Abstract

Root system of rice seedlings grown on nutrient solution inoculated with soil microorganisms were examined morphologically in comparison with those obtained under sterile condition. In the presence of soil microorganisms, primary roots increased in their number and decreased in the total length. Inoculated plants had more secondary roots equipped with tertiary roots. In addition, longer root hairs developed densely on primary and secondary roots of the inoculated seedlings.

Anatomical examination of the primary roots revealed that the number and width of cortical layers, as well as the length and width of the cortical cells, were increased by the effect of microorganisms. Microbial effect on outer morphology of rice roots, consequently, was estimated to have been induced from the alteration in histological and cytological activities including the activation of the periclinal divisions of the epidermal cells, the inactivation of the transverse divisions of the cortical cells and the activation of the elongation of cortical cells.     

Responses of Parkia biglobosa (Jacq.) Benth, Tamarindus indica L. and Zizyphus mauritiana Lam. to arbuscular mycorrhizal fungi in a phosphorus-deficient sandy soil

Responses of three multipurpose fruit tree species, Parkia biglobosa (Jacq.) Benth, Tamarindus indica L. and Zizyphus mauritiana Lam., to inoculation with five species of arbuscular mycorrhizal fungi, Acaulospora spinosa Walker and Trappe, Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, Glomus intraradices Schenck and Smith, Glomus aggregatum Schenck and Smith emend. Koske and Glomus manihotis Howeler, Sieverding and Schenck, differed markedly with respect to functional compatibility. This was measured as root colonization, mycorrhizal dependence (MD) and phosphorus concentrations in shoots of plants. Root colonization of fruit trees by A. spinosa, G. aggregatum and G. manihotis was high and tree growth increased significantly as a consequence. G. intraradices also colonized well, but provided little growth benefit. G. mosseae colonized poorly and did not stimulate plant growth. The MD of P. biglobosa and T. indica was similar, reaching no more than 36%, while Z. mauritiana showed the highest MD values, reaching a maximum of 78%. The Z. mauritiana A. spinosa combination was the most responsive with respect to total biomass production; phosphorus (P) absorption probably contributed to this more than the absorption of sodium, potassium, magnesium or calcium. The density and length of root hairs were positively correlated with MD, suggesting that root hairs are not indicative of MD. Received: 20 January 1997     

陆地棉纤维品质性状的遗传力和显性度——1980—1985年估测结果综述

本文总结了1980—1985年间测定的陆地棉纤维长度、整齐度、纤维细度、纤维捻曲度、纤维强度、断裂长度等主要纤维品质性状的广、狭义遗传力(h_B~2·h~2)和显性度(H/D)~(1/2)的估值;结果显示这些性状大多具有中、低等遗传力,广狭义遗传力估值差异不大;这些性状的显性度,除纤维细度在6次测定中有1次达到1.55、断裂长度在1次测定中达到1.01以外,其余都在1.00以下,表明这几种性状大多属于部分显性,杂种优势不强。本文还对在估算遗传力估值中产生的偏倚进行了讨论,对在估算遗传参数中增加样本数和加强地区之间的协作,提出了建议。     

当代中国新阶层阶层意识的朦胧与觉醒

改革开放以来,我国的社会结构发生了深刻变化,出现了许多新的社会阶层,新阶层又逐渐产生了阶层意识。这些新阶层的阶层意识目前尚处于自发和朦胧状态,远未形成整体意义上的共同阶层意识和整体的社会责任,共同的阶层意识对社会主义现代化建设意义重大,我们应着力培育和健全他们共同的阶层意识。     

浦东白猪毛色的遗传基础研究——KIT基因变异的检测

浦东白猪是国内唯一一个毛色全白的地方猪种。但是对其毛色全白的分子遗传基础,迄今一直无人研究。为此,本研究通过聚合酶链式反应-单链构象多态性分析（PCR—SSCP）以及对KIT基因内含子17和内含子18的测序探讨了浦东白猪白毛色的遗传控制体系与长白猪和大白猪白毛色控制体系的异同。结果证明,浦东白猪与长白猪和大白猪一样。其白毛色均为KIT基因内含子17发生了G—A的突变,内含子18的序列中存在AGTT的缺失造成的。     

牛尾毛中稳定性碳同位素组成变化规律研究

 【目的】研究牛尾毛中稳定性碳同位素组成随饲料改变的变化规律,确证牛尾毛一旦长成,其中的稳定性碳同位素不再与其它部分的进行交换,每段毛发记录的同位素信息可反映毛发生长时的饲料信息。【方法】设计控制饲料配比的牛模型试验,利用同位素比率质谱仪测定不同段位牛尾毛中的δ13C值,分析不同段位牛尾毛的δ13C值随饲料改变的变化趋势,以及牛尾毛中的δ13C值与饲料、牛个体的关系。【结果】随着牛生育过程中饲料成分的改变,不同段位牛尾毛中碳同位素组成有极显著差异,而且饲料对牛尾毛中碳同位素组成的影响远大于个体对其的影响;分段取得的牛尾毛δ13C值与其饲料δ13C值、C4植物饲料比例呈极显著相关（P＜0.01）,而不分段的牛尾毛δ13C值与饲料碳同位素组成相关性不显著。【结论】牛尾毛一旦长成,其中的稳定性碳同位素不再与其它部分进行交换,每段毛发的同位素信息可反映牛在毛发生长时的饲料信息,牛尾毛可以看作是记录牛饲料改变信息的档案库。     

影响羊毛生长的主要因素研究综述

羊毛的生长受很多因素的影响,毛囊的性状和皮肤组织结构决定着羊毛的品质和产量。对影响羊毛生长的主要因素作了阐述。     

中华绒螯蟹触角及复眼在觅食行为中的作用研究

用硝酸纤维素分别对河蟹的触角和复眼进行涂膜处理，以观察第一、第二触角及复眼在觅食行为中的作用，并对第一、第二触角及复眼作了电镜扫描。观察结果，初步认为幼蟹触角对寻找食物的定位起主要作用，化感器较多地分布于第一触角，而复眼在觅食中作用不明显。     

绒山羊毛囊干细胞的分离培养及诱导分化鉴定

试验旨在建立绒山羊毛囊干细胞体外分离培养方法,并对其生物学特性和多向分化潜能进行鉴定。利用两步酶消化法和差速贴壁法分离纯化毛囊干细胞,对其进行传代培养,测定生长曲线和克隆形成率,采用油红O和茜素红染色法对第5代毛囊干细胞向成脂和成骨分化情况进行鉴定。结果显示,分离得到的毛囊干细胞形态均一,体积小,呈典型的铺路石状生长,生长曲线呈S型,克隆形成能力强。成脂诱导后,细胞体积增大,细胞质增多,胞内出现小脂滴,诱导12 d后,脂滴逐渐增多,油红O染色呈阳性;成骨诱导后,细胞边缘模糊,出现颗粒状结节,经茜素红染色呈阳性。表明获得的绒山羊毛囊干细胞具有多向分化的潜能。