中国普通野生稻遗传分化的RAPD研究

多数学者已认定亚洲栽培稻（ＯｒｙｚａｓａｔｉｖａＬ．）的祖先是普通野生稻（Ｏ．ｒｕｆｉｐｏｇｏｎ）。然而栽培稻的籼、粳分化是发生在驯化之前还是在驯化之后,也即普通野生稻是否存在籼、粳分化的问题,是十几年来稻作起源研究中争论的热点之一。Ｓｅｃｏｎｄ［１］用多个同工酶位点的分析结果得出结论,普通野生稻在驯化为栽培稻之前就已经发生了籼、粳分化,即有籼型普通野生稻和粳型普通野生稻之分。Ｍｏｒｉｓｈｉｍａ和Ｇａｄｒｉｎａｂ［２］用２４个形态和生理性状及１２个同工酶位点和杂交亲合力等方法证明普通野生稻没有发…     

Diurnal variations of amino acids and organic acids in xylem fluid from Lagerstroemia indica: an endogenous circadian rhythm

Diurnal variations in the concentrations of major organic compounds occurred in xylem fluid extracted from Lagerstroemia indica L. The concentration of amino acids and the N/C ratio was at a maximum and that of organic acids was at a minimum between 1230 and 2030 h. Since the concentrations of total organic nitrogen, total amino acids and most individual amino acids (but not organic acids or sugars) were also proportional to xylem tension two experiments were performed to discern whether variations in chemistry were a consequence of diurnal changes in moisture stress. In the first experiment, L. indica , exposed to variable levels of moisture stress during midday, manifested an increase in organic acids and a reduction in the N/C ratio. In the second experiment, chemical profiles of xylem fluid were collected and compared for plants exposed to a natural photoperiod, constant darkness or continuous light at noon and midnight. After 1 day amino acids increased in concentration during midday for all treatments; the variation was greatest (10-fold) for plants in constant darkness where xylem tension varied from 0.20 to 0.25 MPa. Only plants exposed to continuous light lost a diurnal rhythm after 3 days. Thus, the circadian rhythm was endogenous, terminated in continuous light and was not mediated by changes in moisture stress. Glutamine accounted for most of the diurnal variation in total amino acids, organic nitrogen and the N/C ratio in xylem fluid.     

RESEARCH ON INSECTICIDES FROM PLANTS IN CHINA

Abstract  An overview is presented on recent (1989–19911 investigations on insecticidal plants in China, specially in South China. The main emphasis was laid on studies of Meliaceae including Azadirachta indica, Melia azedarach and M. toosendan , as well as on Rhododendron molle, Derris elliptica, Tephrosia voglii, Ajuga nipponensis, Plumbago idea and Celastrus anplatus . Research work on the bioactivities and application of essential oils from plants for the control of stored-grain insects is also discussed. The results of these investigations reveal a great potential of the active ingredients of a number of Chinese plants for integrated pest management, as well as for using these natural product models as guides for the synthesis of a novel class of insecticides.     

了哥王叶功能性状特征及其对土壤因子的响应

为探究了哥王Wikstroemiaindica的叶功能性状特征及其影响因素,在海岛植被调查的基础上对了哥王叶片进行取样并测定其功能性状指标,利用变异系数法和Pearson相关性分析探讨叶功能性状之间的差异与联系,运用冗余分析研究了哥王叶功能性状对土壤因子的响应。结果表明,了哥王的叶功能性状变异系数介于9.76%～23.73%,其中叶体积变异幅度最大(23.73%),叶干物质含量变异幅度最小(9.76%),整体上了哥王叶功能性状保持相对稳定。了哥王各项叶功能性状之间具有一定的相关性,联系较密切。了哥王叶功能性状主要受土壤中有机质、全氮、碱解氮的影响,土壤中有机质、全氮、碱解氮的含量与比叶面积呈正比,与叶厚度、叶体积成反比。了哥王的叶片可以通过一定的性状变异和组合来适应外部环境的变化,以较好地适应海岛恶劣的环境。该研究结果可为了哥王野生种质资源的保护、利用以及人工栽培提供参考。     

板齿鼠种群数量中长期预测的时间序列模型

本文利用时间序列方法（三次指数平滑法）,并结合季节指数法,建立了板齿鼠种群数量中长期预测（６个月～１年）的时间序列模型,依据１９９１年１１月～１９９３年１２月在广东省博罗县石湾镇里波水管理区对板齿鼠种群数量动态的调查数据,分别预测了１９９４年和１９９５年板齿鼠种群数量的发生,预测准确率达到了８６．５６％。     

不同育秧方式和插植密度下晚籼稻群体动态结构的研究

不同育秧方式和插植密度下晚籼稻群体动态结构存在差异。旱育秧群体分蘖速度快,分蘖能力强。稀植可促进个体分蘖多发、有效穗数增多,但旱育稀植并无分蘖早发的优势。旱育稀植使主茎基部叶片变短而上部叶片变长,生育后期叶面积消长平稳,地上部干物质积累较多。旱育秧、稀植都使主茎叶总数增多,全生育期延长。     

Wenyonella baghdadensis sp. n. from the Bandicoot Rat Nesokia indica in the Baghdad Area

SYNOPSIS. Oocysts of Wenyonella baghdadensis sp. n. were found in the feces of 2 of 12 bandicoot rats Nesokia indica Gray & Hardwicke from the Baghdad area. Sporulated oocysts were subspherical to broadly ellipsoidal, 25.4 (18–22) × 20.8 (15–28) μm, with a 2-layered wall, the outer wall being mammillated, without micropyle, micropylar cap, residuum, or polar granule. Sporozoites were ovoid, 11.8 (9–15) × 8.4 (6–10) μm, with Stieda body and residuum. Two sporozoites in each sporocyst were elongate, with granular cytoplasm and a refractile globule, the other 2 were bean-shaped, without granules or refractile globule. Sporulation time equalled 3 days at 22–24 C. Entamoeba coli and Giardia sp. cysts were also found in 3 rats each.     

A procedure for regenerating Japonica and Indica varieties of rice from protoplasts

Fertile rice plants have been regenerated from protoplasts of two japonica rice varieties (Radon and Baldo) using a protocol initially developed for plant regeneration from protoplasts of an indica rice. Embryogenic calli were developed from immature embryos of Radon and Baldo rice on a callus induction medium, and then used to establish cell suspensions. Protoplasts were isolated from the cell suspensions, and cultured on a Millipore filter placed on a Kao/agarose medium that contained cell clusters from suspensions of IR52 or IR45. The protoplasts grew vigorously on Kao medium and developed into embryogenic calli within two to three weeks. Somatic embryo development occurred during a subsequent transfer of the calli to an LS medium for two to three weeks. The calli were then transferred to MS or N6 plant regeneration medium, and within one to three weeks, plants regenerated from 21 to 32% of the Radon calli, and 33 to 35% of the Baldo calli. Based upon these results and the previous success in regenerating an indica variety from protoplasts, this procedure has great promise for regenerating a range of rice varieties, and probably for regeneration of other monocotyledonous plants from protoplasts     

Studies on north indian volvocales-III. Fertilization in Eudorina californica (shaw) goldstein

The present communication deals with the details of sexual reproduction including the process of fusion of gametes in Eudorina californica (Shaw) Goldstein (earlier described as E. indica lyengar). The present observations are compared with those on other species in which the process of fusion was recorded.