秀山湾兰多维列末期胞石成种与特型

特型包括形态特型和大小特型。特型是特殊环境的产物。随着温度上升、海水粘度下降,迁入并被隔离于温（盐）跃层内的Ａｎｇｏｃｈｉｔｉｎａｌｏｎｇｉｃｏｌｉｓ产生成种作用。Ｌａｍｂｄａｃｈｉｔｉｎａｂｉｐｅｄａｔａ和Ｌ．ｓｙｎａｐｈａｃａｎｔｈａ减少体积、增加表面积而上浮;Ａｎｇｏｃｈｉｔｉｎａｓｐ．增加体积而下沉：各自开发空生态灶。前者采取了ｒ策略,后者采取Ｋ策略。本文支持胞石是后生动物卵的卵囊的观点,认为：侏儒是按发育程序,但提前孵化的卵的卵囊,巨型是直接孵化（超期孵化）的卵的卵囊。Ａ．ｓｐ．的形态改变通过细胞分裂超期和加速而实现。成种作用产生的新生分子的形态和大小为空生态灶的容量和位置所渠导,具有明显的方向性。     

Amperometric biosensors based on dehydrogenase/NAD and heterocyclic quinones

The electrocatalytic oxidation of NADH was evaluated from cyclic voltammetry with heterocyclic quinones dissolved in a water solution. The process of oxidation is not sensitive to the nature of the electrode surface and takes place on platinum, glassy carbon or carbon electrodes. NADH and glucose sensors constructed were investigated and operated at 0 mV vs. Ag/AgCl (in saturated KCl) using single potential step chronoamperometry.     

反式激活HIV—1LTR的人疱疹病毒6型（HHV—6）基因片段的初步研究

艾滋病（ＡＩＤＳ）主要是由人免疫缺陷病毒（ＨＩＶ）侵入人体后,破坏人的免疫系统造成的。许多流行病学研究已证明,疱疹病毒与ＨＩＶ的共感染可以导致对ＨＩＶ－１启动子的激活,并加速细胞的病理性反应〔１〕,从而加大个体对ＨＩＶ感染的敏感和加快疾病的进程。人疱...     

黑腹果蝇单胚培养技术的建立

过硬单胚培养十一项特殊的技术,运用此技术可以从果蝇单个原肠胚（同一基因型）中提取细胞进行体外培养,科观察到各种细胞的分化过程,从而能研究导致发生异常或致死突变的机制。通过反复摸索实验,我们在本实验室的条件下,建立了黑腹果蝇（D. melanogaster）单胚培养技术,并对野生型（Canton special, CS.）果蝇的单胚细胞进行体外培养,观察到了各种细胞,如肌肉细胞、神经细胞、脂肪细胞、以及成虫盘等的分化及其发生规律性,为今后研究突变奠定了基础。实验过程中,我们采用了载玻片法和培养皿法。两种方法各有特点及利弊,本文一并进行讨论。Abstract:We can culture the cells of single gastrula (the gene type of cells is same) in vitro,we now have cstablished the technique of single embryo culture in Drosophila.We have seen the differentiated state of myocytes, neurocytes,hemocyte cells,epithelical cells and imagical disk by this technique.     

因子Ⅷ基因突变的研究进展

凝血因子Ⅷ（FⅧ）是内源性凝血系统中一重要的辅助因子,由于基因缺陷而引起的Ａ型血友病是一种常见的遗传性出血性疾病.近几年来,由于FⅧ基因的阐明及成功的表达,从而使其基因突变的研究得以深入而广泛地展开.文章对这方面最新的研究进展及其采用的新技术作了较全面的介绍,这是迄今遗传性疾病基因缺陷研究中最深入、最完整的一个范例.     

Influence of the exclusion distance among trees on gap fraction and foliage clumping index of forest plantations

Key message

A hypergeometric model is proposed explicitly instead of two previous stochastic models (the Poisson model and Neyman-A model) to describe the topological relationship of trees and the influence of the exclusion distance on gap fraction and clumping index of forest plantation canopies.

Abstract

Gap fraction (GF) and clumping index (CI) play key roles in plant light interception, and therefore they have strong impacts on plant growth and canopy radiative transfer processes. Trees are usually assumed to be randomly distributed in natural forests in many previous studies. However, few studies have shown how trees are distributed in forest plantations and how these distribution patterns affect GF and CI in these forests. In this paper, a simple and general distance factor defined as relative allowable shortest distance between centers of two adjacent crowns divided by the mean diameter of the crowns (RASD) is proposed to describe quantitatively the degree of mutual exclusion among trees in forest plantations of various tree distribution patterns. A hypergeometric model is proposed instead of two previous stochastic tree distribution models (the Poisson model and Neyman-A model) to describe the topological relationship of trees and the influences of the exclusion distance on the GF and CI of the forest plantation canopies. The results show that: (1) the hypergeometric model is more suitable than the Poisson model and Neyman-A model for describing the topological relationship of trees in forest plantations; (2) the exclusion distance has strong impacts on GF and CI: there are significant differences between the results of the hypergeometric model and the Poisson model. Larger RASD causes lower GF and larger CI. The simulations are verified by field measurements in four forest plantation stands. Similarly, impacts of RASD on GF and CI are also found for other two crown shapes (prolate and oblate ellipsoids).