Immunohistochernical localization of IAA in graft union of explanted internode grafting

The dynamic changes of IAA in graft union of explanted internode autografting of Cucumber (Cucumis sativus Linn.) have been investigated using the immunohistochemical localization technique. It is shown that the efficiency of IAA fixation using lyophilization-gas fixation is higher than that using liquid chemical fixation. In contrast to few silver particles and no significant changes during the development of graft union cultured in hormone-free medium, more silver particles in graft union and significant changes of IAA related to graft union development have been found when graft union was cultured in medium supplemented with appropriate hormones. The fixation procedure of plant hormones and the roles of IAA in graft union are discussed.     

Expression ofbcl-2 gene increases in apoptosis of vascular endothelial cells induced by rattlesnake venom

Apoptosis of vascular endothelial cells (VEC) has been induced by deprivation of survival factors (aFGF and serum) and by rattlesnake venom. The expression ofbcl-2 gene has been examined by Northern blotting in the two apoptosis inducing systems. Our results show that the expression ofbcl-2 has not been detected in normal culture cells and in apoptotic cells induced by deprivation of survival factors. But in apoptotic cells induced by rattlesnake venom (10 ng/mL), the expression ofbcl-2 increases, and its mRNA exhibits two bands. The data first suggest that increasing expression and splitting ofbcl-2 mRNA may play an important role in apoptosis of VEC induced by rattlesnake venom, and this finding is helpful to understanding the role ofbcl-2 in regulation of apoptosis.     

Relationship between echolocation frequency and body size in two species of hipposiderid bats

Frequencies of echolocation calls with maximum power of Himalayan leaf-nosed bats and Horsfield’s leaf-nosed bats during searching phase were 74.1 and 92.1 kHz, respectively. Head-body length, forearm length and body mass of Himalayan leaf-nosed bats were 82.9 mm, 89.7 mm and 59.1 g, respectively; and the corresponding values of Horsfield’s leaf-nosed bats were 68.4 mm, 61.3 mm and 19.7 g, respectively. Echolocation frequency and the three parameters of body size, head-body length, forearm length and body mass, were all negatively correlated, and the correlation coefficients were −0.86, −1.58 and −2.19, respectively. This study thereby proved that echolocation frequency and body size were negatively correlated in the two species of hipposiderid bats.     

基于微量分析的沉积物-水界面磷铁相关性研究

为了更好地控制和治理湖泊富营养化,探究沉积物-水界面中磷和铁的相关性特征。通过室内培养原位沉积柱,利用微界面分析技术和高分辨率平衡式间隙水采集技术(HR-Peeper),分3时段(加入摇蚊幼虫后的第7天、第21天和第35天),探究好氧环境中摇蚊幼虫扰动与铁的氧化耦合作用下沉积物-水界面体系中磷形态的迁移转化规律。研究结果表明:摇蚊幼虫扰动增加了沉积物中氧气的渗透深度和氧化还原电位E_h值,在第21天扰动最激烈;扰动降低了3个时段沉积物间隙水中的溶解态磷SRP(最大58%)、溶解态铁Soluble Fe(Ⅱ)(最大44%)的浓度;SRP与Soluble Fe(Ⅱ)在第7天和第21天也高度相关。可见,摇蚊幼虫的扰动作用所引起的沉积物中磷的变化受到了铁的氧化吸附控制。     

红树林广州小斑螟发生与气象因子的关系研究

气候是红树林虫害的重要影响因素之一。为探明气象要素与红树林虫害发生程度的关系,本文以广西北海红树林最常见的虫害——广州小斑螟（Oligochroa cantonella Caradja）为切入点,基于2004-2015年灾情面积数据及气候资料,采用Pearson相关分析法,分别于月尺度和旬尺度上筛选与广州小斑螟发生程度显著相关的关键气象因子及影响时段。结果表明研究区域内广州小斑螟的发生显著受2月上旬环境条件的影响,并与风速、降水量及温湿系数呈正相关,与日平均气温呈负相关。研究结果将为红树林广州小斑螟虫害防治预警提供技术支撑。     

广西崇左叉叶苏铁野生和迁地保护种群的遗传多样性比较分析

叉叶苏铁[Cycas bifida （Dyer） K.D.Hill]为国家一级重点保护野生植物,了解广西崇左叉叶苏铁野生种群和迁地保护种群的遗传多样性和遗传结构,可为其种质资源的保护及管理提供指导。本研究利用筛选得到的6对稳定且多态性良好的Simple Sequence Repeat （SSR）引物,对位于崇左的4个叉叶苏铁野生种群和迁至桂林的1个叉叶苏铁迁地保护种群共109个个体的遗传多样性和遗传结构进行分析。结果表明： 4个野生种群的观测等位基因数平均值为2.875,有效等位基因数平均值为1.796,Shannon信息指数平均值为0.637,观测杂合度平均值为0.363,期望杂合度平均值为0.373,说明广西崇左叉叶苏铁遗传多样性水平较低。迁地保护种群的观测等位基因数、有效等位基因数、Shannon信息指数、观测杂合度和期望杂合度分别为3.000、1.865、0.686、0.323和0.391,说明迁地保护能提高叉叶苏铁遗传多样性。遗传结构中群体间遗传呈中度分化（0.134）,种群间遗传变异占25%,种群内遗传变异占75%,遗传变异主要来源于种群内。非加权组平均法（Unweighted Pair-Group Method with Arithmetic means,UPGMA）、主坐标分析（Principal Co-ordinates Analysis,PCoA）和Structure分析表明109份样品可分为2类,迁地保护种群ZWS和野外种群PR为一类,其余3个种群为一类。野生种群中MALL的群体遗传多样性最高（Shannon信息指数为0.711,期望杂合度为0.394）,应将该种群作为重点保护单元进行保护。迁地保护种群ZWS的Shannon信息指数和期望杂合度均高于野生种群平均值,但Shannon信息指数略低于野生种群MALL,期望杂合度略低于野生种群MALL和YCLL。建议继续加强野生种群MALL和YCLL种群资源的引种工作,以便更有效地保护叉叶苏铁的遗传资源。