Mechanical Signalling in Plant: Perception and Transduction Pathway

The metabolism and development of plants are controlled through interplay between genetic and environmental cues.For optimal growth plants require the ability to coordinate complex developmental processes and at the same time sense and respond to environmental stimuli.The responses can be divided into three main events: stimulus perception,generation and transmission of a signal,and subsequent changes in downstream biochemical processes.Because of space limitation this review does not provide an exhaustive account of plant signal transduction.Rather,the authors intention is to cover new and important results in this field,including the mechanochemical transform mediated by integrin and integrin-like protein,the change of membrane fluidity respond to stimulus,and the wide accepted transduction pathway of calcium signaling system.The research emphasis and tendency are prospected.     

花粉管通道法转化大豆的分子表征

采用花粉管通道技术将含有gus基因的pBI121质粒DNA导入辽豆14，从处理的100朵花中获得53粒种子。经PCR检测53粒种子的幼苗，共检测出6株阳性植株。采用RT—PCR和GUS组织化学染色法对所获得阳性植株进行检测，其中2株幼苗(T0代17号和33号)均出现阳性结果，进一步对这2株阳性植株进行Southern blot检测，同样获得了阳性结果。上述检测结果表明，gus基因已整合到染色体上并得到了表达。对转基因植株后代进行了PCR跟踪检测，结果从17号株系的28株中检测出19株阳性植株，33号株系的35株幼苗中检测出17株阳性植株，表明gus基因可以在转基因植株后代遗传。本研究结果为大豆花粉管通道转化技术提供了比较充分的分子生物学证据。     

Discovery of a new gene causing dark green cotyledons and pathway of pigment synthesis in lentil (Lens culinaris Medik)

A new gene is reported which functions as a master gene for synthesis of the pigments determining cotyledon colour in lentil. This gene is different from the two earlier reported genes which are responsible for synthesis of yellow (gene Y) and brown (gene B) pigments. Double recessive homozygous condition of these two genes results into loss of both pigments and, consequently, produces light green cotyledons. The new gene, in contrast, produces dark green cotyledons in recessive condition irrespective of the dominance or recessive state of the Y and B genes. It is hypothesized that the new gene for dark green cotyledon colour (Dg) acts at an earlier stage in the biosynthesis of the two cotyledon-specific pigments, which are derived from a common precursor, whose synthesis is blocked when Dg mutates to its recessive condition. This revised version was published online in August 2006 with corrections to the Cover Date.     

利用花粉管通道法将兔防御素NP-1基因导入小麦的研究

兔防御素NP-1是抗性谱最广的防御素之一。为提高小麦的抗病虫能力,培育优质高抗的小麦品种,采用花粉管通道法将兔防御素NP-1基因导入优质小麦品种G8901。对得到的193株T0植株进行抗除草剂筛选,获得4株抗性植株。通过PCR及PCR-Southern杂交,证实了NP-1基因已经整合到转基因植株的基因组中,并稳定遗传到T1。田间抗病虫鉴定结果表明,这些植株对于白粉病、叶锈和条锈病有较强的免疫力和抗性,但对于蚜虫的抗性没有明显提高。     

Relationship between molecular characteristics of soil humic fractions and glycolytic pathway and krebs cycle in maize seedlings

A humic acid (HA) isolated from a volcanic soil was separated in three fractions of decreasing molecular size (I, II and III) by preparative high performance size exclusion chromatography (HPSEC). The molecular content of the bulk soil HA and its size fractions was characterized by pyrolysis-GC-MS (thermochemolysis with tetramethylammonium hydroxide) and NMR spectroscopy. All soil humic materials were used to evaluate their effects on the enzymatic activities involved in glycolytic and respiratory processes of Zea mays (L.) seedlings. The elementary analyses and NMR spectra of the humic fractions indicated that the content of polar carbons (mainly carbohydrates) increased with decreasing molecular size of separated fractions. The products evolved by on-line thermochemolysis showed that the smallest size fraction (Fraction III) with the least rigid molecular conformation among the humic samples had the lowest content of lignin moieties and the largest amount of other non-lignin aromatic compounds. The bulk HA and the three humic fractions affected the enzyme activities related to glycolysis and tricarboxylic acid cycle (TCA) in different ways depending on molecular size, molecular characteristics and concentrations. The overall effectiveness of the four fractions in promoting the metabolic pathways was in the order: III>HA>II>I. The largest effect of Fraction III, either alone or incorporated into the bulk HA, was attributed to a flexible conformational structure that promoted a more efficient diffusion of bioactive humic components to maize cells. A better knowledge of the relationship between molecular structure of soil humic matter and plant activity may be of practical interest in increasing carbon fixation in plants and redirect atmospheric CO₂ into bio-fuel resources.     

多路径下桃园射频信号传输特性

为解决无线传感器网络在桃园中的快速部署问题,该文研究了2.4 GHz无线射频信号在桃园中的传播特性。依据角度选取4条传输路径,在3种(0.5、1.5、2.5 m)典型的天线高度,同时测量丢包率和路径损耗情况,分析表明两者具有明显的相关性,天线高度和通信距离是路径损耗的主要影响因素。在天线高度为0.5和1.5 m时,可靠传输距离为6个行距(27 m);在天线高度为2.5 m时,可靠传输距离大于14个行距(63 m),因此冠层顶部为布设天线的最佳位置。对路径损耗数据进行回归分析,发现其在每种天线高度,每条传输路径下对数模型最适合作为路径损耗模型,模型的R2最大为0.945,最小为0.732。为研究节点部署于桃园任意位置时的路径损耗情况,便于节点快速灵活地部署,在3种天线高度下对路径损耗数据进行对数回归分析,R2最大为0.976,最小为0.939。最后对2组模型进行了验证,表明模型可以预测射频信号在桃园中的路径损耗情况,该文研究结果为无线传感器网络在桃园中的部署提供了参考。     

籽鹅促卵泡激素β亚基cDNA的分子克隆与序列分析

从新屠宰的雌性籽鹅脑垂体中提取总RNA,经RT-PCR法扩增目的片段,获得长为396 bp的籽鹅促卵泡激素β亚基cDNA片段。将扩增的片段与pMD18-T载体连接,并转化至DH5α感受态细胞中。随机挑选阳性重组子进行鉴定、测序,将测序结果与绵羊、水牛、鸡、鸭等多种哺乳动物和禽类该基因序列及相应氨基酸序列进行同源性分析。结果显示,籽鹅促卵泡激素β亚基基因序列和其它动物一样,都有较高的保守性。其中与鸭的同源性最高,核苷酸同源性为97.0%,氨基酸同源性为100%。总体来看,在各种动物中FSHβ亚基基因同源性是很高的。     

农用地分等中产量比系数求算方法的研究

对现行《农用地分等规程》中产量比系数计算方法进行探讨,寻求产量比系数的最佳求算方法;研究结果表明《规程》中产量比系数的算法使得研究区冬季作物的自然质量等指数偏大,与实际不符;按两套产量比系数计算的结果则不存在这一问题;建议在农用地分等中,种植制度为一年两熟的地区应分冬夏设两个基准作物,分别编制冬季播种作物和夏季播种作物的产量比系数。