Effects of nutrition spatial heterogeneity on root traits and carbon usage by roots of Cercis chinensis seedlings in split root rooms     

GAN Cai-xia  WU Chu 《中国林学(英文版)》2008,10(4)

In natural ecosystems, nutrition available for plants shows great spatial heterogeneity. Much is known about plant root responses to the spatial heterogeneity of nutrition, but little is known about carbon usage in roots in nutrition-deficient patches and its effect on root longevity. In this study, split-room boxes were used for culture of Cercis chinensis seedlings, and the small rooms were supplied with different nutrition levels. The number of the first-order roots in the rooms with nutrition supply was significantly higher than that in the rooms with deficient nutrition. Specific root length (SRL) of the first-order roots in the rooms with deficient nutrition reached its peak at day 64 after nutrition treatment. There was no significant SRL differences between the two order roots during the experiment. Biomass of the first-order roots in the rooms without nutrition supply was significantly less than that of the first-order roots in the rooms with nutrition supply from day 64 to 96. The total biomass of the lateral roots in the rooms without nu-trition supply decreased from day 64 to 96. The activities of the enzymes in roots in the rooms without nutrition supply increased and the activities of alkaline invertases in roots in the two sides of split box did not change significantly. The activities of the enzymes in roots in the rooms without nutrition supply increased gradually. These results suggest that nutrition spatial heterogeneity induced the changes in root traits and plants actively controlled carbon usage in roots in nutrition-deficient patches by regulating the activities of invertases and sucrose synthases, resulting in the reduction in carbon usage in the roots in nutrition-deficient patches.  相似文献   

独行菜LaBBX基因低温表达响应与密码子偏性分析     

周茜  陈芸  王玉州  王继莲  凯迪日耶  玉苏普  赵惠新 《核农学报》2021,35(6):1253-1262

BBX是调控植物非生物胁迫相关基因表达,响应植物逆境胁迫的重要锌指蛋白类转录因子。为探究BBX在独行菜(Lepidium apetalum)幼苗耐受低温生长中的表达响应及其密码子偏好性,本研究基于独行菜转录组数据,筛选独行菜BBX编码基因的cDNA序列,并从独行菜幼苗中克隆获得全长733 bp的基因编码区序列,命名为LaBBX。序列分析表明,LaBBX由242个氨基酸组成,包含2个B-box锌指蛋白结构域,蛋白分子量为61.66 kDa,等电点为5.09,无信号肽和跨膜区。独行菜幼苗受低温胁迫时,LaBBX基因显著上调表达,6 h上调表达至21倍,且24 h内均呈现高水平表达,说明该转录因子可能在独行菜幼苗受低温胁迫时起重要作用。偏好性分析结果显示,独行菜LaBBX基因的ENc、CAI值和GC含量分别为55.453、0.244和46.78%,其密码子使用偏性较弱,相对偏好使用AT,高频密码子有8个,CDS序列及RSCU聚类分析中与十字花科植物最相近;其偏好性的形成与突变和自然选择等诸多因素相关,酵母菌表达系统更适合作为LaBBX基因的异源表达受体,拟南芥是适宜LaBBX基因的遗传转化受体。本研究为了解独行菜LaBBX基因的异源表达及基因功能提供了重要参考。  相似文献   

先张法预应力空心板纵向开裂的防治     

胡晓丰  丁秀芹 《林业科技情报》2007,39(4):82-83

多年来先张法预应力空心板在中、小桥结构物中一直被广泛应用.但在设计回访中发现,部分空心板板底多存在有纵向裂缝的问题,为有效杜绝此弊病的发生,本文对其产生的原因进行了分析并提出了预防措施.  相似文献   

基于采后转录组的香菇密码子偏好性分析     

邓冰  贾鸥阳  杨雨娴  孟俊龙  常明昌  刘靖宇 《保鲜与加工》2022,22(8):8-15

以香菇基因组数据为基础,对其细胞核基因组的密码子偏好性及偏好性形成因素进行分析。香菇细胞核编码基因的GC含量为48.66%,同义密码子第3位中碱基T(T3s)的出现频率最高（36.07%）,同时高表达基因的GC、GC3以及GC3s含量均显著高于基因组水平;相关性分析结果显示基因表达与序列C3s含量、GC3、GC3s、GC含量、C含量以及CAI呈显著正相关;香菇基因组编码序列中共29个高频密码子,结合转录组筛选高表达和低表达基因的基础上鉴定出16个最优密码子;偏好性形成影响因素分析表明,香菇基因组密码子偏好性形成受中性突变和选择压力影响。本研究可以为采后香菇关键基因功能解析,开展香菇采后品质劣变机制研究提供参考。  相似文献   

猪FUT2基因密码子使用偏好性分析及优化     

戴开宇  黄焱杰  吴丽思  包文斌  吴圣龙 《中国畜牧兽医》2018,45(7):1863-1872

为了揭示猪α-（1,2）岩藻糖转移酶2（FUT2）基因密码子使用特性并提高其在外源宿主内的表达量,本研究综合运用EMBOSS Explorer网站和CodonW软件包分析了猪FUT2基因的密码子使用偏好性的相关参数,并与3种模式生物（大肠杆菌、酵母菌和果蝇）基因组密码子使用模式进行比较,最后参照与之最为相近的模式生物基因组密码子使用方式,利用JCat和OPTIMIZER两个密码子优化网站对猪FUT2基因密码子进行优化。结果显示,猪FUT2基因表达水平不高,存在24种偏好密码子,且这24种偏好密码子中有23种以G/C结尾;猪FUT2基因与果蝇基因组密码子使用模式的差异小于大肠杆菌和酵母基因组,表明果蝇更适合猪FUT2基因的外源表达;根据果蝇基因组密码子使用模式优化猪FUT2基因密码子,优化后其适应指数有了明显提高,而整体GC含量没有明显变化,说明在理论上猪FUT2基因优化成功。本研究从翻译水平上揭示了猪FUT2基因的密码子使用特性,为其在遗传改良中选择最佳外源表达系统及提高其在宿主细胞内的表达水平提供一定的理论依据。  相似文献   

保定市开放型绿地空间使用情况调查及对策     

周宁  付晓鹏  杨艳丽  李轩  刘桂林 《北方园艺》2012,(8):87-90

在对保定市区开放型绿地空间的实地调研以及在对游人使用情况调查资料归纳整理的基础上,对保定市的开放型绿地空间存在的问题进行了分析,提出了改进对策,以期今后绿地空间的设计中能充分考虑游人行为特点,使城市绿地空间建设更加符合游人行为特点和需求,最终探索如何营造更适宜人使用的开放型绿地空间类型。  相似文献   

Synonymous codon usage pattern in model legume Medicago truncatula     

Hui SONG  Jing LIU  Tao CHEN  Zhi-biao NAN 《农业科学学报》2018,17(9):2074-2081

Synonymous codon usage pattern presumably reflects gene expression optimization as a result of molecular evolution. Though much attention has been paid to various model organisms ranging from prokaryotes to eukaryotes, codon usage has yet been extensively investigated for model legume Medicago truncatula. In present study, 39 531 available coding sequences (CDSs) from M. truncatula were examined for codon usage bias (CUB). Based on analyses including neutrality plots, effective number of codons plots, and correlations between optimal codons frequency and codon adaptation index, we conclude that natural selection is a major driving force in M. truncatula CUB. We have identified 30 optimal codons encoding 18 amino acids based on relative synonymous codon usage. These optimal codons characteristically end with A or T, except for AGG and TTG encoding arginine and leucine respectively. Optimal codon usage is positively correlated with the GC content at three nucleotide positions of codons and the GC content of CDSs. The abundance of expressed sequence tag is a proxy for gene expression intensity in the legume, but has no relatedness with either CDS length or GC content. Collectively, we unravel the synonymous codon usage pattern in M. truncatula, which may serve as the valuable information on genetic engineering of the model legume and forage crop.  相似文献   

萝藦科观赏植物的应用     

薛秋华  胡莉莉 《勤云标准版测试》2007,(4)

萝藦观赏植物以其花奇特;茎蔓飘逸而倍爱人们亲睐。作者在检索和查阅大量有关植物分类的资料和书籍的基础上,综述了萝藦科观赏植物的种类、形态特征、生态习性和主要用途,并着重介绍此科植物的园林观赏特色、药用价值和经济价值,目的是为开发利用此科观赏植物提供依据。此科植物叶花俱佳,是吊挂和垂直绿化的良好材料。  相似文献   

基于苹果叶片表面自由能的吡虫啉田间减量化研究     

郭瑞峰  张鹏九  刘中芳  樊建斌  范仁俊  高越 《中国果树》2020,(1):64-67,91

研究了苹果叶片-苹果黄蚜-药液三者之间的互作关系,为吡虫啉田间应用减量提供数据支持。通过电镜扫描表征苹果新梢叶片表面结构特性,采用WORK(Owens-Wendt-Rabel-Kaelble)法预测叶片表面自由能,并通过药效试验研究三者之间的互作关系。结果表明:叶片近轴面表面自由能显著高于远轴面,且均以色散分量为主。远轴面和近轴面表面覆盖有大量茸毛,茸毛的密度影响表面自由能。助剂浓度增加,吡虫啉3000倍稀释液的表面张力由42.72 mN/m下降到22.87 mN/m,药后3 d对苹果黄蚜的田间防效由80.27%上升到94.25%。苹果新梢叶片近轴面和远轴面属于疏水表面,易被以色散分量为主的非极性溶剂润湿。当喷雾药液的表面张力值接近于苹果新梢叶片表面自由能值时,药液易铺展润湿。吡虫啉防治苹果黄蚜时,喷雾药液表面张力应为20~30 mN/m。  相似文献   

对广东省造林工程实施招投标制度的思考     

姜杰  徐雪松  邓洪涛 《林业调查规划》2015,40(1):129-132

回顾广东省造林工程概况,分析林业行业及造林工程特点以及当前导致造林质量不高、综合成效较差等问题的主要原因。造林工程实施招投标制度有利于提高造林资金使用效率,提升行业经营管理水平,形成公平公正的竞争秩序。为此,提出尽快出台相关管理办法,简化招投标程序,重视专业人员培养和监督管理等广东省造林工程实施招投标制度的建议。  相似文献