4种地被竹生理指标对低温的响应

以铺地竹、黄条金刚竹、菲白竹、鹅毛竹4种地被观赏竹为试验材料,测定了自然降温条件下4种地被观赏竹的质膜透性、SOD、POD、MDA、叶绿素含量等生理生化指标的变化,分析了4种地被竹对低温胁迫的响应情况.结果表明:随着外界温度逐渐下降,叶片的细胞质膜透性呈上升趋势,但竹种间上升幅度不同,菲白竹、铺地竹、鹅毛竹、黄条金刚竹的半致死温度分别为-11.53℃、-4.25℃、-13.74℃、-8.73℃.SOD呈现出与电导率相似的变化趋势.当气温降到0℃以下,POD上升速度较快,在12月22日(-7.9℃)温度最低时,POD到达最大值,之后开始下降.随着气温的降低,叶片MDA变化呈上升趋势,菲白竹的上升幅度最小.温度与电导率、MDA、SOD、POD间均呈负相关,与电导率相关性最大,相关系数为-0.865.     

梨矮化砧木中矮1号GA20-氧化酶基因克隆与表达分析

中矮1号是中国农业科学院果树研究所选育的梨优良矮化砧木,为研究其矮化机理,利用RT-PCR结合RACE方法克隆了梨矮化砧木中矮1号的1个GA20-氧化酶基因,并对该基因及其氨基酸序列以及该基因在不同生长类型梨品种中不同时期新梢叶片中的表达进行了分析。结果表明,该基因全长1 179 bp,推导编码392个氨基酸,其编码的...     

Early-stage impacts of sika deer on structure and function of the soil microbial food webs in a temperate forest: A large-scale experiment

Modification of forest vegetation caused by an overabundance of mammalian herbivores has been reported in temperate and subarctic regions all over the world. However, the indirect effects of these herbivores on the structure and functions of soil decomposer systems are not fully understood, especially in temperate forests. We investigated the early effects of sika deer invasion on soil decomposer systems in a Japanese temperate forest using two large-scale experimental enclosures with low and high densities of deer (LD: 25 ha, 4 deer km⁻²; HD: 6.25 ha, 16 deer km⁻²) including control plots without deer (WD). Three years after deer introduction the understory cover of dwarf bamboo (Sasa nipponica) declined due to deer browsing in both enclosures. At the same time, measurements were made of the soil microbial community, soil nematode community, soil nitrogen (N) mineralization rate, and carbon (C) and N content in dwarf bamboo leaves. In LD, soil microbial biomass was lower from WD, probably due to the decrease of fresh aboveground litter from dwarf bamboo. Surprisingly, there were no cascading effects on total abundance of soil nematodes and soil total N mineralization potential which were unaffected by deer in the LD treatment, while soil NH₄⁺-N content was lower and soil nematode community structure was different (abundance of 4 families was higher and that of 3 families was lower, but the functional structure was not different) from WD. Specifically, the responses to deer introduction varied between microbes and nematodes, and the change of balance in the microbial food webs may have altered N mineralization processes. In contrast, in the HD treatment, all the variables measured were not significantly different from those of WD treatment. Intensive browsing by deer may have cancelled out the effects of the decrease in aboveground litter input on the soil decomposer systems through other pathways, such as a transitory increase in belowground litter input caused by induced changes in allocation patterns of bamboo. No changes in total N mineralization potential, leaf N, and composition of understory vegetation in both enclosures indicated that deer introduction did not facilitate nor retard N cycling regardless of deer density. This study showed that sika deer browsing can affect soil decomposer systems at an early stage of invasion even at low density, which contrasts with previous studies on the subject. Linking our findings of early-stage effects of deer on soil decomposer systems to longer-term dynamics of understory vegetation and tree regeneration will be needed to evaluate the adequacy of deer management practices with respect to the sustainability of soil nutrient supplies.     

不同处理方式对早期生长势弱草花种苗的影响

草花在园林景观利用的地位越来越来高,草花生产育苗技术是关键环节。有些草花种苗早期生长势较弱,导致种苗易倒伏,生长受影响,对生产高质量的草花种苗有制约。试验采用三种方法：直接平盘育苗、提前分穴盘、矮化处理,力求解决草花早期生长势弱的问题。结果表明：提前分穴盘有利于种苗生长,提高种苗质量。     

中矮1号梨砧木(S_2)PGIP基因的克隆及序列分析

利用RT-PCR技术,根据GenBank中梨属PGIP基因序列设计1对特异引物,以梨矮化砧木S2叶片总RNA为模板,克隆到1条约1100bp的cDNA片段,将其与pMD18-Tvector连接后转化Escherichia coli JM109,对筛选到的阳性克隆进行序列测定并使用生物信息学方法对所得结果进行综合分析。结果表明,克隆片段为梨PGIP基因,该cDNA编码330个氨基酸,预测分子量为36388ku,第1～24个氨基酸残基是信号肽。与梨属其它种中已获得的PGIP核苷酸序列开放阅读框(Open reading frame,ORF)的同源性为97.5%～99.6%,氨基酸序列的同源性为97.6%～99.1%。     

TRANSACTIONS OF NANJING UNIVERSITY OF AERONAUTICS ＆ ASTRONAUTICS

中采用生物技术手段,对钙果(欧李)进行种苗组织培养技术研究,通过无性系建立、增殖培养、生根培养三个步骤,培育获得了健壮的无性系钙果试管苗。实验表明MS BA1.0 IAA0.2是较好的诱导分化培养基;MS BA0.5 IAA0.2培养基试管苗增殖培养较好;1／2MS IAA0.7培养基诱导生根效果较好。     

矮化蟠桃的育种实践与连锁遗传分析

 利用乔化异质型蟠桃(DwdwSs) 与矮化型圆桃( dwdwss) 或乔化异质型圆桃(Dwdwss) 进行有性杂交, 培育杂种实生苗, 对子代相关性状的分离情况进行了分析。结果显示, 乔化对矮化为一对等位基因, 且乔化对矮化为完全显性, 蟠桃与圆桃为一对等位基因, 蟠桃对圆桃为完全显性。在乔化异质型蟠桃(DwdwSs) 与矮化型圆桃( dwdwss) 的正反交后代中, 没有出现矮化型蟠桃和乔化型圆桃, 乔化蟠桃与矮化圆桃的比例为1∶1; 在乔化异质型蟠桃(DwdwSs) 与乔化异质型圆桃(Dwdwss) 的杂交后代中, 也同样没有出现矮化型蟠桃, 乔化蟠桃、乔化圆桃与矮化圆桃的分离比例为2∶1∶1, 据此得出以下推论, 果实扁平性状与树体乔化性状完全连锁, 树体矮化性状与果实非扁平性状完全连锁, 即矮化突变与扁平果形突变分别发生在不同的同源染色体上, 两者之间没有发生过交换, 不产生dwS配子。     

比久、多效唑、根太阳对金叶假连翘株型的控制效应

为减少金叶假连翘绿篱株型控制的修剪成本,特以6年生金叶假连翘为试材,采用L9(34)正交表设计,研究不同药剂种类、浓度水平、施药频率对其嫩枝长度、嫩枝数目以及叶绿素含量的影响。结果表明,3种药剂的作用效果为B9GTYPP333;随着浓度的增大药效增强;施药频率以2、3次为佳。综合3个指标,以喷施3500mg/LB92次的处理效果最佳。这为用植物生长延缓剂控制金叶假连翘的株型提供了科学依据。     

粉蕉苗期吸芽发育特点及内源激素响应特性

吸芽是香蕉着生于地下茎上的一种营养体,可选留作母株或作种苗,过多的吸芽会与母株进行营养竞争,人工除芽不仅增加了成本,还会增加枯萎病入侵的危险。植物的分枝数量主要受生长素、细胞分裂素和独脚金内酯3种植物激素的协同控制。本文以粉蕉品种“育粉6号”为研究材料,解剖观测苗期吸芽分化情况,测定球茎内生长素、细胞分裂素和独脚金内酯的含量变化,探讨香蕉吸芽分化发育与内源激素的关系。结果表明：粉蕉在10叶龄阶段后开始了吸芽的发育过程,芽眼和伸长芽的增长速率基本保持了恒定,生长素、细胞分裂素和独脚金内酯的含量也呈现出基本保持恒定的现象;独脚金内酯和生长素含量与芽眼的变化量存在显著的负相关,表明独脚金内酯作为生长素的第二信使负调控粉蕉的吸芽发育,起作用的阶段为表面芽点发育为芽眼这一阶段;细胞分裂素与吸芽发育指标之间不存在显著的相关性,表明细胞分裂素在内部芽点-外部芽点-芽眼-伸长芽的这一发育过程中不存在促进作用。研究可为粉蕉在种植过程中使用外源激素调节吸芽的生长发育提供数据基础和理论依据。