杉木无性系早-晚龄生长性状的相关性及早期选择的研究

对10年生和7年生的两块杉木无性系试验林历年生长资料进行分析研究，得出结果；从第2年起无性系高，么董长量的F值、方差分量、重复力明显增大，并开始趋于稳定，无性系重复力较高，介于0．65－0．90之间居多。从3－4年生起，各年龄树高、胸径与近期对应性状的相关系数，以及与近期材积的相关系数增大，至趋于稳定。3－4年生后各年龄树高、胸径相关信息量亦表出与相关系数同样的趋势。遗传相关系数大于秩次，表型、环境相关系数，表明年龄间生和匠相关主要受遗传控制，无性系早期选择是有效的。早期选择最佳年龄、随主伐年龄的不同而有所差异，但介于3－4a之间，选择效率D早－V晚高于H早－V晚，前者出现最大选择效率的年龄早于或等于后者，所以选择指标倾向胸径。     

18年生尾巨桉无性系木材纤维形态和基本密度变异研究

对18年生尾巨桉（Eucalyptus urophlla×E．grandis）无性系木材纤维特征与基本密度进行研究,通过测定木材的纤维长度、宽度、壁厚、腔径、木材基本密度,分析结果表明：木材基本密度、纤维长度、纤维长宽比、壁厚、壁腔比在树干径向方向由髓心向外有逐渐增大的规律。纤维长度与基本密度之间呈显著的负相关,纤维宽...     

Quantitative Estimation of Genetic Variability in Morphological Characteristics of Eastern Cottonwood (Populus deltoides Bartr.) Clones

The study was carried out to analyze the genetic variability for different growth parameters in poplar clones at the age of 2 and 3 yr in the nursery. Forty-nine exotic and indigenous clones of poplar were evaluated for eight morphological traits. Clones were planted in randomized block design (RBD) with three replications with four clones in a block in each treatment. Observations for different characters were recorded on six selected competitive clones per genotype. Results showed a high interclonal variability for most parameters. Statistically significant differences among clones indicated that the majority of study characters are controlled by genetic factors, specific to each clone. Highly significant genotypic difference supported by wide range of variation of mean and range values were observed for the characters under study. Significant and positive correlation was observed between diameter at breast height (DBH) and plant height. Leaf lamina length showed positive and significant correlation with petiole length, total leaf length, leaf width, and L/B ratio. Total leaf length showed positive and significant correlation with leaf width and L/B ratio. High estimates of heritability (in a broad sense) were observed for almost all characters in the study. High genetic advance expressed as percent of mean was recorded for petiole length (60.90), followed by plant height (60.78) and collar diameter (44.19) at 2 yr. At the age of 3 yr, genetic advance was found maximum for petiole length (60.05), followed by collar diameter (47.62) and plant height (45.29). The efforts for selecting new clones and their field-testing must continue under a long-term improvement plan so that the best clones can be recommended for plantations and hybridization programs.     

Cloning and sequence analysis of nine novel MYB genes in Taxodiaceae plants

Myeloblastosis(MYB) is one of the largest transcribed factor families in plants. To gain an overall picture of the evolution of MYB genes in relict plants, we cloned nine novel MYB genes in Taxodiaceae plants(Taxodium distichum, Taxodium ascendens, Cryptomeria japonica var. Sinensis, Cryptomeria japonica cv. Araucarioides, Cryptomer Japonica, Metasequoia glyptostroboides, Cunninghamia lanceolata, Taiwania cryptomerioides and Glyptostrobus pensilis). The deduced amino acid sequences for MYBs showed that the nine MYB proteins contained two DNA binding domains. The first domain is from amino acid position 29 to 78, wherein three tryptophanes at 33, 53 and 73 were separated by 19 amino acids, respectively. The second domain is from amino acid position 82 to 127, wherein three tryptophanes at 86, 105 and 124 were separated by 18 amino acids, respectively, whereas the first tryptophane at amino acid position 86 is replaced by a phenylalanine. The characterization of these conserved domains at nine MYBs indicated that they all belong to the R2R3-MYB group. The secondary structure analysis showed that α-helix and β-turn are the major motifs of the predicted secondary structure of MYBs. The three dimensional model of each MYB protein showed that the structure is like clip, making it more flexible and mobile. The similarities between the nine MYB proteins in Taxodiaceae were calculated. The highest identical value of 99% is between CjsMYB, CjMYB and CjaMYB, whereas the lowest value of 82% is between TaMYB and ClMYB. According to the phylogenetic tree, the distances between different genera were relatively large whereas those within genera were relatively small. As expected, accessions of the same genus formed a subgroup before being grouped with other genera.     

杜鹃红山茶CaAPX基因的克隆、表达及功能分析

[目的]利用分子生物学技术探讨杜鹃红山茶CaAPX基因的表达模式及在模式植物烟草中所起的抗寒、耐热作用,为今后山茶花抗逆育种奠定基础。[方法]根据山茶花同源序列设计特异性引物,利用同源克隆和3’,5’-RACE技术,从杜鹃红山茶嫩叶组织中克隆出抗坏血酸过氧化物酶(APX),命名为CaAPX,基因全长1 097 bp,开放阅读框753 bp,编码250个氨基酸。实时荧光定量PCR对杜鹃红山茶7种组织和温度胁迫下该基因的表达模式进行分析。[结果]表明:CaAPX基因在杜鹃红山茶7种组织中均得到表达,但表达水平不一,表达量由高到低依次为:未成熟果实嫩叶花苞叶芽种胚花瓣花芽,其中,未成熟果实中的表达量是其它组织的2.6811.44倍;温度胁迫处理8 h后该基因呈上调表达,CaAPX基因表达量分别是0 h的3.49和2.67倍。CaAPX基因转化烟草分析表明,过量表达CaAPX基因后,APX活性提高了2.58 4.09倍,抗坏血酸(As A)含量提高了2.673.56倍,并且转基因烟草植株的抗寒、耐热能力也获得提高。[结论]通过过量表达CaAPX基因能够提高烟草植株的抗寒、耐热性,为山茶花抗逆育种提供了科学依据。     

科技先行,探索创新,促进海南红毛丹产业发展

简介保亭红毛丹产业发展情况,分析红毛丹产业发展的制约因素,提出促进红毛丹产业发展的思路及今后工作的打算。     

苹果细胞分裂素氧化酶基因MdCKX7.2的克隆及抗性鉴定

采用同源克隆和PCR技术从‘嘎拉’苹果(Malus×domestica Borkh.)中克隆细胞分裂素氧化酶基因MdCKX7.2(基因序列号:MDP0000279125)。该基因含有1 542 bp的完整开放阅读框,编码513个氨基酸。利用Plant CARE数据库对MdCKX7.2启动子顺式作用元件进行预测分析,发现MdCKX7.2启动子序列中存在光、干旱、脱落酸、水杨酸、茉莉酸甲酯等响应元件。基因表达分析发现,‘嘎拉’幼苗中MdCKX7.2的表达明显受干旱和ABA的诱导。通过农杆菌介导的遗传转化获得MdCKX7.2转基因拟南芥植株。抗性试验表明,异位表达MdCKX7.2基因明显提高了拟南芥对干旱胁迫的抗性。拟南芥种子萌发试验表明,在拟南芥中异位表达MdCKX7.2提高了植株对ABA的敏感性,种子萌发率和幼苗鲜质量明显下降,与种子萌发相关基因的表达量明显上调。以上试验结果表明,MdCKX7.2在植物非生物胁迫响应中发挥重要作用。     

野生番茄SpIDD1基因的表达分析及其VIGS载体构建

为鉴定野生番茄的SpIDD1基因并探究其功能,以野生醋栗番茄‘PI365967’为试验材料,利用RT-PCR克隆得到SpIDD1基因的CDS序列,全长1 020 bp,编码339个氨基酸,与普通番茄参考基因组序列相比,SpIDD1只存在一个核苷酸位点的差异。蛋白序列比对和结构分析表明,Sp IDD1含有1个核定位信号和4个保守锌指结构域(C2H2·C2H2·C2HC·C2HC),是一个典型的IDD蛋白。系统进化分析表明,SpIDD1与马铃薯和辣椒的IDD蛋白亲缘关系最近。荧光定量PCR显示,SpIDD1在叶、顶芽和果实中的表达较高,并受干旱胁迫的显著诱导。利用TRV-VIGS系统构建了Sp IDD1的基因沉默载体,并成功侵染番茄。研究结果表明,SpIDD1作为一个典型的IDD基因,很可能参与了番茄的干旱胁迫。本研究为进一步研究该基因的功能及作用机理提供理论依据。     

苹果赤霉素信号转导因子MdGAMYB的克隆和表达分析

以‘长富2号’苹果为试验材料,从其短枝顶芽中克隆得到1个赤霉素信号转导因子MdGAMYB,对其进行生物信息学和表达分析。结果表明,MdGAMYB的开放阅读框(ORF)长度为1 656bp,编码551个氨基酸,蛋白质分子量为59.741 kD。生物信息学分析表明MdGAMYB编码的蛋白存在多个糖基化位点和磷酸化位点;序列分析表明,Md GAYMB和其他物种的GAMYB蛋白有很高的相似性,均含有保守的R2R3 DNA结合域和GAMYB家族所特有的Box1,Box2和Box3保守区域;系统进化分析表明,Md GAYMB与梨、梅花、草莓、枣和葡萄等的GAMYB蛋白具有较高的同源性。实时荧光定量PCR分析表明,Md GAYMB具有组织表达特异性,在叶片、花和芽中的表达量较高。外源GA3处理抑制了花芽孕育和翌年成花,抑制MdGAMYB的表达。在易成花品种‘烟富6号’中的表达量高于难成花品种‘长富2号’。     

苹果‘长富2号’开花调控转录因子基因MdIDD7的克隆及表达分析

以‘长富2号’苹果为试验材料,采用RT-PCR的方法,从其芽中克隆得到INDETERMINATE DOMAIN(IDD)转录因子基因MdIDD7,其开放阅读框长度为1 626 bp,编码541个氨基酸。序列比对和结构域分析表明,该转录因子含有1个核定位信号和4个高度保守的锌指蛋白结构域。系统进化树分析表明,MdIDD7与白梨(Pyrus×bretschneideri,XP_009364602.1)、桃(Prunus persica,XP_007225628.1)和梅(Prunus mume,XP_008220893.1)聚在一起。实时荧光定量PCR表明,MdIDD7在‘长富2号’不同组织(茎、叶、花、果和芽)中均有表达,其中芽的表达量最高。花后40~60 d,MdIDD7在易成花品种‘烟富6号’芽中表达量显著高于难成花品种‘长富2号’。"小年"树顶芽组织中MdIDD7的表达量显著高于"大年"树。在花芽诱导前期,外源GA处理诱导MdIDD7下调表达,而蔗糖处理诱导其上调表达,说明MdIDD7响应激素和糖信号,促进苹果成花。