荔枝雄花性别决定过程中细胞超微结构的变化

荔枝雄花雌蕊原基在大孢子母细胞减数分裂后开始衰退.内质网历经增生扩展,穿壁相连,同心缠绕,多条平行弯曲,不规则堆叠.内质网和高尔基体产生许多囊泡,囊泡在细胞内含物的降解和运输过程中起着重要的作用.线粒体在雌蕊原基细胞衰败的前、中期数量增加,后期分批降解.过氧化物酶体在雌蕊原基细胞衰败的中期紧挨核短暂出现.细胞核的染色质凝集断裂;核周腔扩大,形成胀泡;染色质趋边,外泄.细胞原生质表现出有序的、在膜包裹下的降解,首先是核糖体,而后依次是:过氧化物酶体、内质网、高尔基体、线粒体、核.雌蕊原基的衰败历程可能是一种程序性细胞死亡的过程.     

桂西南早熟荔枝实生资源遗传多样性的ISSR分析

利用ISSR标记技术对83份早熟荔枝(品种)单株遗传多样性进行分析。筛选出多态性高的10条IS-SR引物,共扩增出128条DNA条带,其中多态性带107条,多态性百分率为83.59%,表明桂西南早熟荔枝实生资源遗传多样性较丰富;用NTSYS软件计算出这83份材料的DICE相似系数在0.64～0.95之间,遗传亲缘关系较近;用UPGMA方法构建分子树状图,在相似系数0.75时,可将栽培品种与桂西南早熟实生单株区分开。各地区资源混杂聚类在一起,不能按地区单独聚类。     

荔枝若干重要果实品质性状的QTL分析

以‘马贵荔＇ב焦核三月红＇76株F_1代群体为试材,检测了酒石酸、苹果酸、蔗糖含量和单果重4个果实性状分离的情况。结果表明,4个性状表现为连续分布,具有数量性状的典型特征,与4个果实性状连锁的QTL位点23个,其中控制酒石酸的QTL为2个,控制苹果酸的QTL为4个,控制蔗糖的QTL为12个和控制单果重的QTL为5个。各QTL的LOD值在3.15～5.61之间,可解释13.85%～88.3%的表型变异。     

荔枝皮黄酮抑菌性能及其作用机理研究

采用荧光分析法测定荔枝皮中总黄酮含量,并研究了荔枝皮黄酮对常见4种微生物的抑菌活性及机理。结果表明,其黄酮纯度与得率分别为48%和13.61%;同时,采用牛津杯法测得荔枝皮黄酮对金黄色葡萄球菌、大肠杆菌和酵母菌的抑菌圈直径分别为15.1、14.0和13.8 mm;采用菌饼法测得对黑曲霉的抑菌率为28.75%。采用平板稀释法测得金黄色葡萄球菌和大肠杆菌的最低抑菌浓度MIC为2.5 mg/mL,最低杀菌浓度MBC为5mg/mL,而酵母菌和黑曲霉的MIC为5 mg/mL,没有杀菌能力。扫描电镜实验结果表明,荔枝黄酮的抑菌性和杀菌功能与其对金黄色葡萄球菌细胞和细胞壁结构的破坏直接相关。     

Induction,purification, and characterization of a thermo and pH stable laccase from Abortiporus biennis J2 and its application on the clarification of litchi juice

A fungus J2 producing laccase with high yield was screened in soils and identified as Abortiporus biennis. The production of laccase was induced by 0.1 mM Cu²⁺, 0.1 mM tannic acid, and 0.5 M ethanol. The laccase from Abortiporus biennis J2 was purified to electrophoretic homogeneity by a couple of steps. The N-terminal amino acid sequence of the enzyme was AIGPTADLNISNADI. The properties of the purified laccase were investigated. The result showed the laccase from Abortiporus biennis J2 is a thermo and pH stable enzyme. The laccase activity was inhibited by Hg²⁺, Cd²⁺, Fe²⁺, Ag⁺, Cu²⁺, and Zn²⁺, while promoted by Mg²⁺, Mn²⁺ at 10 mM level. Purified laccase was used to the clarification of litchi juice. After treatment with this laccase, the phenolic content of litchi juice had been found to be greatly reduced along with an increase in the clarity of the juice. The result indicated the potential of this laccase for application in juice procession.     

炭疽病菌侵染对荔枝果实生理生化变化的影响

本研究测定了荔枝果实人工接种炭疽病菌后呼吸速率、乙烯释放量的变化和果皮氧化、过氧化作用以及与酚类代谢有关的几种酶活性的变化。结果表明,接种炭疽病菌的荔枝果实呼吸速率和乙烯释放量显著增高,果皮活性氧(O₂^·)产生速率和丙二醛(MDA)含量显著增加,超氧化物歧化酶(SOD)活性显著降低,过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性显著增高。说明炭疽病菌的侵染可导致荔枝果实呼吸速率和乙烯释放量的增高,加速荔枝果皮氧化和过氧化进程,并诱导荔枝果皮PPO、POD、PAL活性增高,是加速采收后荔枝果实衰老、褐变、腐烂的一个重要原因。     

冬季土壤含水量对糯米糍荔枝花芽分化的影响

冬季适度干旱有利于糯米糍荔枝的花芽分化,对砂壤土而言,土壤含水量的最适范围为12%~15%,低于10%或高于16%都不利于花芽分化。     

一种适于提取荔枝花与幼果组织总RNA的方法

介绍了一种从荔枝花与幼果组织中提取高质量和较高产量的总RNA的方法,该方法提取的总RNA可以满足构建cDNA文库、开展RT-PCR、Northern杂交分析、基因表达差示分析等方面研究的要求。     

ATP-induced Changes in Energy Status and Membrane Integrity of Harvested Litchi Fruit and its Relation to Pathogen Resistance

Litchi is a subtropical fruit of high commercial value on the international market but the fruit deteriorates rapidly after harvest due to rot development caused by Peronophythora litchii. To investigate the role of energy metabolism during disease development on harvested litchi fruit, fruits were dipped into solutions of either 0 or 1.0 mm adenosine triphosphate (ATP) for 3 min before being inoculated with Peronophythora litchii or not. Fruit were then stored for 6 days at 25°C and 90–100% relative humidity. Significant reductions in pericarp browning and disease severity and significant delays in membrane permeability and malondialdehyde (MDA) content were found in ATP‐treated and P. litchii‐inoculated fruit. Higher ATP concentrations and adenylate energy charge (EC) were observed in ATP‐treated fruit. In addition, lower activities of phospholipase D, acid phosphatase and lipoxygenase enzymes involved in membrane lipid peroxidation and hydrolysis were recorded in ATP‐treated fruit. Thus, treatment with ATP maintained higher energy levels, inhibited activities of the membrane hydrolysis‐related enzymes, reduced membrane lipid peroxidation and helped maintain membrane integrity of the harvested litchi fruit at the early stage of storage, which could account for the inhibition of disease development of P. litchii‐inoculated fruit.     

荔枝果皮多酚氧化酶酶促褐变的研究

从荔枝果皮分别提取多酚氧化酶及其天然底物,两者相作用,形成褐色产物,酶促褐变是荔枝果皮变褐的原因。 从荔枝果皮提取的酚类物质中分离出多酚氧化酶的天然底物。此底物的紫外吸收光谱分别在215和280 nm有一强的和一弱的吸收峰,它的红外吸收光谱在3190、1600、1500 cm~(-1)有很强的吸收峰。