外源水杨酸对冷藏枇杷果实木质化及相关酶活性的影响

以“解放钟”枇杷为试材,研究了外源水杨酸(SA)对4℃冷藏枇杷果实木质化的影响。试验结果表明：采用1.0 g/L SA浸果20 min处理能抑制枇杷果实苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、肉桂醇脱氢酶(CAD)和过氧化物酶(POD)的活性,从而抑制果实木质素的形成,降低果实硬度,说明SA具有减缓冷藏枇杷果实木质化的作用。     

梨Trihelix转录因子家族成员鉴定及表达分析

Trihelix转录因子可以和光应答相关的GT元件结合,因此又称GT转录因子。本研究从梨基因组中鉴定出16个Trihelix家族基因,依次命名为PbGT1～PbGT16,从同属于蔷薇科的草莓和桃基因组中分别鉴定出11和16个Trihelix家族基因。染色体定位与基因复制事件分析表明,梨、草莓和桃Trihelix家族成员分别分布在12、6和8条染色体上,且梨Trihelix家族存在片段复制事件。种间系统进化树分析表明,梨、草莓和桃Trihelix家族成员分为6个亚族,梨家族成员(PbGT)属于GT-2、Subfamily O和SIP1亚族。结合进化关系及qRT-PCR验证,筛选出PbGT15可能参与调控梨果实石细胞团木质化。     

草莓FaRGA1基因沉默改变开花和匍匐茎抽生特性

RGA是赤霉素信号途径中抑制赤霉素介导反应的核心成分DELLA蛋白的一种，在植物生长发育中扮演重要角色。本研究中预测了栽培草莓FaRGA1的理化特征及二级结构，分析了FaRGA1蛋白保守结构域。系统进化树分析表明FaRGA1蛋白与森林草莓FveRGA1蛋白同源性较高，两者互为直系同源基因。构建了草莓RGA1基因的RNAi载体，以栽培草莓品种‘晶玉’为试材，通过农杆菌介导的遗传转化获得FaRGA1基因被沉默的转基因株系3个。与非转基因对照植株相比，3个FaRGA1沉默株系均表现出连续2年不开花且持续抽生匍匐茎的特性，且短缩茎明显伸长并发生木质化。本研究中发现FaRGA1基因在栽培草莓中对匍匐茎形成具有抑制作用并促进开花，这为今后基于FaRGA1的草莓分子育种奠定了基础。     

Expression of ROP/RAC GTPase genes in postharvest loquat fruit in association with senescence and cold regulated lignification

ROP/RAC GTPases regulate various development processes and play important roles in plant defense responses. Recently, lignification or secondary cell wall formation related ROP members were reported in rice, zinnia, cotton and Eucalyptus. The present study aimed to investigate the possible association of loquat ROPs with flesh lignification under different temperatures. Four ROP cDNA fragments, EjROP1.1, EjROP1.2, EjROP2 and EjROP3, were isolated from ‘Luoyangqing’ (LYQ) loquat fruit, and all of them shared over 80% nucleotide identity with known ROPs from other plants. Sequence analysis revealed that EjROP1.1, EjROP2 and EjROP3 might be functional while EjROP1.2, with mutated C-terminal resulted from a 65 bp deletion in the corresponding nucleotide sequence as compared with EjROP1.1, might be dominant-negative and consequently act as a negative regulator of ROP signal transduction. Increase in expression of EjROP1.1, EjROP2 and EjROP3 was observed during first 4 or 6 d of storage at 20 °C and was positively correlated with the increase in flesh firmness. Expression of EjROP1.2 was constantly low under 20 °C but was quickly, within 6 h, induced under 0 °C, and it increased by about 20 times within 24 h. The expression was induced under 5 °C as well but not so strong as that under 0 °C, and transfer of fruit from 5 °C to 0 °C re-stimulated the expression. The possible roles of EjROPs played during senescence and cold regulated lignification was discussed, and the simultaneous increase in the expression of three functional EjROPs and the negative regulator EjROP1.2 was suggested to be important for maintaining a ROP rheostat to protect cells from excessive lignification. To our knowledge, this is the first study on a dominant-negative ROP resulted from a deletion mutation, and a ROP responded to low temperature.     

冷害对采后“大五星”枇杷果实贮藏品质及木质化败坏的影响

研究冷害对采后"大五星"枇杷果实贮藏品质及木质化的影响,旨在阐明冷害温度下枇杷果实品质劣变,特别是木质化败坏的规律,为枇杷贮藏保鲜提供理论依据。"大五星"枇杷采后分别于冷害温度[(3±1)℃,简称3℃]和非冷害温度[(8±1)℃,简称8℃]贮藏30d,定期测定贮藏期间两组的品质及相关指标变化。结果表明,3℃条件下枇杷果实在第10天开始出现冷害症状,随后日趋严重,而在8℃条件下的果实30d内发生冷害程度很轻。冷害会加速枇杷采后失重率、膜透性、木质素、PAL、POD活性的上升,促进TSS、TA和VC含量下降。     

相关酶对花生果针木质化的影响

测定了6个花生品种果针生长发育过程中不同部位的多胺氧化酶（PAO）、过氧化物酶（POD）活性,研究了PAO、POD对花生果针人土的影响．结果表明,不同部位的PAO、POD活性不同,总的来说果针尖端活性最高,果针中部次之,果针上部最低．不同品种酶活性不同,果针生长天数对酶活性影响不大．     

穗条木质化程度和储存时间对思茅松容器苗嫁接成活率的影响

研究了思茅松穗条的木质化程度和储存时间对嫁接成活率的影响,结果表明:老枝比嫩枝的嫁接成活率更高;嫁接成活率随着穗条储存时间的增加而降低,当穗条置于冷库(0~10℃)条件下,穗条储存7天后嫁接成活率为10%,常温条件下,穗条储存5天后嫁接成活率仅有3.3%。     

谷光甘肽对冷藏枇杷果实木质化相关生理指标的影响*

  以“解放钟”枇杷(Eriobotrya japonica LindlcvJiefangzhong)为试材, 研究外源还原型谷胱甘肽(glutathione, GSH)对6 ℃冷藏枇杷果实苯丙氨酸解氨酶(phenylalanine ammonia lyase, PAL)、多酚氧化酶(polyphenol oxidase , PPO)、4-香豆酸辅酶A连接酶(4 coumarate coenzyme A ligase, 4 CL)、肉桂醇脱氢酶(cinnamyl alcohol dehydrogenase, CAD)、过氧化物酶(peroxidase, POD)和多胺氧化酶(polyamine oxidase, PAO)活性以及可溶性糖含量变化与果实木质化的关系。结果表明, 外源GSH处理通过抑制冷藏枇杷果实中PAL,POD和PAO活性上升, 从而抑制果实木质素的形成,并延缓可溶性糖的下降; 但GSH处理对果实PPO,CAD和4 CL酶活力影响较小, 它们可能在枇杷果实木质化中不起主要作用。GSH具有减缓冷藏枇杷果实木质化的作用, 其中以10g/L和15g/L的GSH所处理的枇杷果实木质化程度较低。关键词：枇杷; 木质化; 谷胱甘肽(GSH); 苯丙氨酸解氨酶(PAL); 过氧化物酶(POD); 多胺氧化酶(PAO)100, China     

谷光甘肽对冷藏枇杷果实木质化相关生理指标的影响

以"解放钟"枇杷(Eriobotrya japonicaLindl.cv.Jiefangzhong)为试材,研究外源还原型谷胱甘肽(glu-tathione,GSH)对6℃冷藏枇杷果实苯丙氨酸解氨酶(phenylalanine ammonia-lyase,PAL)、多酚氧化酶(poly-phenol oxidase,PPO)、4-香豆酸辅酶A连接酶(4-coumarate coenzyme A ligase,4-CL)、肉桂醇脱氢酶(cin-namyl alcohol dehydrogenase,CAD)、过氧化物酶(peroxidase,POD)和多胺氧化酶(polyamine oxidase,PAO)活性以及可溶性糖含量变化与果实木质化的关系。结果表明,外源GSH处理通过抑制冷藏枇杷果实中PAL,POD和PAO活性上升,从而抑制果实木质素的形成,并延缓可溶性糖的下降;但GSH处理对果实PPO,CAD和4-CL酶活力影响较小,它们可能在枇杷果实木质化中不起主要作用。GSH具有减缓冷藏枇杷果实木质化的作用,其中以1.0 g/L和1.5 g/L的GSH所处理的枇杷果实木质化程度较低。