喷施GA3和乙烯利对柿果实成熟及内源GAS活性,ABA含量的影响

选用柿极晚熟品种宫崎无核,于果实发育第二期末(10月19日),叶面喷施100ppm的GA_3明显地抑制了果实的肥大生长、着色、糖的积累及果肉软化。对果实内源GAs活性和ABA含量进行分析的结果表明,叶面喷施GA_3使内源GAs活性大大提高,同时使ABA的增加受到抑制。与GA_3处理相反,果实发育第三期(10月1日),对中熟品种富有进行25ppm乙烯利的叶面喷施处理,明显地促进了果实的成熟,其作用尤以促进着色、加速果实软化最为明显。对内源GAs活性及ABA含量亦有明显影响,前者因乙烯利处理而降低,后者则因乙烯利处理而增大。     

小麦粒重形成过程中内源ABA和GAs的变化及其调节

本文探讨了生长调节剂 MET 和 BR 对小麦穗器官发育、穗粒数和粒重形成的影响。分析了小麦穗粒重形成过程、过氧化物酶活性、内源 ABA 和 GAs 含量及功能叶片光合强度在处理问的差别。结果表明:药隔期叶面喷洒 BR 对穗基部和顶部弱势小穗、外围弱势籽粒有促进作用。MET 却对强势籽粒的干物质积累有抑制作用。经 MET,BR 处理后,旗叶光合强度均有不同程度的增加,效果随处理后时间的延续而逐渐降低。在粒重形成过程中,内源 ABA、GAs 含量和过氧化物酶活性的变化均与籽粒建成、灌浆、成熟进程各发育期相对应。     

赤霉酸对杂交水稻种子淀粉酶同工酶形成的调节机理研究初报

 以杂交水稻汕优6号和对照品种广陆矮4号为材料，通过GA3和放线菌D处理研究了水稻种子淀粉酶同工酶的特征。结果表明，杂交水稻种子中出现的淀粉酶同工酶对GA3反应不同，其中α-淀粉酶（A带）和β-淀粉酶（B带）都不受GA3的影响，而另一条α-淀粉酶（C带）则依赖于GA3的诱导。表明不同的α-淀粉酶同工酶的合成有着不同的调节机理。另外，RNA合成的专一抑制剂对α-淀粉酶同工酶的形成无影响。推测水稻种子可能预存有相应的mRNA，在萌发时通过GA3的激活而诱导α-淀粉酶的生物合成。     

赤霉素及其功能类似物与赤霉素受体的研究进展

赤霉素是一类以贝壳杉烯为骨架的植物激素,现已鉴定出136种赤霉素结构,但仅有少部分具有调节植物生长和发育的生理功能。近年来,赤霉素受体的研究取得了重大突破,尤其是最近成功鉴定了拟南芥Arabidopsis thaliana中GA3/GA4-GID1A-DELLA复合物的晶体结构,这为基于受体蛋白结构进行新型赤霉素功能类似物的生物合理设计奠定了重要基础。主要针对赤霉素及其功能类似物的化学结构与合成、赤霉素受体蛋白的结构特征及其与赤霉素类化合物分子间的相互识别规律进行归纳和总结,以期能够为以生物靶标蛋白为导向,开发新型骨架的赤霉素功能类似物提供参考。     

Effects of the molluscicidal agent GA-C13:0, a natural occurring ginkgolic acid, on snail mitochondria

Ginkgolic acids (GAs) from the leaves and sarcotesta of Ginkgo biloba L. represent a new kind of molluscicide agent. To date, the mechanism(s) for the observed molluscicidal activity remains largely unknown. Since GA-C_13:0 has effectively inhibited snail mobility, we examined the effects of the compound on mitochondrial function and gene expression as compared to niclosamide. Snail mitochondrial damage induced by GAs was tested using transmission electron microscopy (TEM) and gene-expression profiling of five mitochondrial enzymes using real-time PCR. GA-C_13:0 was found to have a pronounced effect on snail mitochondria with gross ultrastructural changes. In addition, GA-C_13:0 was also found to inhibit the gene expression of four mitochondrial enzymes including cytochrome c oxidase, adenosine triphosphate (ATP) synthase, cytochrome b and dihydronicotinamide adenine dinucleotide (NADH) dehydrogenase. In contrast, niclosamide did not show such effects on mitochondrial function and gene expression, suggesting that the molluscicidal activity of GA-C_13:0 and niclosamide differed. Our results imply that snail mitochondria are a potential target for the molluscicidal activity of ginkgolic acids.     

转KN1毛果杨细胞分裂素、赤霉素含量及其相关形态结构

为了研究KN1基因超量表达对木本植物生长发育的影响,本研究测定了转KN1基因毛果杨细胞分裂素类激素及赤霉素的含量,并进行表型及解剖结构观察。结果表明,转基因毛果杨植株细胞分裂素类激素ZR、dhZR和iPA的含量分别为14.14ng/g、18.29ng/g和12.43ng/g,明显高于对照的9.44ng/g、12.47ng/g和7.60ng/g,而赤霉素GAs含量为9.61ng/g,低于对照的12.14ng/g,从而引起其植株矮化、分枝增加、叶片增厚、叶色变深、表皮细胞增大、栅栏和海绵组织发达等现象。本研究将为探索KN1基因对木本植物生长发育的影响提供依据。     

乙炔催花对凤梨‘丹尼斯’花芽分化及内源激素含量的影响

为了探讨凤梨开花的生理机制以及为凤梨花期调控提供理论依据,以凤梨‘丹尼斯’为试材,研究乙炔催花对其花芽分化及内源激素含量的影响。结果表明：乙炔催花7天后诱导‘丹尼斯’进入花芽分化状态,其花芽分化进程可分为花芽未分化期、花序原基分化期、花原基分化期、花萼花瓣分化期、雌雄蕊分化期。在整个花芽分化过程中,植株生长点及叶片中生长素（IAA）、脱落酸（ABA）含量未见明显改变,而玉米素核苷（ZRs）在花序原基分化期和花原基分化期呈现出2次显著增加,赤霉素（GAs）含量在花序原基分化期和器官分化早期显著下降,从而引起ABA/GAs、ZRs/GAs、ZRs/IAA比值在花序原基分化期、花原基分化期和器官分化早期显著增加。表明,高水平的ZRs含量、ABA/GAs、ZRs/GAs、ZRs/IAA比值以及低水平的GAs含量有利于凤梨‘丹尼斯’花芽分化的完成。     

Pre-maturity α-amylase in wheat: The role of abscisic acid and gibberellins

The occurrence of pre-maturity α-amylase (PMA) is a major cause of poor bread-making quality (low Hagberg Falling Number) in wheat grain. In susceptible genotypes, it involves the excessive accumulation of high isoelectric point (pI) α-amylase in mature grain prior to germination and in the absence of pre-harvest sprouting. Several factors regulate PMA formation in developing grain, including genotype, agronomy, and environmental conditions. In particular, a cold period during mid-grain development has been found to be a major stimulus for PMA induction. Although the factors affecting the PMA occurrence are well known, little is known about the molecular mechanism governing its induction. The plant hormones abscisic acid (ABA) and gibberellins (GAs) influence various aspects of grain development, and it has been suggested that PMA involves changes in the amount of these hormones or the sensitivity of the grain to these hormones. This review summarizes recent studies investigating the role of ABA and GAs in PMA induction and PMA occurrence.     

生物种衣剂与赤霉素互作对玉米种子发芽及幼苗生长的影响

实验结果显示，ZSB生物种衣剂与GA对潞玉13玉米种子发芽及幼苗生长有显著的促进作用。GA、ZSB、ZSB＋GA3种包衣处理对玉米种子的发芽势有一定抑制作用，但能使种子的发芽率、活力指数明显增加。与对照相比，种子经处理后，不仅其幼苗的苗高、根长、苗鲜重、根鲜重和根数均显著提高，且幼苗叶片中的叶绿素含量也明显增加。3个处理中，ZSB＋GA表现最好。