喷施吲哚-3-乙酸 (IAA) 对番茄及其上B型烟粉虱的影响

【目的】不同植物生长调节物质对植食性昆虫产卵、发育、取食等常有促进或抑制作用,进而影响植物与昆虫的互作关系。本研究旨在阐明常用的植物生长调节剂吲哚-3-乙酸对B型烟粉虱Bemisia tabaci (Gennadius)的影响,进而探索防治烟粉虱环境友好的方法,同时期望获得更加优质的烟粉虱用作替代寄主饲养寄生蜂。【方法】对番茄 Solanum lycopersicum L.植株外源喷施吲哚-3-乙酸(IAA),检测其生理生化的响应;记录B型烟粉虱存活率、产卵量并测量解毒酶等指标。【结果】喷施IAA后番茄叶片含水量略有上升,叶面积增大,叶绿素含量增加,过氧化物酶(POD)活性降低,多酚氧化酶(PPO)活性升高,超氧化物歧化酶(SOD)活性变化不显著(P＞0.05)。喷施IAA后番茄上B型烟粉虱成虫存活率高于对照组,其中50 mg/L IAA番茄上B型烟粉虱成虫存活率和总产卵量最高,250 mg/L IAA存活率最低;喷施IAA 120 h后烟粉虱总产卵量升高;碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)活性较对照升高。【结论】喷施不同浓度的IAA溶液后,番茄植株的生理生化水平发生不同程度的改变,烟粉虱成虫的存活状况、产卵量以及体内解毒活性也会产生不同程度的改变。适宜剂量的IAA处理能够使烟粉虱的生存表现更加优异,从而为饲养寄生蜂提供优质的替代寄主。     

营养胁迫诱导的油菜子叶衰老过程中IAA氧化酶和细胞分裂素氧化酶活性的变化

以离体油菜子叶为材料,研究了营养胁迫诱导的子叶衰老过程中吲哚乙酸氧化酶(IAA氧化酶)和细胞分裂素氧化酶活性的变化。在光照条件下,离体子叶在不含任何无机元素的0．8％的琼脂中培养9d后,出现明显的衰老迹象(叶绿素含量下降,丙二醛含量上升),15d时完全死亡。在营养胁迫诱导的衰老过程中,IAA氧化酶和细胞分裂素氧化酶的活性表现出相似的变化趋势,在诱导处理1d时,两种酶的活性均比处理前有明显下降,之后又随着衰老进程逐渐上升。IAA氧化酶活性在诱导处理11d时达到高峰,超出处理前30％以上;比对照高出1倍以上;而细胞分裂素氧化酶活性在诱导处理13d时达到高峰,比对照高出3倍以上,也超过了处理前的水平。衰老过程中IAA氢化酶和细朐分裂素氧化酶活性的上升可能是导致内源激素含量下降的重要原因。     

GA3和IAA对慈竹综纤维和叶绿素含量动态积累的调控效应

以慈竹为材料,研究不同浓度和配比的GA₃和IAA对综纤维和叶绿素含量动态积累的调控效应,为纸浆用竹的遗传改良研究提供理论依据。研究结果表明, GA₃和IAA处理对慈竹综纤维动态积累调控作用具有差异。处理前30 d内,GA₃50IAA200处理慈竹综纤维积累强度高于GA₃200IAA50处理,40~50 d时,则反之。GA₃和IAA处理的综纤维最终水平明显高于空白对照,差异达极显著水平。GA₃和IAA处理能提高慈竹叶绿素含量,GA₃200IAA50处理慈竹叶绿素含量高于GA₃50IAA200处理。相关分析结果表明,叶绿素含量与综纤维含量间呈不显著正相关关系。     

Roles of leaf in regulation of root and shoot growth from single node softwood cuttings of grape (Vitis vinifera)

The role of leaf in regulation of root and shoot growths in single node softwood cuttings of grape (Vitis vinifera) was characterised. Leafy cuttings showed early rooting, vigorous root growth and subsequent shoot development. Defoliation at planting induced early sprouting, but adversely affected rooting and decreased the survival of cuttings irrespective of pre‐planting treatment with 100 μM indole 3‐acetic acid (IAA). Treatment with IAA did not affect the percent rooting of leafy cuttings but increased root and shoot growth. Leaf weight (wt) and leaf area of the cuttings showed a highly significant correlation to root wt of the new plant at 4 wk after planting, while cutting stem + petiole wt was either not or less significantly correlated to root and shoot weights of the subsequent plant. The greater the area or wt of leaf, the better the root and shoot growths, implying that leaf contributed to adventitious root growth. However, retaining the leaf for just 2 days was enough to stimulate rooting in more than 80% of the cuttings, suggesting that leaf tissue could also induce root formation. Root growth increased with the period of leaf retention but leaf removal before 3 wk triggered sprouting leading to high mortality in rooted cuttings. Bringing the leaf closer to the rooting zone by preparing leaf at base (LAB) cuttings delayed rooting and sprouting compared with the standard leaf at top (LAT) cuttings. An inhibitory effect on rooting and sprouting by the exposed upper internode region in LAB cuttings is suggested.     

Turnover of cell wall components during internode growth in <Emphasis Type="Italic">Merremia emarginata</Emphasis>

The internodes of Merremia emarginata plant showed exceptionally high stretchability throughout the development period. Therefore, it provides excellent material to study the changes undergoing during cell elongation. In this study, the influence of the hormone treatments (GA₃, PAA and NAA) on the wall component synthesis was analyzed in relation to elongation growth during internode development. A clear increasing trend of wall components was observed with increase in internode length. The non-esterified pectic substances were markedly correlated with internode length while esterified pectic substances showed correlation only in hormone treated internodes. Low molecular weight xyloglucans content showed correlation only in GA₃ and NAA treated internodes, while high molecular weight xyloglucans were significantly correlated with length of internodes treated with PAA and NAA.     

生长素信号转导研究进展

长素的信号转导是一个复杂的网络系统,在信号的感知上,除了存在ABPI介导的膜上感知途径外,还有其他的感知途径。G蛋白参与诱导生长素信号的胞内传递,生长素信号转导的第二信使包括离子型第二信使、磷酯酶A2、脂活化蛋白激酶、MAPK和PINOIND等。AUX／IAA蛋白的泛素化降解在生长素反应中发挥关键性作用,ARF和AUX／IAA蛋白相互作用调节生长素响应基因的转录。     

玉米素和IAA对番茄子叶再生的影响

高水平的外源ZT抑制番茄子叶不定芽形成,导致畸形芽大量出现,延缓再生芽的生根过程。在低水平的ZT和高浓度的IAA共同作用下,不定芽的再生速度加快,正常芽比例增加,后期生根过程明显加快。     

杜仲形成层休眠机理

对杜仲 (EucommiaulmoidesOliv .)一年生枝条休眠中的芽和维管形成层的结构和蛋白质含量进行了研究 ,探讨了杜仲不同休眠期转化的生理生化机理。结果证实了杜仲树的休眠期包括 2个被动休眠期和一个生理休眠期。在生理休眠期 ,无论用外源IAA处理 ,还是给予适当的温度和光照 ,形成层都不能恢复活动。而且 ,雌株进入各个休眠阶段的时间都比雄株早。树皮中的蛋白质含量在第一被动休眠期间 (Q1)显著地逐步增高 (P <0 .0 1) ,进入生理休眠期 (R)后 ,急剧降低 ,但第二被动休眠期 (Q2 )开始后又显著升高 (P <0 .0 1)。杜仲雌雄株树皮中的蛋白质含量变化趋势基本一致 ,但雄株发生变化的时间比雌株早。SDS_PAGE电泳结果表明 ,在Q1 R Q2的转变期出现一11.8kD的特异蛋白条带。此特异蛋白条带可能与形成层休眠期中各阶段的转变调节有关。