Rudimentary leaf abortion with the development of panicle in litchi: Changes in ultrastructure, antioxidant enzymes and phytohormones
Rudimentary leaf abortion with the development of panicle in litchi: Changes in ultrastructure, antioxidant enzymes and phytohormones
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DOI：
10.1016/j.scienta.2008.04.004
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发表时间：
2008-07
影响因子：
4.3
通讯作者：
Biyan Zhou;Houbin Chen;Xuming Huang;Ning Li;Zhiqun Hu;Zhi-can Gao;Yong Lu
中科院分区：
文献类型：
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作者：
Biyan Zhou;Houbin Chen;Xuming Huang;Ning Li;Zhiqun Hu;Zhi-can Gao;Yong Lu
荔枝（Litchi chinensis Sonn.）是由叶原基、残叶和穗原基组成的混合芽。根据田间观察，幼叶的命运取决于穗原基的环境和发育。幼穗发育旺盛导致残叶败育。本研究以三种类型的残叶为材料，即上部叶（UL）、下部叶（AL）和非下部叶（NAL），其中上部叶包着正在发育的穗原基，在穗发育一段时间后必定会伸长，下部叶（AL）有腋穗出现，在轻微的外力作用下会伸长，下部叶（NAL）包着营养芽，正常发育。从CVS的顶芽中取样。糯米醋和妃子笑。对‘糯米刺’三种类型残叶叶柄基部的超微结构进行了观察。细胞自溶的迹象，例如，在UL中，局部细胞出现液泡膜破裂，液泡与细胞质融合，而AL中则出现大量细胞死亡，表明两种类型的残叶处于不同的败育阶段。UL处于流产的早期阶段，而AL处于流产的晚期阶段。在NAL的非血管组织中未观察到细胞自溶。在‘糯米蜜’中，AL的超氧化物歧化酶（SOD）活性显著低于UL和NAL，而后两者的酶活性差异不显著。妃子笑的3种残叶间SOD活性差异不显著，但AL的SOD活性最低。两个品种AL的过氧化物酶（POD）活性均显著高于NAL。‘糯米刺’的UL的POD活性低于NAL，而‘妃子笑’的POD活性高于NAL。抗坏血酸过氧化物酶（APX）活性以NAL最高，UL和AL之间差异不显著，H2 O2浓度以AL最高。NAL的玉米素+玉米素核苷（ZRs）、生长素（IAA）和赤霉素（GA 4 +7）含量高于AL，脱落酸（阿坝）含量低于AL，NAL的IAA、GA 4 + 7和ZRs总量（TC）及（IAA+ GA 4 +7+ZRs）/阿坝比值（RTC）均高于UL和AL。结果表明，幼穗发育引起的残叶败育可能与细胞程序性死亡、抗氧化活性降低和H_2O_2增加有关，并与成熟叶的衰老和脱落有相似的激素调控作用（ZR、IAA和GA_（4 + 7）减少和阿坝增加）。
Floral bud of litchi (Litchi chinensis Sonn.) is a mixed bud that consists of leaf primordia, rudimentary leaves and panicle primordia. According to field observation, the fate of rudimentary leaves depends upon the environment and development of the panicle primordia. Vigorous development of panicle results in abortion of rudimentary leaves. In this study, three types of rudimentary leaves, the upper leaves (UL) which subtended a developing panicle primordium and were bound to abscise after a period of panicle development, the abscising lower leaves (AL) which had an emerging axillary panicle and would abscise under a light external force, and the non-abscising lower leaves (NAL) which subtended a vegetative bud and would develop normally, were sampled from the terminal shoots of cvs. ‘Nuomici’ and ‘Feizixiao’. Ultra-structure of the petiole base in the three types of rudimentary leaves in ‘Nuomici’ was observed. Signs of cell autolysis, e.g., tonoplast disruption and fusion of vacuole and cytoplasm, were found in localized cells in UL, while massive cell death was observed in AL, suggesting that the two types of rudimentary leaves were at different stages of abortion. The UL was at an early stage of abortion, whereas AL at a late stage of abortion. Cell autolysis was not observed in the nonvascular tissues in NAL. In ‘Nuomici’, AL had a significantly lower superoxide dismutase (SOD) activity compared to the UL and the NAL, while the latter two had no significant difference in the enzyme activity. In ‘Feizixiao’, however, no significant difference was found among the three types of rudimentary leaves, although AL had the lowest SOD activity. Peroxidase (POD) activity in AL in both cultivars was significantly higher than that in NAL. The UL had a lower POD activity in ‘Nuomici’, but a higher activity in ‘Feizixiao’ compared to NAL. Ascorbate peroxidase (APX) activity was the highest in NAL, and there was no significant difference between the UL and AL. H2O2concentration was the highest in AL in the two cultivars. The NAL had higher levels of zeatin plus zeatin riboside (ZRs), auxin (IAA) and gibberellin (GA4+7), and lower levels of abscisic acid (ABA) than AL. Total concentration of IAA, GA4+7and ZRs (TC) and the ratio of (IAA+GA4+7+ZRs)/ABA (RTC) in NAL were higher than those in UL and AL in the two cultivars. The RTC in UL was higher than that in AL. The results suggested that abortion of the rudimentary leaves caused by panicle development may involve programmed cell death, reduced antioxidant activity and increased H2O2and share similar hormonal control (reduced ZRs, IAA and GA4+7and increased ABA) to the senescence and abscission of mature leaves.