李明芳 卢诚 刘兴地 王向社 郑学勤

摘 要 对荔枝无核和焦核机理的研究概况作了综述。指出大孢子发育异常无法完成受精和单性结实是导致荔枝无核的主要原因，今后对无核荔枝无核机理的研究应该着重从大孢子败育和单性结实发生分子机理的角度展开，重点阐明无核荔枝发生大孢子败育、受精被阻和单性结实的分子途径。科技界对荔枝焦核机理的研究主要从组织细胞水平、生理生化角度和分子水平进行：从细胞水平看，主要是胚乳过早解体和胚在胚囊外发育引起合子或胚早期败育，进而导致胚珠败育形成焦核；从生理生化角度看，植物内源激素、多胺、酚类物质以及可溶性蛋白含量都与胚珠败育、焦核形成有关；从分子水平看，两条特异片段OPL-12-1 645 bp与OPL-12-722 bp，可能与荔枝的焦核基因相关。认为今后对荔枝焦核机理的研究应该着重于合子期到心形胚期，从分子水平上阐明究竟是哪些基因异常表达使合子分裂受阻、使胚乳过早解体，使球形胚、心形胚形成受阻。

关键词 荔枝；无核荔枝；单性结实；焦核荔枝

中图分类号 S667.1 文献标识码 A

Abstract This paper reviews the research progress of seedless and stenospermocarpic mechanism in litchi（Litchi chinensis Sonn.）. It points out that the abnormal development of megaspores（or embryo sacs）， the failure of egg fertilization and parthenocarpy are the primary cause contributing to seedless litchi formation， therefore from now on， the study on the seedless mechanism of litchi should focus on the molecular one of the megaspores abortion and parthenocarpy. The most important thing is to clarify their molecular pathway. The stenospermocarpic mechanism of litchi was investigated by scientists from three aspects. At the cellular level， it is endosperms disintegrating ahead of time and embryos growing out of embryo sac that cause zygotes or embryos to abort from the early time of embryonic development， further resulting in abortion of ovules and seeds. From physiological and biochemical angle， the changes of plant endogenous hormones， polyamines， phenolic inhibitors and soluble protein content are closely related to abortion of ovules and formation of stenospermocarpy. At the molecular level， two specific amplified bands OPL-12-1 645 bp and OPL-12-722 bp have been considered as markers of seed-abortion genes in litchi. This paper suggests that in the future the study on the aborted-seeded mechanism of litchi should focus on zygote till heart-shape embryo stages so that it will be elucidated that which genesexpressing abnormally gives rise to zygote division blocked， endosperm disintegrating very early， ball-and heart-shape embryos formation blocked.

Key words Litchi（Litchi chinensis Sonn.）；Seedless litchi；Parthenocarpy；Stenospermocarpic（aborted-seeded）litchi

doi 10.3969/j.issn.1000-2561.2016.05.030

荔枝（Litchi chinensis Sonn.）为无患子科（Sapindaceac）荔枝属（litchi）植物，原产中国南部，至今已有两千多年的栽培史。在这漫长的历史进程中，人们通过实生选种和芽变选种选育出来的荔枝品种和株系多达200个以上。其中，最受老百性青睐的荔枝良种当属无核荔枝和焦核荔枝。所谓无核荔枝是指果实内完全没有核或仅有一个绿豆大小的痕迹，而焦核荔枝指的是果实内的核大小如蚕豆，但是不饱满，呈扁平空瘪状态。……