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systematically investigated using the ‘ Feizixiao’ ECs as materials subcultured on the medium supplemented with
exogenous putrescine (Put)ꎬ spermidine (Spd)ꎬ and spermine (Spm). The results were as follows: (1) Exogenous
Putꎬ Spd and Spm treatments significantly increased the EC proliferation rate and reduced the amount of induced somatic
embryos and number of germinations. The proliferated EC cells after exogenous PA treatments were more consistent in
size and stained deeply and evenly. Furthermoreꎬ multicellular proembryos in EC were reducedꎬ and fully differentiated
early cotyledon embryos could be seen. (2) All the exogenous PA treatments significantly increased the endogenous PA
content in EC. Among themꎬ Put treatment had the highest content of each endogenous PA component and total
PA. When the EC proliferated on the medium containing exogenous PAs was transferred to the medium without exogenous
PAs (recovery culture) for proliferatingꎬ the Put content in the EC was still significantly higher than the controlꎬ
howeverꎬ the endogenous Spd and Spm were significantly decreased. (3) Exogenous Put treatment significantly increased
the activities of ornithine decarboxylase (ODC)ꎬ arginine decarboxylase (ADC)ꎬ and diamine oxidase (DAO) in ECꎬ
while exogenous Spd and Spm treatments significantly reduced the activities of ODC and ADC in ECꎬ and exogenous Spd
significantly increased the polyamine oxidase (PAO) activity. When transferred to the recovery culture mediumꎬ the
ADC and DAO activities of newly proliferated EC were significantly lower than those of EC cultured with exogenous PAsꎬ
but there was no significant difference in ODC and PAO activities. In summaryꎬ the exogenous PAs can affect
endogenous PAs content by regulating the activities of enzymes related to PAs metabolismꎬ thereby affecting EC
proliferation and somatic embryo induction in litchi. These results provide a basis for further study on the mechanism of
PAs regulating embryogenesisꎬ and improve litchi regeneration efficiency in vitro.
Key words: litchi (Litchi chinensis)ꎬ plant regenerationꎬ histological sectionꎬ polyaminesꎬ metabolic enzymes
荔枝(Litchi chinensis) 是我国华南重要的南亚 在于原核生物及真核生物中ꎬ具有强烈生物活性
热带果树ꎬ是助推乡村振兴重要产业之一(陈厚彬 的低分子量脂肪族含氮碱ꎬ在植物生长发育及离
等ꎬ2023)ꎮ 荔枝产期集中ꎬ病虫危害严重等限制着 体再生 中 起 着 重 要 作 用 ( Rakesh et al.ꎬ 2021)ꎮ
产业的高质量发展ꎬ选育不同熟期、优质、多抗等优 Sathish 等(2019) 研究发现外源 PAs 促进了甘蔗
良品种是解决这些问题的根本途径ꎮ 传统育种方 (Saccharum spp. Hybrid)的体胚发生及再生效率的
式如杂交育种、实生选种等ꎬ具有耗费大、周期长、 提高ꎬ分别提高了 2 倍和 3 倍以上ꎮ Eldawayati 等
效率低等不足ꎬ基因编辑等生物技术可克服这些不 ( 2018 ) 发 现 枣 椰 ( date palm) EC 在 含 亚 精 胺
足ꎬ是荔枝育种的重要发展方向( Das & Rahmanꎬ (spermidineꎬ Spd)固体培养基上发育最好ꎬ体胚发
2010)ꎮ 高效的离体再生技术体系是生物育种的前 生数量在含腐胺( putrescineꎬPut) 的液体培养 最
提ꎬ但在荔枝上ꎬ经体胚发生途径获得再生植株的 多ꎮ 本课题前期研究发现ꎬ“ 妃子笑” 荔枝( Litchi
报道鲜少ꎬ主要是体胚诱导率低、畸形胚多导致萌 chinensis cv. Feizixiao ) 愈 伤 组 织 多 胺 氧 化 酶
发率低(Das et al.ꎬ2016ꎻ Wang et al.ꎬ2016ꎻ 秦雅琪ꎬ (polyamine oxidaseꎬ PAO)活性与体胚发生呈正相
2019)ꎬ阻碍了生物育种的应用ꎮ 因此ꎬ研究提高荔 关(吉训志ꎬ2019)ꎮ 进一步研究表明ꎬPAs 和相关
枝离体再生效率的技术并探索其作用机制ꎬ对促进 代谢酶的内源性变化与荔枝 EC 增殖及体胚诱导
荔枝生物育种发展具有重要的现实意义ꎮ 的不同发育阶段( 从愈伤组织到 EC、早期体胚诱
已 有 较 多 关 于 影 响 荔 枝 胚 性 愈 伤 组 织 导) 的结构相一致ꎻPut 及精胺( spermineꎬSpm) 是
(embryogenic callusꎬEC)增殖和体胚发生的因素的 荔枝 EC 中的主要 PAsꎬ体胚诱导过程中的 Put 及
研究ꎬ如基本培养基和碳源( Raharjo & Litzꎬ2007ꎻ Spd 含量整体上高于 EC 增殖阶段ꎻSpm 含量相反ꎬ
Das et al.ꎬ2016)ꎬ2ꎬ4 ̄D、玉米素及激动素等生长 EC 增殖过程中的 Spm 平均含量高于体胚诱导阶
调节因子(Puchooaꎬ2004ꎻMa et al.ꎬ2008ꎻ秦雅琪ꎬ 段ꎮ PAO 及二胺氧化酶( diamine oxidaseꎬDAO) 活
2019)ꎬ有机附加物( Yu et al.ꎬ2000ꎻWang et al.ꎬ 性与 Put 含量呈正相关( 王果等ꎬ2021a)ꎮ 更进一
2023ꎻ王果 等ꎬ2023) 等ꎬ 但 鲜 见 多 胺 ( polyamineꎬ 步研究发现ꎬ在 EC 增殖阶段添加 3 类 PAs 会抑制
PA)调控荔枝离体再生的报道ꎮ PA 是一类广泛存 荔枝体胚发生ꎬ而多胺抑制剂( D ̄精氨酸或环己