外源喜树碱对植物叶片气孔导度的影响

前人研究表明,保卫细胞微管系统在气孔运动中起到重要作用:保卫细胞质膜上内向K⁺通道的正常活性有赖于微管的正常解聚/聚合的动态变化,微管系统可能通过调节保卫细胞K⁺通道而控制气孔运动,即微管解聚导致内向K⁺通道关闭,保卫细胞无法因膨压调节吸收水分而抑制气孔开放。有学者认为,喜树碱或其类似物能够与微管蛋白结合,并降低微管结构稳定性,其机制则可能是抑制细胞高分子量微管结合蛋白对微管组装的辅助作用,但这方面的实验证据相对匮乏。因此,为了进一步研究喜树碱的生态生物化学功能,我们采取叶面喷施喜树碱和PEG模拟干旱诱导气孔关闭的方法,研究了外源喜树碱对喜树幼苗气孔导度的影响,同时以没有内源喜树碱的烟草为实验材料进行了对照研究。研究结果表明:0.0115mmol·L^-1的喜树碱水饱和溶液对喜树和烟草幼苗叶片气孔导度的影响规律一致,均表现出明显的抑制气孔开放的效果,这为喜树碱与微管蛋白结合提供了部分证据。

Spray Camptothecin impact the stomatal movement of leaves of plant

Some researchers suggested that the microtubule has an important effect on stomatal movement. The K⁺ channel activity of cytoplasmic membrane of guard cell was dependent on polymerization and depolymerization mobile changed of microtubule. Microtubule system may control stomatal movement induced by regulating the K⁺ channel of guard cell. Microtubule dispolymeric leads to the K⁺ channel closed. Guard cell could not absorb water so that it will inhibit stomata open. Some scholars regarded that Camptothecin(CPT) and its analogue could associate with microtubule, reduce the structure stability of microtubule. The mechanism maybe inhibit high molecule weight microtubule associated protein to associate with microtubule. But we were short of the deep proofs of studying the ecological biochemistry function of CPT; we were spraying 0.011 5 mmol·L^-1 CPT solution on leaves and used 10% PEG₈₀₀₀ solution to stimulate drought stress. The research results indicated that sprayed 0.011 5 mmol·L^-1 CPT solution and 10% PEG₈₀₀₀ could induce Camptotheca acuminata and Nicotiana tabacum seedlings stomatal to close. We suggested that CPT could associate with microtubule, induce stomatal movement.