樱桃叶单宁的分布及累积特征

Distribution and Accumulation of Tannins in Cherry Leaves

为了解樱桃叶单宁积累的特征,用组织化学和超微技术对幼叶与成熟叶中的单宁积累及分布特点进行了观察分析,结果表明,樱桃幼叶和成熟叶均积累单宁,积累单宁的细胞类型有表皮细胞、叶肉细胞和维管薄壁细胞。叶发育阶段不同,单宁分布模式略有差异:在各种组织尚未完成分化的幼叶中,维管组织、表皮以及两者之间的支持组织积累较多单宁,将来分化为叶肉组织的细胞积累单宁较少。在成熟叶中,叶肉细胞积累单宁较多,而维管组织和表皮只积累少量单宁。单宁在液泡中积累,被限制在液泡内,不向细胞质中扩散,从而不会影响细胞质中蛋白质的功能。归纳起来,不同发育阶段叶片均积累单宁,但单宁分布模式随叶片发育状态而发生微小变化,樱桃叶具有以单宁为基础的防御紫外线伤害和病原菌侵染机制。

Cherry leaves were characterized by means of histochemistry and ultramicroscopy,to understand the distribution pattern of tannins and the effect of development on tannin accumulation.Both young and mature leaves accumulated tannins.Tannin-accumulating cells included epidermal cells,mesophyll cells,and vascular parenchyma cells.In young leaves,tannin accumulation was more in amount in vascular tissues,epidermis,and cells between the vascular tissue and epidermis than in tissues destined to become mesophylls.In mature leaves,however,mesophyll cells contained more tannins than epidermal cells and vascular parenchyma cells.Tannin accumulation occurred in vacuoles and did not move into the cytosol,and therefore would not interact with proteins to damage their functions.In summary,leaf development did not stop tannin accumulation,and tannin accumulation was not tissue specific.The observation suggested that cherry leaves possess tannin-based mechanism for protection against UV damage and microbe infection.