山櫻花種皮和內果皮萃取液對種子發芽的效應

Abstract

摘 要

種子休眠是植物最重要的生理現象之一，但是涉及休眠機制的許多關鍵因子至今仍不明朗。我們利用臺灣原生植物――山櫻花種子為材料，探討種子休眠的問題。山櫻花種子呈現深度休眠的特性，研究重點是利用山櫻花種子之種皮和內果皮的萃取液，闡明種皮和內果皮所含的化學物質在山櫻花種子休眠上所扮演的角色。有許多研究報告發現胚在休眠控制上的重要性，例如阿拉伯芥、蕃茄和菸草等。但我們的研究顯示山櫻花種子胚本身不是維持休眠的主因，反而是來自種子的種皮和內果皮。藉由這些種皮和內果皮之萃取液對阿拉伯芥種子發芽和山櫻花胚生長的研究，結果證實有抑制作用，且層積處理可改變種皮和內果皮內之抑制物質對種子發芽的抑制能力。我們的研究數據顯示，種皮和內果皮這類來自母系的組織在山櫻花種子的休眠上扮演極關鍵的角色。

ABSTRACT

Seed dormancy is one of the most pivotal physiological phenomena of the plants. But many key factors involved in the mechanism of dormancy are still not well known. The dormancy seeds of Prunus campanulata Maxim, a native species in Taiwan, was selected to study the mechanism of dormancy. We focus on the extracts of testa and endocarp of the seeds to elucidate the chemical roles on the seed dormancy of P. campanulata. There are many reports usually emphasizing the importance of embryo in controlling dormancy of plants such as Arabidopsis, tomato and tobacco. But our results showed that the P. campanulata embryo itself could not remain dormancy without intact testa and endocarp, by contrast, the growth of embryo could be repressed by the extracts of testa and endocarp from fresh P. campanulata seeds. Via the effect of the testa and endocarp extracts of P. campanulata from various stratification treatments on the germination of Arabidopsis thaliana seeds, we confirmed that miscellaneous stratifications can alter the repressive ability of endocarps and testae for germination. All these data showed that the P. campanulata testa and endocarp that are derived from the maternal original tissue play an essential role in seed dormancy.