光照與吉貝素對蕹菜子葉擴展之影響

Effects of Light and Gibberellic Acid on the Cotyledon Expansion of Water Spinach (Ipomoea aquatica Forsk)

羅淑惠(Shwu-Huey Luo) ； 張永達(Yung-Ta Chang) ； 鄭湧涇(Yeong-Jing Cheng) ； 童武夫(Wu-Fu Tong)

《師大生物學報》 26卷 (1991/06) Pp. 20-33

https://doi.org/10.29812/BBNTNU.199106.0003

摘要

本研究以子葉鮮重及面積，做為測定離體子葉擴展之主要指標，用以探討光照與吉貝素（GA3）對蕹菜子葉擴展之影響。結果顯示子葉經0.1mM，GA3，處理後，在光強度34W / m^2及溫度30℃之實驗條件下，子葉擴展反應最為顯著。GA3與細胞分裂素（BA）皆能誘導離體子葉擴展，但兩者之作用機制不同，因為BA在光照或黑暗中對於子葉之擴展皆有顯著促進作用，而GA3則僅在光照下，才有明顯的擴展反應。子葉經GA3處理並在光照下生長五天後，其乾重量、DNA含量、及細胞數目方面，並無顯著增加，但是細胞大小方面、卻已由13um增至40um。另一方面，子葉經BA處理後，其細胞之平均直徑達50um，細胞數目及DNA含量的增加分別為94%及56%；甚至在黑暗中，BA處理的子葉仍然有顯著的擴展現象。實驗結果顯示，GA3可能是誘導子葉之細胞滲透勢（Osmotic potential）改變，因而引起子葉吸收水量之增加，由此導致子葉之鮮重與面積的增加，此乃GA3能促進子葉擴展之主要原因。

關鍵字

光照 ； 吉貝素 ； 蕹菜 ； 子葉擴展 ； 細胞分裂素

並列摘要

Fresh weight and area changes of excised cotyledons were used as the main indicators for the investigation of the effects of light and Gibberellic Acid (GA3) on water spinach cotyledon expansion. The most significant cotyledon expansion was observed when cotyledons were treated with both light (34W/m^2) and GA3 (0.1 mM) at 30°C.Significant expansion of excised cotyledons were induced by the treatment of GA3 or Benzyladenine (BA). However, the mechanisms of cotyledon expansion induced by GA3 and BA seemed to be different, because cotyledon expansion induced by BA was significant in both light and dark, while that induced by GA3 was prominent only in the light.Under light irradiation, the diameter of cells of five-days cotyledons treated with GA3 was increased from 13 um to 40 um, but no significant increase in dry weight, DNA content and cell numbers were observed. It was shown that the average diameter of cells of cotyledons treated with BA for 5 days reached 50 um and the cell numbers as well as the DNA content increased by 94% and 56% respectively, Furthermore, cotyledon expansion was also found by BA treatment in the dark.It was suggested that changes in osmotic potenital of cells in cotyledons which subsequently enhanced water uptake might play a role in the induction of cotyledon expansion and increase in fresh weight and leaf area by GA3 treatment.

並列關鍵字

Light ； Gibberellic acid ； Ipomoea aquatica ； Cotyledon Expansion ； Benzyladenine