臺灣博碩士論文加值系統

本試驗以不耐浸水的植物苦瓜(Momordica charantia L.)為材料，探討在
浸水逆境下其形態、生理及生化反應，及可能的傷害機制。浸水造成苦瓜
下胚軸橫截面積及不定根數目的增加。根部呼吸率在浸水 1天處理後即降
至對照組之42% 。根部酒精脫氫酵素活性及酒精含量在 3天浸水處理後達
到最高值；而且，一個新的酒精脫氫酵素同功異構酵素因浸水而誘導出來
。持續浸水處理 8天後，原有根系完全死亡。浸水初期酒精大量的累積可
能是造成根系死亡的原因。苦瓜幼苗葉片之二氧化碳交換率、氣孔導度、
蒸散速率、可溶性蛋白含量、葉綠素含量、Rubisco 活性及Rubisco 含量
皆有明顯下降的現象，氣孔導度與二氧化碳交換率呈正相關 (R square=
0.92)。 然而葉片細胞間隙二氧化碳濃度於浸水 6天後由對照組的 240
.mu.bars 升至380 .mu.bars。葉片暗呼吸的升高可能為導致葉片細胞間
隙二氧化碳濃度升高的主因。而且，在浸水處理的苦瓜葉片明顯有澱粉的
累積。這些結果顯示，氣孔及代謝上雙重因子共同造成在浸水逆境下，二
氧化碳交換率的下降。 Rubisco 活性及Rubisco 含量變化呈正相關 (R
square=0.89)。此外，葉片細胞間隙二氧化碳濃度的提高可能造成在浸水
逆境下Rubisco 活化百分比的下降。

Flooding of bitter melon (Momordica charantia L.), a
flood- intolerant plant, induced several morphological and
physiological changes.Hypocotyl cross sectional area and number
of adventitious roots significantly increased after 4 days of
flooding. On the first day of flooding, root respiration
rate dropped to 42% of control value. Activity of alcohol
dehydrogenase (ADH) and internal ethanol concentrations
increased gradually and reached a maximum level at the third
day of flooding. Furthermore, a new ADH isozyme was induced
as a result of flooding. Continuous flooding lead to death
of seminal root system after 8 days of flooding. The
accumulation of ethanol may result in death of root root
system. Leaves of young seedlings of bitter melon exhibited
reduced leaf carbon dioxide exchange rate (CER), stomatal
conduc- tance, transpiration rate, soluble protein content,
chlorophyll content, ribulose-1,5-bisphosphate carboxylase/
oxygenase(Rubisco) activity and Rubisco content. Stomatal
conductance was positively correlatedwith CER (R square=0.92).
However, the internal carbon dioxide concentration (Ci) of
leaf tissues of flooding-treated plants increased from 240
.mu.bars at day 0 up to 380 .mu.bars at day 6 of flooding.
Furthermore, starch was found to accumulate in chloroplasts of
the flooding-treated leaves. These results indicate that
both stomatal and metabolic factors are responsible for the
reduction in CER during flooding stress. Dark respiration of
leaf increased concomitantly with Ci elevation. Rubisco
activities were shown to linearly correlate with Rubisco
content (R square=0.89) and the percent activation of Rubisco
declined. The elevation of Ci may be involved in lowering
the percent activation of Rubisco during flooding stress.