硼對水耕胡瓜生育及數種酵素活性之影響

Effects of Boron on the Growth and Some Enzyme Activities of Hydroponically Grown Cucumber (Cucumis sativus L)

利用不同濃度（0, 0.05, 0.3, 4.0及12.0ppm）硼以水耕方式處理胡瓜‘喜燕’植株，藉以探討硼對胡瓜植體各部位生育之影響，並比較酚類化合物含量和數種氧化酵素活性之差異。試驗結果發現胡瓜對硼需求量甚低，0.05ppm便可維持良好的營養生長，但若欲得優良果實，則仍需0.3ppm方能有良好收穫。而缺硼易造成植株生長停止，根部前端之側根增加，莖基部縱裂，葉片硬脆，葉脈邊緣有黃斑，雄花生育不良，雌花無法產生。硼含量過多則極易造成胡瓜葉緣黃化，生長受抑制，開花不良，花粉發芽不佳，以及果形彎曲。缺硼時，胡瓜植體內酚類化合物、過氧化酶、多酚氧化酶活性增加，但吲哚乙酸氧化酵素在初期增加，後期卻減少。另外，葉片之過氧化酶之同功異構酶在缺硼之情況下，條帶數目增加且條帶濃度有加深現象。

The objective of this study was to investigate the effect of boron on the growth and physiology of cucumber 'Joy' treated with various concentrations (0, 0.05, 0.3, 4.0 and 12.0 ppm ) of the element. Results indicated that the boron requirement of cucumber is rather low. A boron concentration of 0.05 ppm seemed enough for the optimal vegetative growth of cucumber but for the best fruit quality, 0.3 ppm is more appropriate. Boron deficiency symptoms of cucumber are retarded plant growth, cracked stem base, brittle leaves, interveinal chlorosis, enhancement of lateral -root formation, abnormal development of male flower and the lack of female flowers. Excess boron may cause the marginal chlorosis of leaves, reduced pollen germination, and production of malformed fruits. In the boron-deficient cucumber plants, the phenolic compounds, activities of both peroxidase and polyphenol oxidase increased, however activity of IAA oxidase increased at the early stage of growth and decreased in the late stage. Furthermore, change in isozyme patterns of peroxidase was observed in the boron-deficient cucumber using gel electrophoresis, Bands intensity was enhanced in the deficiency treatment.