低溫逆境下植物體還原氧化?與蔗糖合成?活性的改變

Abstract

本研究是以14天大之抗冷性豌豆(Pisum sativum L C V.)與5天大冷敏感性綠豆(Vigna radiata L.)幼苗為實驗材料，分別比較過氧化氫?(Peroxidase)，催化?(Catalase)，超氧物歧化?(superoxide dismutase SOD)及蔗糖合成?(sucrose synthase SS)等酵素活性之變化，藉此探討這二者植物受低溫逆境下所?生之生理生化反應。由實驗結果得知四種酵素活性的變化如下：豌豆的過氧化氫?活性在4℃和10℃處理下均比28℃之對照組低。10℃處理的平均活性比28℃處理的低約25％，而4℃處理的平均比28℃低約10％。綠豆的過氧化氫?在10℃下卻比28℃平均高約40％，而4℃處理的平均活性與28℃（對照組）相近。 豌豆的催化?活性在4℃處理下，會隨著處理的時間增長逐漸減低，而平均活性與28℃相差不大。而10℃處理的，卻會隨處理的時間增長，活性變得愈大，在96小時幾乎為28℃的一倍。綠豆的催化?，則在4℃處理下活性減低的很明顯，其平均活性為28℃的25％，而10℃處理的，則其活性下降較平緩，平均活性約為28℃的80％。 豌豆的全葉超氧物歧化?整個活性變化與28℃相近，其中Mn-SOD活性會受低溫（4℃）影響而降低，平均活性（對照組）為28℃的一半，而10℃冷馴化處理的活性稍有影響，平均約為28℃的80％。但Fe-SOD活性卻因低溫而上升，尤其是4℃，Fe-SOD的活性增加，使整個SOD的活性跟28℃處理的相差不大。CuZn-SOD在4℃處理下活性有逐漸上升跡象，但10℃卻是緩慢下滑。葉綠體抽取的超氧物歧化?活性，其中Mn-SOD不因低溫影響活性，CuZn-SOD則因低溫影響之下而增加，但不明顯。綠豆的全葉超氧物歧化?的活性變化受低溫影響不大。其中Mn-SOD因低溫（4℃）影響，活性平均只為28℃的75％而10℃處理卻有逐漸上升的趨勢。Fe-SOD和CuZn-SOD均受低溫影響而上升，但幅度不大。葉綠體抽取的SOD，其中Mn-SOD在10℃下，活性增加其增加量平均為28℃的20％，而4℃則下降，但不很大。而CuZn-SOD活性則不因低溫而改變。 在豌豆的蔗糖合成?在10℃下所受的影響不大。但在4℃處理，其活性則有明顯的增加，平均增加量為20％。然而綠豆的蔗糖合成?，在10℃下，活性雖有上升趨勢，但並不高。以4℃處理的則活性減低，平均約為28℃的3/5。 由本研究結果顯示，在低溫逆境下植物體內的超氧物歧化?及過氧化氫?活性變化不大。

This study deals with the responses of both mungbean (cold-sensitive) and pea (cold-resistant) to low temperature, mainly in the chilling range of about 4℃ and cold-acclimation range of about 10℃. This article concerns the comparasion between mungbean and pea on peroxidase, catalase, superoxide dismutase (SOD), and sucrose synthase (S.S) activities at 4℃, 10℃ and 28℃. In pea leaves the average activity of peroxidase at 10℃ is lower than that at 28℃ about 25%, and the average activity of peroxidase at 4℃ is lower than that at 28℃ about 10%. On the other hand, mungbean leaves the average activity of peroxidase at 10℃ is higher than that at 28℃ about 40%, at 4℃ it is similar to that at 28℃. In pea leaves the average activity of catalase at 4℃ is slightly lower than that at 28℃, but at 10℃ it increases nearly two times as large as that at 28℃ after 96 hours treatment. While mungbean is chilled at 4℃, the average activity of catalase is decreased apparantly compared with that at 28℃, but at 10℃, it slightly lower down to 80% of that at 28℃. According to prothetic metals, three types of SOD have been found they are: CuZn-, Mn- and Fe-containing enzymes. When pea leaves are treated with chilling and cold-acclimation, total SOD activity is similar to it at 28℃. But Mn-SOD activity chilled at 4℃ decreases to half times as large as it at 28℃, and at 10℃, it decreases to 80% of it at 28℃. Meantime upon chilling effect, Fe-SOD activity increases until the totaal SOD activity is common to that at 28℃. CuZn-SOD activity is not affected by low temperature. In chloroplast SODs activities, CN-insensitive Mn-SOD is not affected by low temperature, but CN-sensitive CuZn-SOD is affected to increase. At 4℃ and 10℃, total SOD activities in mungbean leaves change slightly. Mn-SOD activity is affected by chilling that decrease to 75% compared to that at 28℃, but it increases slightly during cold-acclimation. Fe-SOD and CuZn-SOD activities increase during low temperature. treatments. In chloroplast, the average activity of CN-insensitive Mn-SOD increase to 120% compared to that at 28℃ during cold acclimation, but only slightly decreased under 4℃ treatment. On the contrary, CN-insensitive CuZn-SOD activity is not affected by low temperature. In pea leaves cold -acclimation does not effect S.S activity, but it progressively increase at 4℃. While in mungbean leaves chilled at 4℃ S.S activity decreases to 60% of that at 28℃, but that slightly increase during cold-acclimation. This conclusion is that chilling stress does not effect superoxide dismutase and peroxidase activities.