半結球萵苣於缺磷逆境與不同光強度之生理反應

Physiological Responses of Semi-Heading Lettuce (Lactuca sativa L.) under Phosphorus Starvation and Different Light Intensity Conditions

郭美琳(Mei-Lin Kuo) ； 林淑怡(Shu-I Lin)

《臺灣園藝》 62卷1期 (2016/03) Pp. 33-48

摘要

本研究探討磷濃度及光強度對半結球萵苣生理反應之影響。水耕半結球萵苣於高光強度(300μmol．m^(-2)．s^(-1))與低光強度(100 μmol．m^(-2)．s^(-1))環境下之生長速率不同，對缺磷逆境之反應也相異。生長中期之植株在高或低光強度下缺磷5天，地上部與地下部之無機磷濃度以及地上部鮮重顯著下降，缺磷10天後，含水量與硝酸鹽濃度亦顯著降低、過氧化氫顯著增加；而在高光下缺磷5天時，葉綠素與類胡蘿蔔素顯著上升，低光下缺磷至10天才上升。生長後期植株在高或低光強度下缺磷5天，亦顯著降低地上部與地下部之無機磷濃度，但即使缺磷10天，其地上部鮮重、含水量以及葉綠素、類胡蘿蔔素、過氧化氫與硝酸鹽濃度皆無顯著變化。故對於確保半結球萵苣的產量與品質而言，於生長中期供應適當磷肥為必要，但於生長後期則不需再補充磷肥，可節省生產成本及維護農業永續性。

關鍵字

光強度 ； 含水量 ； 硝酸鹽 ； 過氧化氫 ； 葉綠素 ； 類胡蘿蔔素

並列摘要

This research aimed to explore the effects of phosphate (Pi) concentration and light intensity on the physiological responses of semi-heading lettuce. Semi-heading lettuce plants hydroponically cultured under high (300 μmol．m^(-2)．s^(-1)) and low (100 μmol．m^(-2)．s^(-1)) light intensities displayed different growth rates and responses to phosphorus starvation. During mid-growing stage, the shoot fresh weight and Pi concentrations of shoot and root were significantly decreased after Pi starvation under either high or low light intensities for five days. The water content and nitrate concentration were notably decreased and the hydrogen peroxide concentration was significantly increased after Pi starvation for ten days. Under high light intensity condition, the chlorophyll and carotenoids concentrations were significantly increased after Pi starvation for five days, but under low light intensity condition it took ten days of Pi starvation to increase the concentrations. During late growing stage and under either high or low light intensities, shoot and root Pi concentrations were remarkably decreased after Pi starvation for five days, but no significant differences could be seen in shoot fresh weight, water content, chlorophyll, carotenoids, hydrogen peroxide and nitrate concentrations even after Pi starvation for ten days. Therefore, to ensure yield and quality of semi-heading lettuce, proper supply of Pi fertilizer during mid-growing stage is essential, but it is unnecessary to supply Pi fertilizer during later growing stages, as the production cost can be reduced and agricultural sustainability can be maintained.

並列關鍵字

light intensity ； water content ； nitrate ； hydrogen peroxide ； chlorophyll ； carotenoids