水分管理對不同水稻品種穀粒鎘累積之影響

Effect of Water Management on the Accumulation of Cadmium in Rice Grain of Different Rice Cultivars

許健輝(Chien-Hui Syu) ； 鄭佳怡(Chia-Yi Cheng) ； 劉滄棽(Tsang-Sen Liu) ； 吳東鴻(Dong-Hong Wu) ； 郭鴻裕(Horng-Yuh Guo) ； 林毓雯(Yu-Wen Lin)

《台灣農業研究》 68卷4期 (2019/12) Pp. 315-326

https://doi.org/10.6156/JTAR.201912_68(4).0005

摘要

水稻為亞洲地區主要的糧食作物，因此針對降低榖粒鎘累積的研究近年來受到許多關注。水分管理被認為可有效降低稻米鎘累積的農藝管理方法之一，此法不但對環境友善，農民也能夠自行操作。然而，過去較少研究比較不同水分管理對不同水稻品種鎘累積的差異。因此，本研究目的為探討水分管理對於土壤鎘有效性，以及不同水稻品種鎘累積及產量的影響。本試驗使用2種水分管理（慣行、湛水）及4個水稻品種（「台南11號」、「台東30號」、「台中秈10號」、「桃園3號」），試驗期間測定土壤氧化還原電位、孔隙水鎘濃度、稻穀產量及植株鎘濃度。試驗結果顯示，相較於慣行管理，湛水管理可有效地降低土壤孔隙水鎘濃度，並降低鎘在根部、地上部及糙米的累積，降低程度分別達59.1-90.7%、48.9-93.9%及43.0-93.9%。由轉移係數的結果可知，湛水管理降低糙米鎘累積的機制為降低土壤的鎘有效性，而非降低鎘在植株內的轉移能力。本試驗結果證實，湛水管理的確可有效降低稉稻及秈稻品種糙米的鎘累積，因此建議於含鎘的水稻田增加土壤湛水的時間，將可顯著減輕糙米鎘累積的濃度。

關鍵字

鎘 ； 水稻 ； 水分管理 ； 田間試驗 ； 水稻品種

並列摘要

Rice is a major staple crop in Asia area. The studies aimed at reducing cadmium (Cd) accumulation in rice grain have received much concern in recent years. Water management is a well-known agronomic practice for reducing Cd accumulation in rice grain, which is not only environment-friendly feasible but also easy to operate by farmers. However, there were few studies comparing the differences in Cd accumulation in rice plants among various rice cultivars under different water managements. Therefore, the objective of this study was to investigate the effect of water management on the Cd availability in soils, Cd accumulation in rice plants and grain yield of different rice cultivars. Two water management methods (conventional and flooded) and four rice cultivars ('TN11', 'TT30', 'TCS10' and 'TY3') were used in this study, and the soil redox potential, Cd concentration in pore water, grain yield and Cd concentration in rice plants were determined during the experimental period. The results of this study indicating the flooded treatment can effectively reduce the Cd concentration in pore water, and further decrease the Cd accumulation in the root (59.1-90.7%), shoot (48.9-93.9%) and brown rice (43.0-93.9%), compared with conventional practice. Based on the results of translocation factors, it indicates that the mechanism of flooded treatment to reduce Cd accumulation in brown rice is the decrease of Cd availability in soils, rather than reduce the translocation capability of Cd in plants. The results of this study confirm that flooded treatment can effectively reduce Cd accumulation in brown rice of japonica and indica cultivars. Therefore, it suggests that the Cd accumulation in rice grain will be reduced markedly through increasing the flooded time in Cd-containing paddy field.

並列關鍵字

Cadmium ； Paddy rice ； Water management ； Field experiment ； Rice cultivar