新興污染物鎵和銦對水耕栽培水稻生長之影響

Abstract

鎵和銦之化合物常被應用於半導體及光電產業，然而，人們可能會經由食物鏈而攝食到含有鎵和銦的食物，導致健康風險增加。現今國內外鮮少有鎵和銦對作物影響的相關研究，因此本研究以水耕試驗，探討鎵和銦對於水稻幼苗生長之影響及其對兩元素的吸收和累積。水稻先於修正半強度木村氏B養液育苗兩星期後，再移植至含有鎵和銦的修正全強度木村氏B養液進行暴露，處理分為：鎵處理 (控制組、1、3、5、10、15 mg L-1)、低濃度銦處理 (控制組、0.04、0.08、0.1、0.15、1、2 mg L-1) 與高濃度銦處理 (控制組、0.1、1、3、5、10 mg L-1)。鎵與低濃度銦處理於11、12月種植，共40天；高濃度銦處理則於7、8月種植，共25天，各處理水稻種植於台灣大學人工氣候室，環境條件為日溫25℃、夜溫20℃、相對溼度70-95%、自然光。結果顯示水稻會吸收鎵和銦，且兩元素能在植體內被運輸，但大部分累積於根部。鎵濃度低於10 mg L-1時，水稻之株高生長量、根伸長量、地上部生質量和根生質量會被促進，而銦濃度為0.08 mg L-1時，水稻之株高生長量、根伸長量、地上部生質量和根生質量會受到抑制。鎵處理水稻SPAD值會增加，銦處理水稻則是在高濃度處理之1 mg L-1，SPAD值會顯著下降。本研究亦發現鎵處理下會促進水稻對氮和鉀的吸收，但會減少對鐵、錳和磷的吸收，低濃度銦處理下會減少水稻對鈣、鎂和鐵的吸收，而高濃度銦處理下則會使水稻對鈣、鎂、鐵、錳和鋅的吸收受到抑制。

Gallium (Ga) and indium (In) compounds are commonly used in semiconductor manufacturing industry and electro-optical industry. Human beings may also expose to Ga and In via food-chain, which could lead to increase of health risks. To our best knowledge, there are few studies to investigate the effects of Ga and In on the growth of crops. Thus hydroponic experiments were conducted to evaluate the effects of Ga and In on the growth and uptake of these two elements of rice seedlings. Rice (Oryza sativa L.) seedlings were cultivated in modified half-strength Kimura B nutrient solutions for two weeks, after that rice seedlings were exposed to modified full-strength Kimura B nutrient solutions containing various Ga and In concentrations. The treatments included: Gallium (control, 1, 3, 5, 10, 15 mg L-1), Low-In concentration (L-In) (control, 0.04, 0.08, 0.1, 0.15, 1, 2 mg L-1) and High-In concentration (H-In) (control, 0.1, 1, 3, 5, 10 mg L-1) treatments. Ga and L-In treatments were grown in Nov. and Dec. for 40 days; H-In treatment was grown in July and Aug. for 25 days. All hydroponic cultures were performed in the Phytotron of National Taiwan University at day 25°C / night 20°C, relative moisture 70-95% and natural light. The results revealed that rice seedlings could absorb Ga and In, and transfer these two elements from root to shoot in the plant, but most of them were accumulated in root. Gallium stimulated growth of rice seedlings when concentration was below 10 mg Ga L-1, however, growth of rice seedlings was inhibited by In as concentration reached 0.08 mg L-1. SPAD value increased in Ga treatment, nevertheless, chlorosis would occur when concentration of In was 1 mg L-1 in H-In treatment. Our results suggested that Ga might promote N and K uptake, but decrease the uptake of Fe, Mn and P by rice seedlings. The absorption of Ca, Mg and Fe in rice seedlings was inhibited in L-In treatment. The uptake of Ca, Mg, Fe, Mn and Zn by rice seedlings was inhibited in H-In treatment.