氮肥及鉻對水稻幼苗生長與反射光譜之影響

土壤重金屬會在植株內累積，並藉由攝食進入人體而產生危害，可見監測系統的建立有其必要性，因此希望能建立即時且非破壞性之監測方式以預估土壤有效性重金屬汙染濃度與植體累積金屬含量。本研究以水稻（Oryza sativa）品系台中秈10號及台稉9號（TCS10 and TK9）幼苗為材料，以50、100及200 μM之氮素濃度分別與鉻（0、100、200 及500 μM）重金屬進行栽培試驗，藉此來模擬田間不同濃度氮肥管理下，土壤溶液中有效性重金屬對水稻幼苗造成之影響，處理一周後測定葉面反射光譜，以反射率計算植生指數（vegetation index），結合地上部植體重金屬含量資料進行一次與二次多項式回歸分析，並從中建立預測模型。結果顯示受重金屬逆境植株在500-675 nm之黃綠光波段間反射率普遍增加，並在680-750 nm之紅光臨界區間會因為受重金屬逆境反射率普遍往短波長方向位移，產生紅光臨界藍移（blue shift of red edge）可做為植株是否受逆境之參考；氮素處理在100與200 μM時較為顯著，其反射率會比氮濃度50 μM處理組來得低，此外675nm以上之波段中，各重金屬處理組合之反射光譜一次微分波峰質在高氮濃度下普遍往長波長方向位移，產生紅光臨界紅移（red shift of red edge）。以常用波段或敏感波段計算之植生指數與植體重金屬濃度間建構線性及多項式模型，其中又以多項式模型較佳且具顯著相關性。因此利用反射光譜計算植生指數，非破壞性預估土壤有效性重金屬汙染物濃度與及植體累積重金屬含量，可能為有效可行之方法。

關鍵字

水稻幼苗；重金屬鉻；反射光譜；植生指數；氮素；多項式模型

並列摘要

Accumulation of toxic heavy metals in plants is harmful to human health through the food chain cycle. Therefore, it's necessary to establish a heavy metal monitoring system. The purpose of this study is the establishment of a model based on reflectance spectra to predict bioavailable heavy metal in soil and metal accumulation in shoots. Hydroponically cultivated rice seedlings of two cultivars (Oryza sativa L. cv. Taichung Sen 10 and Taiken 9) were treated with several combinations of nitrogen (N) (50, 100, and 200 μM) and chromium (Cr) (0, 100, 200 and 500 μM). The reflectance spectra of leaves were recorded and used to calculate vegetation indices to observe the relation between vegetation indices and the heavy metal concentration in shoots. The result indicated that heavy metals stress inhibited shoot length of rice seedlings. At high metal concentration, the reflectivity in 500-675 nm of yellow green light would increase and blue shift of red edge would happen at the same time. Additionally, for the treatment effect of high nitrogen concentration, the reflectivity in green light and red light would decreas, and red shift of red edge would happen at the same time. The linear and quadratic models were constructed from the relation between heavy metal concentration of shoots and vegetation index. The results showed that quadratic model has more significant correlation in both sets of variables. Therefore, it appears possible to create indices using reflectance spectra for non-destructive estimation the concentration of bioavailable heavy metal in soil and accumulation amount in shoot.

並列關鍵字

heavy metal(Cr) ； reflectance spectra ； rice seedlings ； nitrogen ； vegetation index ； quadratic model

國際替代計量

氮肥及鉻對水稻幼苗生長與反射光譜之影響

全文下載

主題瀏覽