Effects of Nitrogen Status on Leaf Anatomy, Chlorophyll Content and Canopy Reflectance of Paddy Rice

氮營養狀態對水稻葉片解剖結構、葉綠素含量及植被反射光譜之影響

李裕娟(Yuh-Jyuan Lee) ； 楊純明(Chwen-Ming Yang) ； 章國威(Kuo-Wei Chang) ； 申雍(Yuan Shen)

《Botanical Studies》 52卷3期 (2011/07) Pp. 295-303

摘要

應用遙測技術適時提供田間作物氮營養狀態資訊，對於採行精準農業操作，減少過量施用氮肥所造成的環境污染問題非常重要。為能選擇最適當的因子，以建立推估作物氮營養狀態遙測模式，本研究利用不同氮肥用量處理，探討植體氮營養狀態對水稻葉片解剖結構、葉綠素含量及植被反射光譜之影響。研究結果指出，氮含量高的植體，不僅葉片葉綠素含量片較高，葉片也較厚、堅挺且不易捲縮，因此增強植被反射光譜在可見光區的吸收，且提高在近紅外光區的反射。利用植被反射光譜在紅光和近紅外光區的微分值，可以同時考量植體氮營養狀態對葉綠素含量和葉片解剖結構的影響，並降低背景土壤的干擾，因此比單純使用特定波段的反射值或波段比值更適合作為推估作物氮營養狀態迴歸模式的自變數使用。

關鍵字

遙測 ； 水稻 ； 葉片結構 ； 葉綠素含量 ； 氮營養

並列摘要

Precision agriculture can reduce the environmental pollution that results from over application of nitrogen (N) fertilizers by acquiring timely N status assessments of field plants through remote sensing techniques. To establish effective remote sensing models for plant N assessment, we carried out experiments using different rates of N fertilizer and examined changes in leaf anatomical characteristics, chlorophyll content and canopy reflectance behavior at the panicle initiation stage of paddy rice (Oryza sativa L. cv. Tainung 67). Results showed that plants with higher N content not only had higher chlorophyll content but also had thicker, flatter and more turgid leaves, which enhances visible light absorption while stimulating near-infrared reflection. Derivative type predictors, using the transition region from red and near-infrared wavebands, not only accounted for the changes in leaf chlorophyll content and structures induced by varied N content, but helped eliminate background soil interferences. Therefore, derivative type predictors may be more appropriate than reflectance values at specific band(s) and band ratios in establishing a robust model for plant N status assessment.

並列關鍵字

Chlorophyll content ； Leaf micrographic structure ； Nitrogen ； Paddy rice ； Remote sensing