The leaf reflectance spectral characteristics of Chamaecyparis obtusa var. formosana at the Chi-Lan Mountain site

• Main Authors: Hsien-Yi Chang, 張憲一
• Other Authors: Shih-chieh Chang
• Format: Others
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/52109998174283011717

碩士 === 國立東華大學 === 自然資源與環境學系 === 102 === Chamaecyparis obtusa var. formosana is distributed over mid-elevation cloud forests of Taiwan. There are some preliminary studies of Chamaecyparis obtusa var. formosana photosynthetic characteristics at the Chi-Lan Mountain site of northeastern Taiwan. This study explored photosynthetic characteristics of Chamaecyparis obtusa var. formosana through the rapid, convenient and non-destructive leaf reflectance spectra method. The first purpose of this study was to establish the relationship between optical indices and ecophysiological parameters of Chamaecyparis obtusa var. formosana. The optical indices included PRI, NDVI, CI and mND705. The second purpose was to study the temporal variation of leaf reflectance spectral characteristics of Chamaecyparis obtusa var. formosana. The third purpose was to study the spatial heterogeneity variation of leaf reflectance spectral characteristics of Chamaecyparis obtusa var. formosana. The study found that PRI had a good relationship with light use efficiency(LUE) and photosystem II quantum yield(ΦPSII), the R2 value was 0.71 and 0.81, respectively. But the relationship was weak when PRI decreased to below zero. Leaf chlorophyll content had the highest correlation with mND705(R2=0.64), followed by CI(R2=0.57), and NDVI was not correlation with chlorophyll content. Temporal variations showed that PRI had significantly low value in winter than other seasons. The seasonal variability of PRI was majorly affected by mND705, and there was a significant positive correlation(R2=0.69) between them. Air temperature had a weaker correlation with PRI. Spatial variations showed that the mature leaf of low level had highest mND705, this represent the leaf had high chlorophyll content at the low canopy. We also found that the mND705 of young leaf had no difference at different canopy height. The study revealed that leaf reflectance spectral analysis provide s a rapid, non-destructive method to monitor light use efficiency and pigment content of Chamaecyparis obtusa var. formosana. However, the PRI had a weaker relationship with light use efficiency when PRI decrease to below zero. We must pay attention to the problem when we select PRI for estimating light use efficiency of Chamaecyparis obtusa var. formosana in the future.