水稻成熟过程中高光谱与叶绿素、类胡萝卜素的变化规律研究

Variation law of hypersprctral data and chlorophyll and carotenoid for rice in mature process

通过大田和室内试验 ,测定了 2个品种、3个供氮水平处理的水稻冠层、主茎剑叶、完全展开倒三叶和穗在成熟过程中的不同时期的高光谱反射率及对应叶片和穗的叶绿素、类胡萝卜素含量。结果表明 :不同供氮水平的水稻冠层和叶片光谱差异明显 ,其叶片的叶绿素、类胡萝卜素含量随供氮水平的提高而增大 ;冠层光谱反射率随发育期推移在可见光范围内逐渐增大 ,在近红外区域逐渐降低 ;穗光谱的红边位置象冠层、叶片光谱一样也存在“蓝移”现象 ;叶片叶绿素、类胡萝卜素含量和高光谱植被指数VI1(R990 /R553 )、VI2 (R12 0 0 /R553 )、VI3 (R750 /R553 )、VI4(R670 /R440 )和VI5 (R553 /R670 )呈S形变化规律 ;叶片和穗的高光谱植被指数VI1、VI2、VI3、VI4、VI5、PRVI、PSSRa、PSNDa和λred与其叶绿素、类胡萝卜素含量之间存在极显著相关。这表明能用高光谱方法来估算水稻叶片和穗的叶绿素、类胡萝卜素含量 ,它为水稻品质遥感监测提供依据。

The hyperspectral reflectances of the canopy, the flag leaf, the third unfolding leaf from the top and ear of the main stem of two varieties of rice were measured by an ASD FieldSpec Pro FR^(TM) in field and indoor under 3 nitrogen supply levels in mature process. The concentrations of chlorophyll and carotenoid of leaves and ear corresponding to the spectra were determined by biochemical method. The correlation between the pigment concentrations and the nitrogen supply level and the hyperspectral data of rice were analyzed. The spectral difference were clear for the canopy and leaves of rice under different nitrogen supply levels, and the concentrations of chlorophyll and carotenoid of leaves increase along with nitrogen supply level. The canopy spectral reflectance were gradually getting larger in the visible region and smaller in the near infrared region as the growth stage went on. There were ‘blue shift’ phenomena for the position of red edge of the spectra of ear as that of canopy and leaves. There were S shape changes for the concentrations of chlorophyll and carotenoid of leaves and their hyperspectral vegetation indices VI1(=R_(990)/R_(553)), VI2(=R_(1200)/R_(553)), VI3(=R_(750)/R_(553)), VI4(=R_(670)/R_(440)) and VI5(=R_(553)/R_(670)). The concentrations of chlorophyll and carotenoid of leaves and panicles were very significantly correlative to the hyperspectral vegetation indices VI1, VI2, VI3, VI4, VI5, PRVI(=R_(800)/R_(553)), PSSRa, PSNDa and λ_(red) (the red edge position). This indicated that the concentrations of chlorophyll and carotenoid of leaves and panicles of rice could be estimated by the hyperspectral method. It could provide basis for monitoring rice quality by remote sensing.