晚霜冻影响下冬小麦冠层光谱特征与株高要素变化关系

冬小麦遭受晚霜冻害后,生理生态方面会发生显著变化,其中又以株高要素的变化最为显著。提取了包括红边位置、红边振幅在内的15个光谱特征参数,以及包括株高、穗长、穗下节间长和倒二节间长变化率4个株高要素,通过相关分析,筛选出与光谱特征相关性最好的株高变化率参数,并建立逐步回归模型。结果表明:仅有株高变化率在2013和2014年两期试验中均与光谱特征参数达到显著相关;将两期试验数据合并后,则穗长、穗下节间长和倒二节间长的变化率也均达到显著相关。综合考虑模型的Adj.R~2和显著性水平(Sig.)可知,模型拟合效果最好的是穗长变化率,其次是株高,穗下节间和倒二节间长变化率。比较模型的RMSE可知,模型预测精度最高的是穗下节间长变化率。该研究对在冻害胁迫条件下用光谱特征参数预测小麦株高各要素的变化提供了很好的参考,对研究晚霜冻害低温胁迫下冬小麦株高要素变化的规律具有指示性意义。

Relationship Between Hyperspectral Parameters of Winter Wheat Canopy and Plant Height Components under Late Frost Injury

After late frost injury ,the physiological and ecological aspects of winter wheat were changed ,among which the change of plant height was the most significant .In this research ,four plant height components ,including plant height ,ear length ,peduncle length ,and penultimate internode length ,as well as 15 hyperspectral parameters ,namely red edge position and the red edge amplitude ,etc were obtained .The change rate plant height components ,which has the best correlation with the hyperspectral parameters were selected by correlation analysis ,and then were used to establish stepwise regression model .The results showed that only the change rate of plant height was significantly correlated with the hyperspectral parameters in both two experiments in 2013 and 2014 .After the two experimental data were combined ,the change rates of spike length ,peduncle length and the penultimate internode length were also significantly correlated .Comprehensively considering the Adj .R2 and the significance level (Sig .) ,it can be seen that the best fitting model is the change rate of ear length ,followed by the plant height , the peduncle length and the penultimate internode length .Comparing the RMSE of the model ,it can be seen that the change rate of peduncle length got the highest prediction precision .The results of this study provide a good reference for the prediction of wheat plant height by hyperspectral parameters under freezing stress conditions .The results are of great significance to the study of the changes of plant height elements in winter wheat under low temperature stress .