利用冠层和叶片水平的反射光谱研究模拟酸雨对小麦的影响

通过光谱分析技术,研究了模拟酸雨（SO-42：NO-31=5：1）对小麦产量和生理特性的影响。结果表明,模拟酸雨伤害了小麦叶片的结构和功能,降低了叶绿素含量和光合速率,从而显著降低了小麦的产量,经过pH为2的酸雨处理后的小麦产量降幅达19.1%。通过对植被指数的分析可以看出,小麦冠层叶绿素含量在开花期以后逐渐降低,而旗叶的叶绿素含量则在灌浆期以后开始下降,两者的下降幅度都随着酸雨pH的下降而增大。光合速率表现出与叶绿素含量相同的变化。另外,对小麦产量与不同生育期冠层和叶片水平的植被指数的相关分析表明,灌浆期的小麦冠层水平的NDVI、mND705和WI与酸雨处理后小麦的产量显著相关。总之,利用光谱分析技术可以快速、无损伤地监测不同酸雨处理对小麦的生长和营养状况的影响。

Study on the Effects of Simulated Acid Rain on Wheat Using the Spectral Reflectance at Canopy and Leaf Level

Acid rain has been considered as one of the most serious environment problems.The traditional monitor methods are expensive and time consume.Recently,the spectral reflectance technical has been developed and used to reflect the effects of the environment on plants rapidly and non-invasively.However,relationship between spectral reflectance and effects of acid rain on wheat is still limited.In this paper the effects of simulated acid rain（SO-24：NO-13=5：1） on the grain yield and physiological characteristics of wheat were studied using spectral reflectance.The results showed that the simulated acid rain decreased the grain yield due to damaged leaf internal structure and function,decreased chlorophyll content and photosynthesis.The grain yield was also reduced by 19.1% in the wheat treated with simulated acid rain of pH 2.The net photosynthetic rate and the pigment content decreased after flowing at the canopy level but it decreased after filling at the leaf level.The decrease extent at both canopy and leaf levels was enhanced by the decreasing of pH in the simulated acid rain.In order to make the best use the spectral reflectance to reflect the effects of the acid rain on wheat,the correlation between the grain yield and the different vegetation indexes water index（WI）,the modified simple ratio（mSR705）,photochemical reflectance index（PRI）,normalized difference vegetation index（NDVI）] from the spectral reflectance of canopy or leaf level at different development stage was analyzed.The results showed that a significant correlation was observed between grain yield and NDVI,mND705 and WI both at canopy and leaf level at the filling stages.In conclusion,the technique of spectral reflectance can be used to reflect the growth,nutrition condition and grain yield of the wheat under the influence of acid rain.