冬小麦日光诱导叶绿素荧光的日变化规律探究

Diurnal variation of solar-induced chlorophyll fluorescence of winter wheat

利用自动化光谱观测系统获取的SIF数据,初步探讨了SIF日变化与光合有效辐射之间的关系,以及SIF在不同天气状况和土壤水分情况下的日变化规律.结果表明:SIF的日变化与光合有效辐射显著正相关,上午二者的相关系数达到0.9.晴天时,SIF的日变化有相似的变化规律,荧光的变化范围是0～0.5μW·cm^(-2)·nm^(-1)·sr^(-1),SIF的日变化呈单峰状态,一般在中午12:00左右达到峰值,基本呈现对称分布,06:00—12:00期间,冬小麦叶绿素荧光值逐渐增大,12:00—18:00期间,冬小麦叶绿素荧光值逐渐减小;阴天时受光照条件影响,荧光变化范围一般较小且不超过0.1μW·cm^(-2)·nm^(-1)·sr^(-1),日变化呈现无规律的波动状态.通过设置水分控制试验,发现在灌水前后,荧光日变化的幅度有较大的变化且对于土壤水分的变化反应敏感,SIF的日变化的峰值在灌水后迅速下降,之后逐渐上升并趋于稳定.本文的研究结果对于SIF的应用研究奠定了一定的基础,在探测植物的生长、病害及受胁迫等生理状况方面具有一定的参考价值.

Solar-induced chlorophyll fluorescence（SIF）has been widely used as an indicator of photosynthesis to monitor changes in vegetation at site-or region-scales.It is very important to study diurnal variation of SIF to further application of SIF.SIF of winter wheat was collected by automated spectrometer system with high spectral resolution.The relationship between SIF and photosynthetically active radiation（PAR）,SIF under different weather and soil water conditions were investigated.Diurnal SIF was found to show significant positive correlation with PAR（R=0.9）.In sunny days,SIF showed a consistent diurnal pattern with a hump shape,with variation from 0-0.5μW·cm^-2·nm^-1·sr^-1.It peaked at about 12 o＇clock with symmetrical distribution.SIF values of winter wheat gradually increased from 06：00-12：00,and decreased from 12：00-18：00.In cloudy days,diurnal variation of SIF showed irregular fluctuations with small ranges of no more than 0.1μW·cm^-2·nm^-1·sr^-1.It was also found that diurnal variation of SIF was sensitive to soil moisture,ranges of SIF values varied before and after irrigation.SIF peak decreased rapidly after irrigation,before gradual increase then leveled off.This study will provide some reference for the application of SIF,especially in the detection of plant growth,health and other physiological conditions.