植被光能利用率(LUE)是估计植被初级生产力(GPP)和净初级生产力(NPP)模型的一个重要输入,准确地估计LUE对于生态学研究有重要的意义.由于LUE随环境的变化关系十分复杂,现有的LUE估算模型过于粗糙简单,而通过遥感直接估计LUE将会更加可靠.研究表明,光化学反射植被指数(PRI)与LUE有很好的相关性,故PRI在利用遥感估计LUE方面具有极大的潜力.但是很多研究也发现了PRI-LUE的关系不够稳健,受许多因素的干扰,比如物种构成、冠层结构及大气等.因此,PRI的广泛应用还需要更多的研究.本文首先介绍了PRI的定义及PRI随LUE变化的生理机制,再综述了一些利用遥感手段建立PRI-LUE关系的例子,然后分析了影响PRI-LUE关系的各种干扰因素,最后对PRI研究取得的成果、存在的问题以及发展前景作了总结.

Netprmi ary productivity (NPP) estmi ation is an mi portantstudy field ofglobal change and terrestrial ecosys\ntems(GCTE). Manymodelsused to estmi ateGPP andNPP have been established, such asCASA、Bio-BGC、BEPS、GLO\nPEM, TURC, PSN and so on. Among them, themodelbased on lightuse efficiency (LUE) is very popular in estmi atin\nGPP andNPP at large scale, because itneeds low computation cost, few bio-parameters and easy to be incorporatedwit\nremote sensing data. Therefore, estmi atingLUE accurately is valuable forboth the ecological and global change studies. There have been severalattempts tomodelseasonalvariation ofLUE, mainly as a function ofair temperature, watervapour\npressure deficitand soilwaterdeficit. However, LUE svariationwith environmentalconditions isvery complex, it is inter-\nrupted bymany factors such as air temperature, soilmoisture, plant functional type, disease, nutrition condition, light in-\ntensity, lightcomponent, and so on. The existingmodels are either too smi ple to describe or lack reliability. LUE can be\nestmi ated directly by remote sensing, and itwillbemore desirable. A numberofstudieshave revealed thatphotochemical\nreflectance index (PRI), derived from narrow band reflectance at531 and 570 nm, is relatedwellwithLUE in some con-\nditions, which provides possibility in estmi atingLUE byPRI. Some studieshave confirmed this relationship at leafscale,\ncanopy scale and landscape scale. Meanwhile, many studieshave also found that the relationship between PRI andLUE is\nnot robust enough, which is interrupted seriously bymany disturbances, such as soil background, species composition,\ncanopy structure, sun zenith, view zenith, atmosphere, and so on. Results from smi ulation and expermi entboth revealed\nthat the relationship between PRI and LUE keepswell even under very strict condition, such as high LAI ( leaf area in-\ndex), single specie and so on. Therefore, itstillneedsmore research forwide application ofPRI. Thispaper reviews the\ndefinition ofPRI, physiologicalmechanism leading to the relationship between PRI and LUE, and introduced some case\nstudies to establish the relationship between PRI and LUE through remote sensing. Then some disturbances at leaf scale,\ncanopy scale and landscape scalewere analyzed. In the end, a summary aboutachievements, existing problems and pro-\nspective studies are concluded. Although there are stillmany problems in estmi ation ofLUE through PRI, a few studies\nhave tried to conquer these problems and made some progress. They found that the relationship between PRI and LUE\nwould bemore robustby incorporatingwith other vegetation indices.