荒漠短命植物的养分含量与荧光特征初探

The Nutrient Content of Ephemeral Plants and the Response of Chlorophyll Fluorescence to Light in Desert

摘要: 短命植物作为荒漠植被类群中的独特类型，植物叶片的荧光生理特征和养分含量之间具有极高的相关性。分别选取5种典型短命植物东方旱麦草(Eremopyrum orientale)、卷果涩芥(Malcolmia scorpioides)、狭果鹤虱(Lappula semiglabra)、四齿芥(Tetracme quadricormis)和硬萼软紫草(Arnebiade cumbens)自然生长比较一致的叶片作为研究材料，对叶片的叶绿素和养分含量以及荧光光响应进行了测定。结果表明，短命植物的叶绿素总量为1.24~2.67 mg∙g−1之间，叶绿素a、b含量之比达到5.80~12.86。叶片含N量在3.1%以上，含P量为0.22%~0.30%，含K量在3.15%~6.24%。短命植物的实际光化学量子产量Φ_PSII平均在0.4以上，ETR受光强的抑制不明显，当光合有效辐射值超过1400 mol∙m−2∙s−1时，出现下降。

Abstract: Ephemerals, including annual ephemerals and ephemeroid plants, are characterized by short- term growth rhythms and specific biological traits adapted to deserts or temperate broad-leaved deciduous forests. Their fluorescence physical characteristics had a significant correlation with their leaf contents. The chlorophyll content, nutrient content and response of the photosynthetic characteristics to the simulated light environmental changes of five desert ephemerals, Eremopyrum orientale, Malcolmia scorpioides, Lappula semiglabra, Tetracme quadricormis and Arnebiade cumbens, which distributed in Northwestern China, were investigated. The results showed that the chlorophyll content of ephemerals was between 1.24 and 2.67 mg∙g−1, with extremely high chla/ chlb values reaching 5.80 - 12.86. Ephemerals growing in barren desert had extremely high nutrient use efficiency, with leaf nitrogen content all above 3.1%, leaf phosphorus content between 0.22% and 0.30%, and leaf potassium content between 3.15% and 6.24%. The Φ_PSII of ephemerals on average was above 0.4. The inhibition effect of high light intensity on electron transport rate (ETR) was not obvious, with the latter decreasing only when PAR was above 1400 mol∙m−2∙s−1.