6种生态型香根草光合光响应特征及光合参数日变化的比较

Comparison Between Six Ecotypes of Vetiver Grasses in Photosynthetic Light Response and Diurnal Variation of Photosynthetic Parameters

为了研究不同生态型香根草(Vetiveria zizanioides)的光合生理差异,比较了Karnataka、Sunshine、Huffman、Kandy、Monto和Veriveria nermorlis这6种生态型香根草的光合光响应特征和光合参数日变化规律。结果表明,除表观量子效率(AQY)外,6种生态型香根草的光饱和点(LSP)、光补偿点(LCP)、最大净光合速率(Pn,max)、暗呼吸速率(Rd)和光合作用日变化均存在明显差异。其中Karnataka和Veriveria nermorlis的LSP、LCP和Pn,max较高;而Sunshine和Kandy的LSP较低,Sunshine和Huffman的LCP较低,Monto的Pn,max最低,Karnataka的Rd较高,而Huffman的Rd较低。Karnataka和Veriveria nermorlis的净光合速率(Pn)日变化呈单峰型,在中午12:00达到最大值;其余4种生态型则呈双峰型,低谷出现在12:00。通过Pn与大气温度(Ta)、大气CO2浓度(Ca)、大气相对湿度(HR)、光照强度(PAR)等生态因子的相关性、通径和决策分析发现,PAR是影响6种生态型香根草Pn日变化的主要决定因子,HR是影响Karnataka、Huffman、Monto和Veriveria nermorlis的Pn日变化的主要限制因子,而Ta是影响Sunshine和Kandy的Pn日变化的主要限制因子。

A study was carried out in order to investigate differences between six ecotypes of vetiver grasses ( Karnataka, Sunshine, Huffman, Kandy, Monto and Veriveria nermorlis) in photosynthetic physiology and rules of diurnal variation of photosynthetic parameters. Results show that the six ecotypes of vetiver grasses varied sharply in light saturation point (LSP), light compensation point (LCP), maximum net photosynthetic rate (Pn,max), dark respiration rate (Rd) and di?urnal variation of net photosynthetic rates ( Pn ) . Among the six ecotypes, Karnataka and Veriveria nermorlis were higher in LSP, LCP and Pn,max; Sunshine and Kandy, lower in LSP; Sunshine and Huffman, lowest in LCP;Monto, lowest in Pn,max;Karnataka, higher in Rd;and Huffman, lower in Rd . Furthermore, the diurnal variations of Pn of Karnataka and Veriveria nermorlis both could be depicted as two single?peak curves with Pn,max appearing at 12:00, while the diurnal var?iations of Pn of the other four ecotypes, as double?peak curves with an obvious midday depression appearing at 12:00. Re?lationships of Pn with ecological factors, such as air temperature ( Ta ) , air CO2 concentration ( Ca ) , relative air humidity (HR) and photosynthetically active radiation (PAR), were analyzed by correlation, path and decision coefficients, re?spectively, indicating that PAR is the primary determining factor for Pn of the six ecotypes of vetiver grasses, HR , the main limiting factor for Pn of Karnataka, Huffman, Monto and Veriveria nermorlis, and Ta the main limiting factor for Pn of Sun?shine and Kandy.