重金属Cr胁迫下两种玉簪光合特性研究

Study on Photosynthetic Characteristics in Two HostaCultivars Under Heavy Metal Cr Stress

以甜心玉簪、紫萼玉簪为试材,采用CIRAS-2型光合仪,研究测定了重金属Cr(0、20、200、400mg/kg)胁迫对甜心玉簪、紫萼玉簪的光合日变化、光响应曲线及叶绿素含量的影响。结果表明:与CK相比,在Cr 20mg/kg胁迫下,叶绿素a、b含量升高、光能利用率和光适应能力最强;在Cr 200mg/kg和Cr 400mg/kg胁迫下,叶绿素a、b含量降低、光响应参数随Cr浓度增加而降低。在各胁迫处理下,2种玉簪净光合速率(Pn)均呈"双峰型"曲线,有明显的光合"午休"现象;净光合速率(Pn)与蒸腾速率(Tr)、气孔导度(Gs)呈正相关,与胞间CO2摩尔分数(Ci)呈负相关。根据不同浓度重金属Cr胁迫下2种玉簪叶绿素和光响应参数与CK比较,甜心玉簪耐重金属能力高于紫萼玉簪。

Hosta×hybrida‘So Sweet＇and Hosta ventricosaas test materials,the CIRAS-type 2photosynthetic apparatus was adopted,with the effects of heavy metal Cr（0,20,200,400mg/kg）stress on Hosta×hybrida‘So Sweet＇and Hosta ventricosa photosynthetic diurnal variation,light response curves and chlorophyll content were studied.The results showed that compared with CK,the content of chlorophyll a and b increased and the solar energy use efficiency and light adaptability were the strongest under the Cr 20mg/kg stress.In the Cr 200mg/kg and Cr 400mg/kg stress,chlorophyll a and b content decreased and light response parameters decreased with the increasing concentration of Cr.In each set of concentration treatment,two kinds of Hostanet photosynthetic rate（Pn）showed the curve of‘double-peak＇typical,had significant midday depression of photosynthesis phenomenon,net photosynthetic rate（Pn）was positively correlated with transpiration rate（Tr）,stomatal conductivity（Gs）.It was negatively correlated with the intercellular CO2concentration（Ci）.According to two kinds of Hostachlorophyll and optical response parameters compared with CK under heavy metal Cr treatment,Hosta×hybrida ‘So Sweet＇ability was higher than Hosta ventricosain heavy metal detoxification and tolerance.