鸡冠花品种间耐热性差异的光合生理机制

Photo-physiological mechanisms of tolerant difference to high temperature between two varieties of Celosia cristata

为了研究鸡冠花品种间耐热性差异的光合生理机制,选用耐热品种世纪绿叶"和热敏品种世纪铜叶"进行高温胁迫处理,从气体交换参数、叶绿体各成分含量、叶片对光能的吸收利用及能量分配等方面进行分析.结果表明:高温下生长的世纪绿叶"叶绿素a含量较高,增加了用于光化学的能量,同时非光化学猝灭(NPQ)中状态转换猝灭(qT)的成分较多,能够帮助及时耗散过剩光能,因此没有发生光抑制现象,其净光合速率(Pn)也较高;世纪铜叶"具有较强的耐受高光强能力,但在高温下,其光合作用因非气孔因素导致下降而发生光抑制,这与高温导致其对光能的利用减少,产生了过多的激发能有关,同时,世纪铜叶"叶绿素a含量较少,能态猝灭(qE)和qT含量较小而光抑制和光损伤猝灭(qI)比例较大,不能及时耗散过剩光能,因此对高温敏感.

Photo-physiological mechanisms of tolerant difference to high temperature between two varieties of Celosia cristata,＇Century green＇ and ＇Century copper＇ were investigated.The parameters of gas exchange,chlorophyll content,light energy utilization and distribution were measured.The results showed that,＇Century green＇ had higher chlorophyll a（chla） content,which made more energy distribute to quantum yield of photosystem Ⅱ（ΦPSⅡ）.Meanwhile,higher non-photochemical fluorescence quenching associated with state transitions（qT） in ＇Century green＇ helped to dissipate excessive light energy timely.＇Century copper＇ had a higher tolerance to high light,but photoinhibition happened under high temperature for non-stomatal factors,which reduced light energy utilization.Meanwhile,＇Century copper＇ can not dissipate excessive light energy because of lower chla content and lower proportion of qT.As a result,＇Century copper＇ was more sensitive to high temperature than ＇Century green＇.