蓝、紫粒小麦光合特性的研究

以西南地区的白粒小麦品种("绵阳26"和"川麦107")为对照,对新育成的蓝、紫粒小麦品种(系)在不同发育时期的光合色素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度(Ci)等光合特性进行比较分析。结果表明,蓝、紫粒小麦叶片叶绿素a、叶绿素b和总叶绿素含量和对照的白粒小麦一样,均随孕穗期、抽穗期、开花期、灌浆期和成熟期的发育进程而下降,在孕穗期含量最高,成熟期含量最低;蓝粒小麦的叶绿素a、叶绿素b和总叶绿素含量在各发育时期均最低;白粒小麦的叶绿素a和总叶绿素含量在除孕穗期外的各发育时期最高,成熟期的叶绿素b含量也最高。白粒小麦叶片中类胡萝卜素含量随发育进程一直下降,直至成熟,而紫粒和蓝粒小麦在开花期前逐渐下降,但开花期后又逐渐升高,成熟时达到最大值;灌浆期和成熟期类胡萝卜素含量最高的是蓝粒小麦,其次是紫粒小麦,白粒小麦最低。蓝、紫粒小麦和白粒小麦的净光合速率均随发育进程呈先升后降的变化趋势,开花期净光合速率最大;白粒小麦在除灌浆期外的其他生育期净光合速率最大,蓝粒小麦在开花期后净光合速率是最低的。蓝、紫粒小麦和白粒小麦的气孔导度和蒸腾强度均随发育进程呈单峰曲线变化,峰值出现在灌浆期。白粒小麦的气孔限制值在孕穗期到开花期低于紫粒和蓝粒小麦,而开花期后则高于紫粒和蓝粒小麦。新近育成的几个蓝、紫粒小麦的光合能力低于白粒小麦。

Photosynthetic characteristics of wheat cultivars with blue or purple grain

Changes in photosynthetic pigment content,net photosynthetic rate,stomatal conductance,transpiration rate,intercellular CO_2 concentration and stomatal limitation of blue-or purple-grained wheat cultivars were compared with white-grained wheat cultivars "Mianyang 26" and "Chuanmai 107" to determine photosynthetic characteristics of blue-or purple-grained wheat cultivars.The results show that:(1) The content of chlorophyll a,chlorophyll b and total chlorophyll of all three kinds of wheat cultivars decrease along development stages: booting,heading,flowering,filling and mature.Chlorophyll a,chlorophyll b and total chlorophyll contents of blue-grained wheat are lowest at the five stages;those of chlorophyll a and total chlorophyll of white-grained wheat are highest at each stage,except for booting stage;and chlorophyll b content is also highest at mature stage.Carotenoid content dynamics for purple-and blue-grained wheat cultivars differ from that for white-grained wheat.Carotenoid content decreases along developmental stages in white-grained wheat,but decreases before flowering and then increases thereafter in blue-and purple-grained wheat.At filling and mature stages,carotenoid content is highest in blue-grained wheat,and lowest in white-grained wheat.(2) Net photosynthetic rate of all wheat materials increases at first and then decreases along the five developmental stages,with the highest net photosynthetic rate at flowering stage.Net photosynthetic rate of white-grained wheat is highest among the three kinds of wheat at each developmental stage,except for filling stage,and blue-grained wheat is lowest after flowering.(3) Stomatal conductance and transpiration rate of all the materials appear to have a uni-peak curve,peaking at filling stage.(4) Stomatal limitation in white-grained wheat cultivars is lower than in purple-and blue-grained wheat cultivars from booting to flowering stage,but increases thereafter.It demonstrates that photosynthetic ability of blue-and purple-grained wheat cultivars is lower than that of white-grained wheat cultivars.