低钾下光照度与CO_2浓度对不同钾效率基因型甘薯光合作用的影响  

Photosynthesis in response to light intensity and CO_2 concentration under low potassium condition in sweet potato with different genotypes of potassium utilization efficiency

作　　者：唐忠厚[1,2] 陈晓光[1] 魏猛[1] 张爱君[1] 李洪民[1] 丁艳锋[2] 

机构地区：[1]中国农业科学院甘薯研究所/农业部甘薯生物学与遗传育种重点实验室,江苏徐州221121 [2]南京农业大学农学院,江苏南京210095

出　　处：《江苏农业学报》2016年第2期267-273,共7页Jiangsu Journal of Agricultural Sciences

基　　金：江苏省自然科学基金项目(BK20151162);公益性行业(农业)科研专项(201403039;2013030311);江苏科技支撑计划项目(BE2014315)

摘　　要：为揭示不同钾效率基因型甘薯在低钾条件下叶片光合性能及其响应效应,以黄潮土区长期定位试验处理[正常钾处理(NPK处理)和低钾处理(NP处理)]下甘薯为对象,研究低钾条件下不同钾利用效率基因型甘薯光照度与CO_2响应曲线及其特征参数变化。结果显示,2个钾处理下甘薯叶片净光合速率都随光照度的增加迅速上升,当光照度达到1 000μmol/(m^2·s)后渐趋平缓,增大至光饱和点,出现最大净光合速率,光照度达到光饱和点后净光合速率略有下降;NP处理下,胞间CO_2浓度小于200μmol/mol时甘薯叶片净光合速率随胞间CO_2浓度的增加而缓慢升高,200~400μmol/mol时净光合速率随胞间CO_2浓度的增加迅速升高,随后又缓慢升高,直至CO_2饱和点出现最大净光合速率。直角双曲线修正模型拟合分析结果显示,低钾条件下3个不同钾利用效率基因型品种(徐薯18、徐薯32、宁紫薯1号)间最大净光合速率、CO_2补偿点与光补偿点差异显著(P<0.05),饱和光照度与光响应曲线初始斜率差异不显著。与NPK处理相比,NP处理下叶片净光合速率、蒸腾速率、气孔导度与叶绿素含量显著下降,且不同钾利用效率品种间的光合特性存在一定差异。不同钾利用效率品种对光照度与CO_2响应强度次序相同,均表现为:NPK-徐薯18>NPK-徐薯32>NPK-宁紫薯1号>NP-徐薯32>NP-徐薯18>NP-宁紫薯1号。低钾条件下徐薯32叶片有最大净光合速率、饱和光照度与饱和CO_2浓度以及最低CO_2补偿点和光呼吸速率,叶绿素含量受影响小,因此徐薯32较适宜于低钾条件下种植。To understand the photosynthetic performance and light intensity and carbon dioxide（ CO2 ） responses in sweet potato [ Ipomoea batatas （ L.） Lam] genotypes with different potassium utilization efficiencies （ KUE ） , the photosynthetic parameters under low potassium （ K） condition and normal fertilization condition were measured in a long-term located fertilizer experiment＆nbsp;station in Xuzhou. The results showed that the net photosynthetic rate （ Pn ） mounted as light intensity increased, and lev-eled off at light saturation point under both low K level and normal K level. Under low K level, Pn increased slowly as inter-cellular CO2 concentrations（ Ci ） climbed 200 μmol/mol, rose rapidly with Ci of 200-400 μmol/mol, then rose slowly to the peak at Ci saturation point. Three genotypes of sweet potato showed significant differences in maximum net photosynthetic rate, CO2 compensation point and light compensation point, and Pn, transpiration rate（Tr）, stomatal con-ductance（ Gs ） and chlorophyll content index（ CCI） in sweetpotato leaves dropped significantly under low K level. The re-sponses to light intensity and carbon dioxide followed the order of Xushu18〉 Xushu32〉 Ningzishu1 under normal K level〉Xushu32〉 Xushu18〉 Ningzishu1 under low K level. Xushu32 presented maximum photosynthetic rate, the highest saturated CO2 and saturated light intensity, and the lowest CO2 compensation point and photorespiratory rate among varieties under low K level, indicating that Xushu32 is a potential variety for low K planting.

关 键 词：甘薯 低钾 光合作用 光照度 CO2浓度 响应曲线 

分 类 号：S531.01[农业科学—作物学]