温度对雌雄葎草花芽分化和色素含量及光合作用影响的性别差异

以雌雄异株攀援草本植物葎草为材料,依据野生资源主要分布地域的平均温度,设置3个温度为变量,通过测定营养生长期和生长积温、叶数量与性状、光合色素含量及生物量分配的变化,分析温度对葎草光合物质基础、光合速率和光合效益的影响,研究雌雄株的营养生长持续期、叶性状、光合参数及生物量分配对温度响应的性别差异。结果表明,温度与性别对营养生长持续期和生长积温均有极显著影响(P<0.01),3个温度下雄株花芽分化均显著早于雌株(P<0.05);花芽分化主要受温度影响,生长积温主要受性别影响,20 ℃利于花芽分化,营养生长期长短与积温大小无关;温度对叶性状有显著影响(P<0.05),受影响顺序为叶片数/株>单叶面积>叶宽>叶长,25 ℃时叶片数/株和单叶面积最大;光合色素含量无性别差异(P>0.05),温度显著影响除叶绿素b外的其他色素含量(P<0.05),顺序为类胡萝卜素>叶绿素a+b>叶绿素a/b>叶绿素a>叶绿素b,20 ℃时光合色素含量显著低于其他温度。性别对P_n、G_s和T_r有显著影响(P<0.05),温度对光合参数有显著影响(P<0.05),影响顺序为P_n>C_i>T_r>G_s,P_n、C_i和T_r主要受温度影响,G_s主要受性别影响;雌株生物量及根分配显著大于雄株(P<0.05),温度对生物量累积及分配有极显著影响(P<0.01),随温度下降单株生物量显著下降(P<0.05),温度对生物量分配影响顺序为根>叶>茎,25 ℃时优先向根和茎分配,20 ℃时显著降低了茎分配,15 ℃时显著优先向叶分配。

Effects of temperature on flower bud differentiation,pigment contents,and photosynthesis of male and female Humulus scandens

In this study,we evaluated the effects of temperature on the physiology of male and female plants of the dioecious climbing herb,Humulus scandens.Seeds of H.scandens were sown in pots,and the pots were moved to artificial climate incubators set at 15,20,or 25 ℃ when the seedlings had one to two true leaves.These temperatures were selected based on the average temperatures of the areas where the wild resource are concentrated.We determined the duration of vegetative growth,growth accumulated temperature,number and characteristics of leaves,pigment contents,biomass,and photosynthetic parameters of the male and female seedlings.The effects of temperature on photosynthetic production,net photosynthetic rate (Pn),photosynthetic efficiency,transpiration rate (Tr),intercellular CO2 concentration (Ci),and gas exchange (Gs) were also analyzed.The results showed that,1) temperature and gender had significant effects on growth duration and accumulated temperature (P＜0.01).Flower buds differentiated earlier in male plants than in female plants at all three temperatures (P＜0.05).Flower bud differentiation was affected by temperature and was optimal at 20 ℃.Growth accumulated temperature differed between males and females,but was not related to growth duration.Temperature significantly affected all of the measured leaf traits (P＜0.05),with the strongest effect on leaf number per plant＞＞leaf area per leaf＞＞leaf width＞＞leaf length.The pigment contents did not differ significantly between males and females (P＞＞0.05).Temperature significantly affected the contents of all pigments except for chlorophyll b (P＜0.05) with the strongest effect on carotenoids＞chlorophyll (a+b)＞＞chlorophyll a/b＞＞chlorophyll a＞＞chlorophyll b.Pigment contents were significantly lower at 20 ℃ than at the other temperatures.Photosynthetic parameters differed significantly between males and females and among temperatures (P＜0.05).The temperature affected photosynthetic parameters in the order Pn＞Ci＞Tr＞Gs.The parameters Pn,Ci,and Tr were mainly affected by temperature,but Gs was mainly affected by gender.The biomass and root biomass distribution were significantly higher in female plants than in male plants (P＜0.05).Temperature significantly affected biomass accumulation and allocation in the following order:root＞ leaf＞stem (P＜0.01).Biomass per plant significantly decreased as the temperature decreased (P＜0.05).The highest biomass allocation to the root and stem was at 25 ℃ and the highest biomass allocation to leaves was at 15 ℃.