摘要
为了探究冀西北坝上地区白榆的光合生理特性,明确影响白榆光合作用的主要生理生态因子,以白榆(Ulmus pumila)人工纯林为研究对象,利用Li-6400XT便携式光合分析仪测定自然光照条件下白榆叶片的光合生理指标,同时测定气象因子、土壤体积含水率(SWC)及白榆根系的分布,分析各生理生态因子对白榆光合生理指标的影响。结果表明:(1)6:00~18:00,白榆净光合速率(P_(n))、气孔导度(G_(s))、蒸腾速率(T_(r))和气孔限制值(L_(s))日变化趋势呈先上升后下降的“单峰”曲线,胞间CO_(2)浓度(C_(i))日变化趋势呈先下降后上升的“谷型”曲线,水分利用效率(WUE)日变化呈下降趋势。(2)白榆P_(n)的日变化受气孔限制和非气孔限制的共同作用,在8:00~14:00受非气孔限制,其他时段则受气孔限制。(3)白榆P_(n)与G_(ms)、空气湿度(RH)呈极显著正相关关系(P<0.01),与叶片饱和水汽压差(VPD)、100~150 cm SWC呈极显著负相关关系,与0~20 cm SWC呈极显著正相关关系(P<0.05),与40~70 cm SWC呈显著负相关关系。(4)白榆根系在0~200 cm均有分布,但出现浅层化现象,其细根生物量主要集中在0~20 cm土层,粗根主要分布在20~40 cm土层。综上,冀西北坝上地区白榆光合作用日变化主要受G_(s)、RH、SWC的影响,随表层土壤水分变化一致。
In order to explore the photosynthetic physiological characteristics of Ulmus pumila in Bashang area of northwest Hebei Province,the main physiological and ecological factors affecting the photosynthesis of Ulmus pumila were determined.In this study,the artificial pure forest of Ulmus pumila was taken as the research object,and the lI-6400XT portable photosynthesis analyzer was used to measure the photosynthetic physiological indexes of Ulmus pumila leaves under natural light.The meteorological factors were measured in field observation,and the diurnal variation law of soil water content(SWC)was determined by TDR.The effects of physiological and ecological factors on photosynthetic water physiological indexes of Ulmus pumila were analyzed.The results showed that:(1)From 6:00 to 18:00,the diurnal variation trends of net photosynthetic rate(P_(n)),stomatal conductance(G_(s)),transpiration rate(T_(r)),and stomatal limit value(L_(s))of Ulmus pumila presented a"unimodal"curve of increasing first and then decreasing,while the diurnal variation trends of intercellular carbon dioxid(C_(i))presented a"valley-type"curve of decreasing first and then increasing,and the daily variation of water use efficiency(WUE)showed a decreasing trend.(2)The diurnal variation of Ulmus pumila Pn was limited by both stomatal restriction and non-stomatal restriction.Pn was limited by non-stomatal restriction from 8:00 to 14:00 and stomatal restriction at other periods.(3)Pn of Ulmus pumila was positively correlated with G_(s) and air humidity(RH)(P<0.01),and negatively correlated with differential vapor pressure at blade saturation(VPD)and SWC of 100-150 cm.Besides,P_(n) was positively correlated with SWC of 0-20 cm(P<0.05)and negatively correlated with SWC of 40-70 cm.(4)The roots system of Ulmus pumila were distributed in 0-200 cm soil layer,but mainly appeared in shallow layer.The biomass of fine roots was mainly concentrated in 0-20 cm soil layer,and the coarse roots were mainly distributed in 20-40 cm soil layer.In conclusion,the diurnal variation of photosynthesis of Ulmus pumila in Bashang area of northwest Hebei Province is mainly affected by G_(s),RH and SWC,and is consistent with the variation of surface soil water.
作者
魏可新
朱琪
李阳
李晓刚
马增旺
李玉灵
WEI Kexin;ZHU Qi;LI Yang;LI Xiaogang;MA Zengwang;LI Yuling(College of Forestry,Hebei Agricultural University,Baoding 071000,China;Hebei Academy of Forestry and Grassland,Shijiazhuang 050067,China;Fenging National Long-Term Observation and Research Station for Sandy Land Ecosystem of Hebei Province,Fengning 068357,China)
出处
《林业与生态科学》
2025年第2期127-135,共9页
Forestry and Ecological Sciences
基金
河北省省级科技计划资助项目(22326808D)
河北省林草关键技术创新与示范项目(2301085)
河北省林业和草原科技推广示范项目(冀TG〔2022〕016号)。
关键词
白榆
冀西北坝上地区
光合生理特性
环境因子
根系分布
Ulmus pumila
Bashang area of northwest Hebei Province
photosynthetic physiological characteristics
environmental factors
root distribution
