水分胁迫对油茶容器苗叶片解剖结构和光合特性的影响

Effect of water stress on leaf anatomy structure and photosynthetic characteristic of Camellia oleifera seedlings

【目的】研究油茶容器苗叶片解剖结构和光合生理指标对水分胁迫的响应,了解其水分适应机制,为油茶育苗生产中基质水分的控制提供理论依据。【方法】以"凤阳1号"1年生油茶容器苗为试材,采用盆栽控水方式进行水分胁迫,使基质含水量分别为基质饱和含水量(W)的100%～91%,90%～81%,80%～71%,70%～61%,60%～51%和50%～41%。培养3个多月后,分别测定叶片的气孔特性、光合色素含量和光合生理特性等指标。【结果】随着基质含水量的减少,油茶容器苗的气孔密度、气孔面积、气孔大小和气孔开度发生了明显变化,当基质含水量为(90%～81%)W时,气孔密度和气孔面积均较大,气孔大小和开度均较小。随着基质含水量的减少,叶片、栅栏组织、海绵组织的厚度和栅栏组织/海绵组织都相应减小,光合色素含量和净光合速率、胞间CO2浓度、蒸腾速率、气孔导度和光能利用效率都总体呈下降趋势,但水分利用效率却总体呈上升趋势。当基质含水量为(90%～81%)W时,叶绿素a、叶绿素b、叶绿素a+b、类胡萝卜素含量和叶绿素a/b值均最大。【结论】当基质含水量为饱和含水量的90%～81%时,油茶容器苗木生长最佳。油茶容器苗能在不同水分胁迫下调整叶片结构和光合生理特征以维持正常生存和生长,对水分胁迫具有较强的适应性。

This study aimed to comprehend the adaptability of Camellia oleiferato water stress,and the response mechanism of leaf anatomy structure and photosynthetic characteristic.【Method】＂Fengyang-1＂ seedlings were potted in six water levels（100%-91%,90%-81%,80%-71%,70%61%,60%-51%and 50%-41% to the saturation water content in substrate,respectively） for more than three months.Then stomatic density,stomatic size,stomatic aperture,photosynthetic pigments content and photosynthetic physiological characteristics were determined.【Result】The stomatic density,stomatic area per unit,size and aperture changed as the substrate water content decreased.The stomatic density and area per unit were relative large while the stomatic size and aperture were relative small when the water content of substrate was 90%-81%.The thickness,palisade parenchyma,spongy parenchyma and the ratio of palisade to spongy of leaf declined with the decrease of substrate water content.The photosynthetic pigments content and net photosynthetic rate,intercellular CO 2 density,transpiration rate,stomatal conductance and light use efficiency decreased as the increase of water use efficiency.The chlorophylla,chlorophyllb,chlorophyll a＋b,carotenoid content and chlorophyll a/b reached their highest levels when the substrate water content was 90%-81%.【Conclusion】The C.oleiferaseedlings were in optimal condition when the substrate water content was 90%-81%.Seedlings could adjust the leaf structure and photosynthetic physiological characteristic to maintain their growth based on different water stress,indicating that C.oleifera has strong adaptability to water stress.