竹笋期竹箨和笋体的日间蒸腾特性及其对水分运输的影响  

Diurnal transpiration of bamboo culm and sheath and their potential effects on water transport during the bamboo shoot stage

作　　者：李唐吉 王懋林 曹颖[1] 徐刚[1] 杨琪祺 任思源 胡尚连[1,2] LI Tang-Ji;WANG Mao-Lin;CAO Ying;XU Gang;YANG Qi-Qi;REN Si-Yuan;HU Shang-Lian(School of Life Science and Engineering,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China;Engineering Research Center for Biomass Resource Utilization and Modification of Sichuan Province,Mianyang,Sichuan 621010,China)

机构地区：[1]西南科技大学生命科学与工程学院,四川绵阳621010 [2]四川省生物质资源利用与改性工程技术研究中心,四川绵阳621010

出　　处：《植物生态学报》2021年第12期1365-1379,共15页Chinese Journal of Plant Ecology

基　　金：四川省“十四五”重点攻关项目(20zs2172);四川省重点研发项目(2019YFN0005);四川省大学生创新创业训练计划资助项目(19xcy056)。

摘　　要：竹子的高速生长主要发生在无枝无叶的笋期,并对水分需求巨大。水分不仅参与植物体内各种代谢,而且水分转运可促进光合产物、矿质元素、生长激素等物质流动。竹子夜间主要由根压驱动水分转运,但在日间尤其是下午根压基本为负值,明确竹笋日间蒸腾作用发生机制及其对水分运输的影响对竹林培育有重要意义。该研究以不同伸长阶段的慈竹(Bambusa emeiensis)笋为材料,研究了茎秆和竹箨的气孔特征、气孔导度与蒸腾速率等生理特征及在离体条件下竹笋的水分转运速率。结果表明:1)不同发育状态的竹笋茎秆及箨鞘表面均分布有大量气孔,气孔小且凹陷,光合速率及叶绿素a、b含量极低,但气孔导度和蒸腾速率均显著高于成熟叶片,表明笋体和箨鞘是竹笋主要的呼吸和蒸腾部位。2)离体条件下竹笋的番红示踪表明,高生长阶段的竹笋茎秆中番红上升速率较快,有着较强的蒸腾。竹箨分离后,番红仍然能够扩散和运输,表明笋体茎秆也存在一定的蒸腾,但与竹箨包裹的竹笋相比,番红在分离竹箨后的笋体中上升速度显著下降,表明竹箨对笋体内水分运输影响较大。3)箨环处的组织解剖发现,节间的纵向维管束在竹节处特化形成一个类板状结构,弯曲伸入竹箨,是竹箨影响笋体内水分运输的重要结构基础。上述结果表明,日间竹笋水分通过茎秆和竹箨表面的气孔大量蒸散,产生蒸腾拉力驱动笋体内水分转运。该研究也发现,随着茎秆成熟,竹箨松动并开始脱落,茎秆表面的气孔宽度增加,加大了气孔的开口大小,增大了节间气孔与大气水气交换的有效面积,在一定程度上弥补了竹箨脱落时减少的蒸腾拉力。Aims Water transport is of critical impact on the growth of bamboo shoots.The mechanism of diurnal water transpiration by bamboo shoots,and its effect on water transport was not yet fully comprehended.The objectives of this study include:1)to characterize the structure of bamboo shoots that influence transpiration;2)to examine the ability of the structure in transporting water;3)to examine the structure of culm sheath for understanding water transfer in bamboo shoots.Methods Bambusa emeiensis shoots of different elongation stages were used to characterize the stomata,for examining stomatal conductance(G_(s)),transpiration rate(T_(r))and other physiological features of culm sheaths and shoot body.Water transport rate of shoots in vitro was also examined.Important findings The results showed that:1)there are a large number of small and concave stomata on the surface of culm sheath and bamboo shoot of different development states,their net photosynthetic rate(P_(n)),chlorophyll(Chl)a,and Chl b content were extremely low,but G_(s) and T_(r) were significantly higher than that of the mature leaves.These indicated that culm sheath and bamboo shoot play important roles in transpiration and respiration.2)The tracing results of safranine solution in vitro showed that shoots of higher daily elongation rate had stronger transpiration,and were higher rising rate of safranine solution in the bamboo shoots.When culm sheaths of bamboo shoots were separated,the safranine solution could still diffused and transported in the shoot bodies,indicating that the shoot body itself carried some transpiration.However,compared with the intact bamboo shoots wrapped by culm sheaths,the rising safranine solution decreased significantly after the culm sheaths were separated,indicating that the culm sheath could make important contribution for the water transportation.3)Anatomical analysis showed that some longitudinal vascular bundles of the internodes formed a plate-like structure(PLS)at the bamboo nodes,and the ends of PLS gradually bent and

关 键 词：日间蒸腾 水分运输 气孔 竹箨 竹笋 

分 类 号：S795.5[农业科学—林木遗传育种]