植物生态学报 ›› 2021, Vol. 45 ›› Issue (12): 1365-1379.DOI: 10.17521/cjpe.2021.0164

• 研究论文 • 上一篇    下一篇

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

李唐吉1, 王懋林1,2, 曹颖1,*(), 徐刚1, 杨琪祺1, 任思源1, 胡尚连1,2,*()   

  1. 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
  • 收稿日期:2021-04-28 接受日期:2021-07-15 出版日期:2021-12-20 发布日期:2021-09-18
  • 通讯作者: 曹颖,胡尚连
  • 作者简介:Hu SL, hushanglian@126.com
    *Cao Y, caoying@swust.edu.cn;
  • 基金资助:
    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)

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

LI Tang-Ji1, WANG Mao-Lin1,2, CAO Ying1,*(), XU Gang1, YANG Qi-Qi1, REN Si-Yuan1, HU Shang-Lian1,2,*()   

  1. 1School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China
    2Engineering Research Center for Biomass Resource Utilization and Modification of Sichuan Province, Mianyang, Sichuan 621010, China
  • Received:2021-04-28 Accepted:2021-07-15 Online:2021-12-20 Published:2021-09-18
  • Contact: CAO Ying,HU Shang-Lian
  • Supported by:
    14th Five-Year Key Project of Sichuan Province(20zs2172);Key Research and Development Projects of Sichuan Province(2019YFN0005);Sichuan’s Training Program of Innovation and Enterpreneurship for Undergraduate(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。

关键词: 日间蒸腾, 水分运输, 气孔, 竹箨, 竹笋

Abstract:

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 emeiensisshoots of different elongation stages were used to characterize the stomata, for examining stomatal conductance (Gs), transpiration rate (Tr) 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 (Pn), chlorophyll (Chl) a, and Chl b content were extremely low, but Gs and Tr 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 stretched into the bamboo sheath. The PLS may be an important structural basis for water transport of bamboo sheath.

Key words: diurnal transpiration, water transport, stomata, culm sheath, bamboo shoot