植物生态学报 ›› 2014, Vol. 38 ›› Issue (6): 562-575.doi: 10.3724/SP.J.1258.2014.00052

所属专题: 稳定同位素生态学

• 研究论文 • 上一篇    下一篇

青藏高原20种灌木抗旱形态和生理特征

邱权1*, 潘昕1, 李吉跃1**, 王军辉2**, 马建伟3, 杜坤3   

  1. 1华南农业大学林学院, 广州 510642;
    2中国林业科学研究院林业研究所, 国家林业局林木培育重点实验室, 北京 100091;
    3甘肃省小陇山林业科学研究所, 甘肃天水 741022
  • 收稿日期:2013-07-16 修回日期:2014-03-12 出版日期:2014-06-01 发布日期:2014-06-10
  • 通讯作者: 李吉跃 E-mail:ljyymy@vip.sina.com
  • 基金资助:

    林业公益性行业科研专项;农业科技成果转化资金项目

Morphological traits and physiological characteristics in drought tolerance in 20 shrub species on the Qinghai-Xizang Plateau

QIU Quan1*, PAN Xin1, LI Ji-Yue1**, WANG Jun-Hui2**, MA Jian-Wei3, and DU Kun3   

  1. 1College of Forestry, South China Agricultural University, Guangzhou 510642, China;

    2Research Institute of Forestry, Chinese Academy of Forestry, Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Beijing 100091, China;

    3Xiaolongshan Forestry Science and Technology Research Institute, Tianshui, Gansu 741022, China
  • Received:2013-07-16 Revised:2014-03-12 Online:2014-06-01 Published:2014-06-10
  • Contact: LI Ji-Yue E-mail:ljyymy@vip.sina.com

摘要:

该研究以青藏高原地区采集的柠条锦鸡儿(Caragana korshinskii)等20种灌木树种为研究对象, 将其二年生幼苗移栽至苗圃培育, 通过田间试验测定三年生苗木生物量根冠比(RSR)、叶片蒸腾速率(Tr)、瞬时水分利用效率(WUEi)、稳定碳同位素组成(δ13C)、叶片解剖结构特征和根系特征(长度、表面积、体积和根尖数)指标, 综合分析其抗旱性能差异, 为青藏高原干旱地区灌木树种抗逆性(耐旱)评价指标的建立、优良抗逆性树种的筛选及各种灌木树种的合理立地配置提供必要的理论依据。研究结果表明: 所选20种灌木为适应长期的干旱逆境, 不同植物种具有不同的抗旱策略。研究中将灌木抗旱机制划分为6个类型: 根系特征抗旱型、叶片旱生结构型、叶片旱生形态型、生物量分配型、节水型、高水分利用效率型。不同属和同属不同种灌木抗旱性有所差异, 沙棘属(Hippophae)植物总体抗旱性不佳, 而金露梅(Potentilla fruticosa)、豪猪刺(Berberis julianae)、树锦鸡儿(Caragana arborescens)、绣线菊(Spiraea salicifolia)和蒙古沙棘(Hippophae rhamnoides ssp. mongolica)综合抗旱性能较好, 总体上属于根系和叶片抗旱特征明显、低耗水、高生产效率的抗旱性强树种, 可以在青藏高原地区植被恢复树种筛选时优先考虑。根系特征值之间存在极显著正相关关系, 叶片结构特征指标之间也存在不同程度的相关关系, 但RSRTrWUEiδ13C与根系特征值和叶片解剖结构特征指标之间总体上相关性不显著。主成分分析结果显示灌木全根和细根的长度、表面积、体积、根尖数和叶片栅栏组织厚度、海绵组织厚度、瞬时水分利用效率因子载荷较高, 能较好地反映青藏高原灌木树种抗旱性差异相关信息。此外, 灌木树种原产地与抗旱性也存在一定的联系, 青海西宁地区采集的灌木树种总体抗旱性优于甘肃天水和西藏拉萨地区。

Abstract:
Aims Providing indispensably theoretical evidence for establishing indices of evaluation on drought tolerance in shrubs, and screening for tree species that are drought tolerant for afforestation in arid regions or for matching their characteristics with suitable habitat conditions are the key to vegetation restoration in the Qinghai-Xizang Plateau. However, these issues are not adequately addressed in recent research due to lack of systematic methods. Therefore, our objective was to make a comprehensive evaluation on drought tolerance in 20 shrub species collected from different areas in Qinghai-Xizang Plateau, and to study their underlying mechanisms in drought tolerance.
Methods We made measurements on variables depicting root characteristics, including the root length (TRL), surface area (TRSA), volume (TRV), and tips number (TRTN) of all roots, the root length (FRL), surface area (FRSA), volume (FRV), and tips number (FRTN) of fine roots (d ≤2 mm), and derived plant characteristic indices including thickness of cuticle (CT), thickness of palisade tissue (TPT), thickness of spongy tissue (TST), TPT/TST, thickness of leaf (LT), palisable tissue cell density, and tissue structural tense ratio (CTR = TPT/LT × 100%) and spongy tissue loosened ratio (SR = TST/LT × 100%) of leaf anatomical structure, root to shoot ratio (RSR), leaf transpiration rate (Tr), instantaneous water use efficiency (WUEi), and carbon isotopic composition (δ13C) of the 20 shrub species through field experiments. Correlation analysis and principal component analysis were performed on the 19 variables and indices.
Important findings Different shrubs had different mechanisms of drought tolerance. In this study, the characteristics of drought tolerance were mainly categorized into 6 types, involving modifications of (1) root systems, (2) leaf anatomical structure, (3) leaf pattern, and (4) biomass allocation, or via (5) low water-consumption and (6) high WUEi. Different genera or different tree species within the same genus clearly differed in drought tolerance. The species of the genus Hippophae were relatively poorly tolerant to drought, whereas several shrubs including Potentilla fruticosa, Berberis julianae, Caragana arborescens, Spiraea salicifolia and Hippophae rhamnoides ssp. mongolica occurred to be more drought tolerant than other shrub species investigated in this study. On the other hand, there were highly significant correlations among the characteristics of root systems and among characteristics of leaf anatomical structure. The results of principal component analysis on 19 variables and indices showed that TRL, TRSA, TRV, TRTN, FRL, FRSA, FRV, FRTN, CT, TPT, TST and WUEi could be effective indicators of drought tolerance of shrubs in the Qinghai-Xizang Plateau. In addition, the drought tolerance of shrubs had a close connection with their origin of collections; the shrubs collected from Xining prefecture in Qinghai Province were more drought tolerant than those from Tianshui Prefecture in Gansu and Lasa Prefecture in Xizang.