三峡库区岸边共存松栎树种水分利用策略比较

doi:10.17521/cjpe.2006.0008

摘要/Abstract

摘要：

对三峡库区木鱼岛上马尾松(Pinus massoniana)、槲栎(Quercus aliena)和栓皮栎(Q. variabilis)组成的针阔混交林成林和幼林的光合速率(P_n)、气孔导度(G_s)、清晨和中午水势(ψ_pd和ψ_md)以及叶片稳定碳同位素(δ¹³C)进行了测定。实验结果表明:针叶树马尾松P_n、G_s均低于阔叶树槲栎和栓皮栎(差异达到极显著水平,p<0.001),但马尾松内在水分利用效率(WUE_i, P_n/G_s)却高于槲栎(p=0.003)和栓皮栎(p=0.025)。反映了裸子植物和被子植物木质部不同的水力特性。针阔叶树幼树的P_n和G_s高于成年树,但WUE_i和δ¹³C却低于成年树。表明水分利用效率与水分在树体内传输的距离有关。幼树属于挥霍型水分利用策略,成年树属保守型水分利用策略。三峡大坝的建设所造成的生态环境的改变可能会对三峡库区针阔混交林的演替产生一定的影响,但这需要长期的研究。

关键词: 三峡, 松栎混交林, 水分利用效率, 水势, 稳定碳同位素

Abstract:

With the rise of water level, the construction of the Three-Gorges Dam may have significant impacts on plant carbon-water relation and ecosystem properties in this region. To understand how the plants in this region adapt to the changes in water environments, we measured gas exchange, water potential and δ ¹³C of sapling and mature trees of three co-occurring coniferous and deciduous species: Pinus massoniana, Quercus variabilis and Q. aliena, all are dominant tree species in this region. The two deciduous broad-leaf trees (Q. variabilis and Q. aliena) exhibited higher photosynthetic (P_n) and stomatal conductance (G_s) than the evergreen conifer species (P. massoniana). The predawn water potential (ψ_pd) of P. massoniana was lower than that of the two broad-leaf species. Intrinsic water use efficiency (WUE_i, P_n/G_s) of P. massoniana was higher than those of Q. variabilis and Q. aliena. However, the differences in carbon isotope ratio (δ¹³C) of leaves among species, which gives integrative information of WUE in growing season period, were not statistically significant. We also compared eco-physiological parameters between saplings and mature trees of these three species. The P_n and G_s values of the mature trees were significantly lower than those of the saplings. The mature trees showed lower ψ_pd value, but the difference between the mature trees and the saplings was not statistically significant. However, the WUE_i values of all mature trees were significantly higher than those of the saplings. The δ¹³C values of mature trees showed more positive than those of corresponding saplings, indicating also higher WUE in the mature trees. From these results, we concluded that 1) P. massoniana showed different water use strategies from two Quercus trees species, and 2) the mature trees of these three dominant tree species showed lower photosynthetic rate but higher WUE than those of their corresponding saplings.

Key words: Three Gorges, Pinus-Quercus community, Water use efficiency, Water potential, Carbon isotope ratio

孙双峰, 黄建辉, 林光辉, 韩兴国. 三峡库区岸边共存松栎树种水分利用策略比较. 植物生态学报, 2006, 30(1): 57-63. DOI: 10.17521/cjpe.2006.0008

SUN Shuang-Feng, HUANG Jian-Hui, LIN Guang-Hui, HAN Xing-Guo. CONTRASTING WATER USE STRATEGY OF CO-OCCURRING PINUS-QUERCUS TREES IN THREE GORGES RESERVOIR. Chinese Journal of Plant Ecology, 2006, 30(1): 57-63. DOI: 10.17521/cjpe.2006.0008

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链接本文: https://www.plant-ecology.com/CN/10.17521/cjpe.2006.0008

https://www.plant-ecology.com/CN/Y2006/V30/I1/57

图/表 3

图1 3种植物不同生长阶段的光合速率、气孔导度和内在水分利用效率(平均值±标准误) 大写字母用来表示成年树不同树种间的差异,小写字母表示幼树不同树种间的差异,字母相同表示差异不显著。*表示同一树种成年与幼树间的差异水平(p<0.05)

Fig.1 Photosynthesis, stomatal conductance and intrinsic water use efficiency of mature and sapling of the three species (Means±SE) Different capitals indicate significant difference among mature trees, while different small letters show significant difference among saplings. * indicates the values between the same mature and sapling species is significant (p<0.05)

表1 植物不同生长阶段的清晨水势(ψpd, MPa)和午间水势(ψmd, MPa)

Table 1 Predawn leaf water potential values (ψpd, MPa) (Mean±SE) and midday leaf water potentials (ψmd, MPa) of the three species in different age classes (Mean±SE)

生长阶段 Age class	物种 Species	清晨水势ψ_pd	中午水势ψ_md	ψ_pd-ψ_md
成年树Mature	马尾松Pinus massoniana	-0.39±0.09^A	-1.11±0.10^A	0.72
	槲栎 Quercus aliena	-0.24±0.02^A	-2.34±0.17^B	2.10
	栓皮栎Q. variabilis	-0.23±0.06^A	-2.49±0.18^B	2.25
幼树 Sapling	马尾松Pinus massoniana	-0.31±0.01^a	-0.97±0.08^a	0.67
	槲栎 Quercus aliena	-0.19±0.03^b	-1.52±0.17^b*	1.33
	栓皮栎Q. variabilis	-0.13±0.04^b	-2.66±0.08^c	2.53

图2 3种树木不同生长阶段叶片δP13PC的比较(平均值±标准误) 大写字母用来表示成年树叶片δP13PC值种间差异,小写字母表示幼树种间差异,字母相同表示差异不显著。*表示同一树种成年与幼树间的差异水平(p<0.05)

Fig.2 Foliar δP13PC of mature and saplings of the three species (Mean±SE) Different capitals indicate significant difference among mature trees, while different small letters show significant difference among saplings. * indicates the values between the same mature and sapling species is significant (p<0.05)

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