不同降水条件下两种荒漠植物的水分利用策略

doi:10.3724/SP.J.1258.2011.00789

摘要/Abstract

摘要：

自然降水是干旱、半干旱地区荒漠植物重要的水分来源。为了说明自然降水量的变化对干旱、半干旱地区荒漠植物水分利用策略的影响, 研究了两种常见荒漠植物油蒿(Artemisia ordosica)和白刺(Nitraria tangutorum)在3个不同自然降水地区(内蒙古的杭锦旗和磴口县及甘肃的民勤县)的水分来源、水分利用效率及植物的抗逆能力的变化。测定了不同地区的植物茎水、各潜在水源(降水、地下水和土壤水)的δD和δ¹⁸O值, 并利用IsoSource模型分析了这两种植物在不同地区对这些潜在水源的选择性利用情况; 同时测定了叶片的δ¹³C和游离脯氨酸浓度。结果表明: 在年降水量最高的杭锦旗, 这两种植物对浅层土壤水的利用比例最高, 其中油蒿主要利用0-50 cm土层中的水源; 在年降水量相对较低的磴口和民勤, 植物利用的主要水源为深层土壤水和地下水。随着年降水量的增加, 这两种植物的水分利用效率逐渐降低。白刺的脯氨酸浓度大于油蒿, 与水分利用效率无关, 但油蒿的水分利用效率和脯氨酸浓度成正比。研究表明, 荒漠植物能通过改变其水分利用策略和其他生理特性适应自然降水量的变化, 但不同植物种采用的策略可能有所不同。

关键词: 干旱、半干旱地区, 油蒿, IsoSource模型, 白刺, 脯氨酸, 稳定同位素, 水分利用效率

Abstract:

Aims In arid and semiarid regions, precipitation is the most important water source for plants. Our objective was to investigate the water-use strategies of two dominant desert plants along a precipitation gradient in northwestern China.

Methods We determined stable hydrogen and oxygen isotope compositions of the stem water from Artemisia ordosicaand Nitraria tangutorum and potential water sources (rain water, groundwater and soil water) at three study sites with different annual precipitation (Hanggin Banner and Dengkou County of Inner Mongolia Autonomous Region and Minqin County of Gansu Province). The IsoSource model was then used to calculate probable contributions of potential water sources to total plant water uptake. We also determined foliar carbon isotope ratios and free proline contents of both species to indicate water use efficiency and osmotic-adjustment ability.

Important findings At the Hanggin Banner site (highest annual precipitation), both species obtained the highest proportion of water from shallow soil water and A. ordosicatook up water mostly from the 0-50 cm soil layer. However, they depended mainly on deep soil water or groundwater at the Dengkou and Minqin sites with lower annual precipitation. The water use efficiency of both species decreased with increasing annual precipitation. There was a positive correlation between carbon isotope ratio and free proline content in A. ordosica. These results suggest that desert plants can adjust their capabilities for up-take from different water sources and other physiological properties with variation in natural precipitation, but the strategies are species-specific.

Key words: arid and semiarid region, Artemisia ordosica, IsoSource model, Nitraria tangutorum, proline, stable isotope, water use efficiency

周雅聃, 陈世苹, 宋维民, 卢琦, 林光辉. 不同降水条件下两种荒漠植物的水分利用策略. 植物生态学报, 2011, 35(8): 789-800. DOI: 10.3724/SP.J.1258.2011.00789

ZHOU Ya-Dan, CHEN Shi-Ping, SONG Wei-Min, LU Qi, LIN Guang-Hui. Water-use strategies of two desert plants along a precipitation gradient in northwestern China. Chinese Journal of Plant Ecology, 2011, 35(8): 789-800. DOI: 10.3724/SP.J.1258.2011.00789

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链接本文: https://www.plant-ecology.com/CN/10.3724/SP.J.1258.2011.00789

https://www.plant-ecology.com/CN/Y2011/V35/I8/789

图/表 9

表1 三个研究样点的概况

Table 1 Major characteristics of three sites

研究点 Study site	经纬度 Latitude and longitude	年平均降水量Annual precipitation (mm)	地下水位Groundwater table (m)	植被类型 Vegetation type	优势种Dominant species	潜在水源的δ¹⁸O δ¹⁸O value of potential water source (‰)		有机碳 Organic C (g·kg^-1)	全N Total N (g·kg^-1)	全P Total P (g·kg^-1)	pH
研究点 Study site	经纬度 Latitude and longitude	年平均降水量Annual precipitation (mm)	地下水位Groundwater table (m)	植被类型 Vegetation type	优势种Dominant species	降水Rain	地下水Groundwater	有机碳 Organic C (g·kg^-1)	全N Total N (g·kg^-1)	全P Total P (g·kg^-1)	pH
甘肃民勤 Minqin, Gansu	38°36′ N, 102°56′ E	113	10-20	灌丛化荒漠 Desert shrub	白刺 Nitraria tangutorum	-4.04	-9.27	1.83 ± 0.07	0.18 ± 0.04		8.93 ± 0.07
内蒙古磴口Dengkou, Inner Mongolia	40°18′ N, 106°56′ E	145	1.5-3.0	灌丛化荒漠 Desert shrub	白刺 Nitraria tangutorum, 油蒿 Artemisia ordosica	-7.60	-9.63	1.58 ± 0.13	0.16 ± 0.02	0.08 ± 0.01	8.67 ± 0.09
内蒙古杭锦旗Hangjin Qi, Inner Mongolia	40°28' N, 108°37' E	258	1.7	灌丛化荒漠Desert shrub	油蒿 Artemisia ordosica	-0.81	-9.64	1.78 ± 0.09	0.13 ± 0.01		8.70 ± 0.21

表2 3个采样地点白刺和油蒿灌丛的形态特征

Table 2 Morphological characteristics of Artemisia ordosica and Nitraria tangutorum in three study sites

		冠幅 Crown diameter (cm)	高 Height (cm)	地径 Diameter at ground height (cm)	根深 Root depth (cm)
白刺 Nitraria tangutorum	民勤 Minqin	323.33 ± 39.10	70.33 ± 7.67	0.89 ± 0.04	>200
	磴口 Dengkou	331.75 ± 3.79	85.28 ± 4.92	0.81 ± 0.05	>200
	杭锦旗 Hanggin Banner	355.67 ± 18.22	120.33 ± 12.91	0.93 ± 0.11	>150
油蒿 Artemisia ordosica	民勤 Minqin	108.00 ± 2.2	89.50 ± 4.99	1.24 ± 0.10	150.00 ± 32.15
	磴口 Dengkou	120.00 ± 6.76	82.25 ± 3.54	1.26 ± 0.17	133.33 ± 36.09
	杭锦旗 Hanggin Banner	129.75 ± 9.75	81.75 ± 5.27	1.22 ± 0.09	88.00 ± 18.90

图1 2009年3个研究样点降水量的分布和取样前雨水的δ18O值。箭头指示的是植物茎样取样时间。

Fig. 1 Precipitation distribution and the δ 18O value of precipitation before sampling in 2009 at three study sites. The arrows indicate the date when plant stem samples were collected.

图2 3个站点植物茎水、雨水和地下水氢氧同位素值的分布特征。直线为全球大气降水线(GMWL) (δD = 8.17 × δ18O + 10.35; Rozanski et al. 1993), 土壤水旁边的标记为土层深度, 雨水旁边的标记为降水日期, 误差线为标准误差 (n = 3)。

Fig. 2 Distribution characteristics of δD and δ 18O values of stem water, rain and groundwater at three study sites. The straight line is global meteoric water line (GMWL) (δD = 8.17 ×δ18O + 10.35; Rozanski et al. 1993). The soil depth was listed next to the symbols for soil water and the date besides the rain symbols indicated the time of each rain event. Error bar represents SE (n = 3).

图3 3个研究样点植物茎水、土壤水、取样前雨水以及地下水的δ18O值。浅灰色阴影指示取样前的雨水氧同位素比值范围, 深灰色阴影指示地下水氧同位素比值范围。误差线为标准误差(n = 3)。

Fig. 3 δ18O of stem water, soil water, rain before sampling and groundwater at three study sites. The light dark shadow bars indicate the ranges of δ 18O for rain water, and the deep dark bars indicate those of groundwater. Error bar represents SE (n = 3).

表3 3个不同研究点油蒿和白刺对各水源的利用比例(%) (平均值(最小值-最大值))

Table 3 Proportions of feasible water sources (%) for Artemisia ordosica and Nitraria tangutorum at three study sites (mean (min-max))

水分来源 Water source		δ¹⁸O‰	民勤Minqin		δ¹⁸O‰	磴口Dengkou		δ¹⁸O‰	杭锦旗Hangjin Qi
水分来源 Water source		δ¹⁸O‰	油蒿 A. ordosica	白刺 N. tangutorum	δ¹⁸O‰	油蒿 A. ordosica	白刺 N. tangutorum	δ¹⁸O‰	油蒿 A. ordosica	白刺 N. tangutorum
土壤深度 Soil depth	0-10 cm	13.6	16.70 (0-50)	1.90 (0-8)	9.90	3.90 (0-16)	0 (0-1)	0.30	40.60 (0-72)	11.60 (0-27)
	10-50 cm	6.1	23.00 (0-75)	3.00 (0-12)	2.20	6.30 (0-25)	0.20 (0-1)	-1.80	37.70 (0-91)	14.50 (0-35)
	50-100 cm	0.7	23.90 (0-89)	4.90 (0-19)	-2.90	10.30 (0-41)	0.60 (0-2)	-8.70	11.40 (0-32)	37.10 (0-82)
	100-150 cm	-1.4	21.60 (0-77)	6.40 (0-25)	-8.50	29.70 (0-97)	2.70 (0-8)
地下水 Groundwater		-9.3	14.90 (0-50)	83.90 (75-92)	-11.50	49.90 (0-84)	96.50 (92-99)	-9.60	10.30 (0-29)	36.80 (0-74)

图4 3个研究样点油蒿和白刺叶片的δ13C值比较(平均值±标准误差, n = 3)。不同大写字母表示差异显著(p < 0.05)。

Fig. 4 Comparison of foliar δ 13C values of Artemisia ordosica and Nitraria tangutorum among three study sites (mean ± SE, n = 3). Different capital letters designate significant difference at p < 0.05.

图5 3个研究样点间两种荒漠植物叶片脯氨酸含量的比较(平均值±标准误差, n = 3)。不同大写字母表示差异显著(p < 0.05)。

Fig. 5 Comparison of foliar proline contents of Artemisia ordosica and Nitraria tangutorum in three study sites (mean ± SE, n = 3). Different capital letters designate significant difference at p < 0.05.

图6 两种荒漠植物叶片δ13C值和脯氨酸浓度的关系。

Fig. 6 Relationship between foliar δ 13C value and proline content in two desert plant species.

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