Photosynthetic physiology and growth adaptation of herbages with different photosynthetic pathways in response to drought-rehydration

doi:10.17521/cjpe.2021.0203

Abstract

Abstract:

Aims Based on the background of increasing drought frequency and intensity globally, investigating the photosynthetic properties and growth adaptation of annual grasses differed in photosynthetic pathway (C₃ and C₄) in response to drought-rehydration conditions is useful to predict the changes of grassland ecosystem composition, structure and function in the context of global climate change. Methods The study was conducted as a pot experiment with four annual C₃ and three C₄ grasses widely grown in the Songnen Grassland. Three water levels were set up including control, moderate drought and severe drought. Plant photosynthetic (leaf gas exchange) and growth (biomass, leaf mass per area etc.) parameters were measured at the end of the drought and during the rehydration periods. Important findings The net photosynthetic rate (A) and stomatal conductance (G_s) of all studied species showed a decreasing trend and water use efficiency showed an increasing trend under the drought conditions. There were functional group differences in the effects of drought on photosynthetic properties of the studied plants. The effects of the severe drought on net photosynthetic rate of the C₄ plants are more pronounced than that of the C₃ plants, with the C₄ plants gradually losing their photosynthetic advantage as drought severity increases. The A of the C₄ plants recovered more slowly than that of the C₃ plants after the rehydration because of carbon assimilation in the C₃ plants was mainly restricted by stomata limitation while it in the C₄ plants was mainly restricted by metabolic limitation. The biomass of all studied species decreased, but the root to shoot ratio and leaf mass per area increased, under the drought conditions. The effects of drought on all growth indicators were greater in the C₃ plants than in the C₄ plants. After the rehydration, the biomass of C₃ plants showed a decreasing trend with increasing drought intensity, while the biomass of C₄ plants was not significantly different from the control treatment.

Key words: drought, rehydration, functional group, photosynthetic limitation, root to shoot ratio

Fei LI, Ming-Wei SUN, Shang-Zhi ZHONG, Wen-Zheng SONG, Xiao-Yue ZHONG, Wei SUN. Photosynthetic physiology and growth adaptation of herbages with different photosynthetic pathways in response to drought-rehydration[J]. Chin J Plant Ecol, 2022, 46(1): 74-87.

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https://www.plant-ecology.com/EN/Y2022/V46/I1/74

Figures/Tables 9

References 44

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功能群 Functional group	时期 Period	处理 Treatment	净光合速率 Net photosynthetic rate (μmol·m^-2·s^-1)	气孔导度 Stomatal conductance (mol·m^-2·s^-1)	蒸腾速率 Transpiration rate (mmol·m^-2·s^-1)	水分利用效率 Water use efficiency (μmol·mmol^-1)
C₃	干旱 Drought	对照 CK	13.60 ± 1.13^a	0.51 ± 0.08^a	17.30 ± 1.48^a	0.82 ± 0.07^a
		中度干旱 MD	10.50 ± 1.05^a	0.43 ± 0.08^a	13.30 ± 1.11^b	0.84 ± 0.12^a
		重度干旱 SD	8.13 ± 1.06^b	0.14 ± 0.02^b	6.29 ± 1.03^c	1.48 ± 0.23^b
	复水 Rehydration	对照 CK	15.90 ± 0.44	0.59 ± 0.09	1.12 ± 0.09	0.85 ± 0.27
		中度干旱 MD	15.90 ± 0.51	0.49 ± 0.13	1.44 ± 0.16	0.73 ± 0.27
		重度干旱 SD	15.10 ± 0.16	0.53 ± 0.11	1.12 ± 0.07	0.61 ± 0.24
C₄	干旱 Drought	对照 CK	19.70 ± 2.56^a	0.16 ± 0.01^a	6.90 ± 0.65^a	2.90 ± 0.14
		中度干旱 MD	15.21 ± 0.70^a	0.13 ± 0.01^b	5.13 ± 0.23^a	3.02 ± 0.07
		重度干旱 SD	10.82 ± 0.66^b	0.09 ± 0.02^c	3.53 ± 0.26^b	3.09 ± 0.03
	复水 Rehydration	对照 CK	17.21 ± 0.64	0.14 ± 0.01	4.23 ± 0.12	0.79 ± 0.23
		中度干旱 MD	18.40 ± 1.18	0.14 ± 0.03	4.40 ± 0.98	0.91 ± 0.28
		重度干旱 SD	18.90 ± 1.46	0.16 ± 0.02	3.77 ± 0.57	0.76 ± 0.24

功能群 Functional group	时期 Period	处理 Treatment	净光合速率 Net photosynthetic rate (μmol·m^-2·s^-1)	气孔导度 Stomatal conductance (mol·m^-2·s^-1)	蒸腾速率 Transpiration rate (mmol·m^-2·s^-1)	水分利用效率 Water use efficiency (μmol·mmol^-1)
C₃	干旱 Drought	对照 CK	13.60 ± 1.13^a	0.51 ± 0.08^a	17.30 ± 1.48^a	0.82 ± 0.07^a
		中度干旱 MD	10.50 ± 1.05^a	0.43 ± 0.08^a	13.30 ± 1.11^b	0.84 ± 0.12^a
		重度干旱 SD	8.13 ± 1.06^b	0.14 ± 0.02^b	6.29 ± 1.03^c	1.48 ± 0.23^b
	复水 Rehydration	对照 CK	15.90 ± 0.44	0.59 ± 0.09	1.12 ± 0.09	0.85 ± 0.27
		中度干旱 MD	15.90 ± 0.51	0.49 ± 0.13	1.44 ± 0.16	0.73 ± 0.27
		重度干旱 SD	15.10 ± 0.16	0.53 ± 0.11	1.12 ± 0.07	0.61 ± 0.24
C₄	干旱 Drought	对照 CK	19.70 ± 2.56^a	0.16 ± 0.01^a	6.90 ± 0.65^a	2.90 ± 0.14
		中度干旱 MD	15.21 ± 0.70^a	0.13 ± 0.01^b	5.13 ± 0.23^a	3.02 ± 0.07
		重度干旱 SD	10.82 ± 0.66^b	0.09 ± 0.02^c	3.53 ± 0.26^b	3.09 ± 0.03
	复水 Rehydration	对照 CK	17.21 ± 0.64	0.14 ± 0.01	4.23 ± 0.12	0.79 ± 0.23
		中度干旱 MD	18.40 ± 1.18	0.14 ± 0.03	4.40 ± 0.98	0.91 ± 0.28
		重度干旱 SD	18.90 ± 1.46	0.16 ± 0.02	3.77 ± 0.57	0.76 ± 0.24

功能群 Functional group	物种 Species	处理 Treatment	地上生物量 Aboveground biomass (g·pot^-1)	地下生物量 Underground biomass (g·pot^-1)	总生物量 Total biomass (g·pot^-1)	根冠比 Root to shoot ratio	比叶质量 Specific leaf mass (g·m^-2)
C₃	小黑麦 Triticosecale wittmack	对照 CK	1.38 ± 0.07^a	0.72 ± 0.01^a	2.11 ± 0.14^a	0.61 ± 0.03^c	36.48 ± 0.72^a
		中度干旱 MD	0.97 ± 014^b	0.72 ± 0.05^a	1.60 ± 0.11^b	0.76 ± 0.02^b	42.49 ± 1.70^b
		重度干旱 SD	0.59 ± 0.05^c	0.65 ± 0.02^b	1.21 ± 0.06^b	1.09 ± 0.03^a	50.20 ± 0.71^c
	燕麦 Avena sativa	对照 CK	1.03 ± 0.04^a	0.87 ± 0.01^a	2.03 ± 0.17^a	0.62 ± 0.01^b	24.19 ± 1.96^a
		中度干旱 MD	0.83 ± 0.01^b	0.63 ± 0.05^b	1.53 ± 0.04^b	0.74 ± 0.06^b	28.11 ± 0.40^b
		重度干旱 SD	0.43 ± 0.01^c	0.40 ± 0.01^c	0.84 ± 0.05^c	1.08 ± 0.08^a	36.18 ± 1.75^b
	黑麦草 Lolium perenne	对照 CK	0.80 ± 0.03^a	0.56 ± 0.01^a	1.36 ± 0.04^a	0.65 ± 0.03^c	29.98 ± 0.35^a
		中度干旱 MD	0.61 ± 0.01^b	0.45 ± 0.03^b	1.01 ± 0.05^b	0.73 ± 0.02^b	38.14 ± 0.50^b
		重度干旱 SD	0.41 ± 0.02^c	0.37 ± 0.01^c	0.76 ± 0.03^c	0.86 ± 0.11^a	46.83 ± 1.07^c
	普通小麦 Triticum aestivum	对照 CK	0.84 ± 0.05^a	0.24 ± 0.01^a	0.99 ± 0.03^a	0.20 ± 0.01^c	31.66 ± 1.95^a
		中度干旱 MD	0.65 ± 0.02^b	0.21 ± 0.01^b	0.90 ± 0.03^a	0.36 ± 0.02^b	37.01 ± 1.57^b
		重度干旱 SD	0.40 ± 0.02^c	0.19 ± 0.01^b	0.62 ± 0.01^b	0.52 ± 0.01^a	48.87 ± 1.44^b
C₄	狗尾草 Setaria viridis	对照 CK	2.06 ± 0.09^a	0.99 ± 0.03^ab	3.05 ± 0.11^a	0.47 ± 0.01^b	33.87 ± 1.07
		中度干旱 MD	1.50 ± 0.03^b	1.01 ± 0.09^a	2.45 ± 0.02^b	0.73 ± 0.05^a	37.07 ± 0.07
		重度干旱 SD	1.37 ± 0.04^c	0.94 ± 0.02^b	2.30 ± 0.02^b	0.73 ± 0.01^a	38.93 ± 2.31
	水田稗 Echinochloa oryzoides	对照 CK	1.03 ± 0.02^a	0.64 ± 0.01^a	1.65 ± 0.02^a	0.63 ± 0.01^b	25.14 ± 1.07
		中度干旱 MD	0.83 ± 0.06^b	0.68 ± 0.03^a	1.43 ± 0.07^b	0.74 ± 0.01^a	25.70 ± 0.86
		重度干旱 SD	0.72 ± 0.02^b	0.57 ± 0.01^b	1.27 ± 0.02^c	0.82 ± 0.04^a	25.85 ± 0.71
	虎尾草 Chloris virgata	对照 CK	1.42 ± 0.05^a	0.87 ± 0.11^a	2.33 ± 0.13^a	0.49 ± 0.01^b	34.99 ± 0.72
		中度干旱 MD	1.25 ± 0.03^b	0.62 ± 0.01^b	1.79 ± 0.05^b	0.57 ± 0.02^ab	33.63 ± 0.79
		重度干旱 SD	0.80 ± 0.10^c	0.55 ± 0.03^c	1.34 ± 0.05^c	0.78 ± 0.03^a	33.00 ± 0.97

功能群 Functional group	物种 Species	处理 Treatment	地上生物量 Aboveground biomass (g·pot^-1)	地下生物量 Underground biomass (g·pot^-1)	总生物量 Total biomass (g·pot^-1)	根冠比 Root to shoot ratio	比叶质量 Specific leaf mass (g·m^-2)
C₃	小黑麦 Triticosecale wittmack	对照 CK	1.38 ± 0.07^a	0.72 ± 0.01^a	2.11 ± 0.14^a	0.61 ± 0.03^c	36.48 ± 0.72^a
		中度干旱 MD	0.97 ± 014^b	0.72 ± 0.05^a	1.60 ± 0.11^b	0.76 ± 0.02^b	42.49 ± 1.70^b
		重度干旱 SD	0.59 ± 0.05^c	0.65 ± 0.02^b	1.21 ± 0.06^b	1.09 ± 0.03^a	50.20 ± 0.71^c
	燕麦 Avena sativa	对照 CK	1.03 ± 0.04^a	0.87 ± 0.01^a	2.03 ± 0.17^a	0.62 ± 0.01^b	24.19 ± 1.96^a
		中度干旱 MD	0.83 ± 0.01^b	0.63 ± 0.05^b	1.53 ± 0.04^b	0.74 ± 0.06^b	28.11 ± 0.40^b
		重度干旱 SD	0.43 ± 0.01^c	0.40 ± 0.01^c	0.84 ± 0.05^c	1.08 ± 0.08^a	36.18 ± 1.75^b
	黑麦草 Lolium perenne	对照 CK	0.80 ± 0.03^a	0.56 ± 0.01^a	1.36 ± 0.04^a	0.65 ± 0.03^c	29.98 ± 0.35^a
		中度干旱 MD	0.61 ± 0.01^b	0.45 ± 0.03^b	1.01 ± 0.05^b	0.73 ± 0.02^b	38.14 ± 0.50^b
		重度干旱 SD	0.41 ± 0.02^c	0.37 ± 0.01^c	0.76 ± 0.03^c	0.86 ± 0.11^a	46.83 ± 1.07^c
	普通小麦 Triticum aestivum	对照 CK	0.84 ± 0.05^a	0.24 ± 0.01^a	0.99 ± 0.03^a	0.20 ± 0.01^c	31.66 ± 1.95^a
		中度干旱 MD	0.65 ± 0.02^b	0.21 ± 0.01^b	0.90 ± 0.03^a	0.36 ± 0.02^b	37.01 ± 1.57^b
		重度干旱 SD	0.40 ± 0.02^c	0.19 ± 0.01^b	0.62 ± 0.01^b	0.52 ± 0.01^a	48.87 ± 1.44^b
C₄	狗尾草 Setaria viridis	对照 CK	2.06 ± 0.09^a	0.99 ± 0.03^ab	3.05 ± 0.11^a	0.47 ± 0.01^b	33.87 ± 1.07
		中度干旱 MD	1.50 ± 0.03^b	1.01 ± 0.09^a	2.45 ± 0.02^b	0.73 ± 0.05^a	37.07 ± 0.07
		重度干旱 SD	1.37 ± 0.04^c	0.94 ± 0.02^b	2.30 ± 0.02^b	0.73 ± 0.01^a	38.93 ± 2.31
	水田稗 Echinochloa oryzoides	对照 CK	1.03 ± 0.02^a	0.64 ± 0.01^a	1.65 ± 0.02^a	0.63 ± 0.01^b	25.14 ± 1.07
		中度干旱 MD	0.83 ± 0.06^b	0.68 ± 0.03^a	1.43 ± 0.07^b	0.74 ± 0.01^a	25.70 ± 0.86
		重度干旱 SD	0.72 ± 0.02^b	0.57 ± 0.01^b	1.27 ± 0.02^c	0.82 ± 0.04^a	25.85 ± 0.71
	虎尾草 Chloris virgata	对照 CK	1.42 ± 0.05^a	0.87 ± 0.11^a	2.33 ± 0.13^a	0.49 ± 0.01^b	34.99 ± 0.72
		中度干旱 MD	1.25 ± 0.03^b	0.62 ± 0.01^b	1.79 ± 0.05^b	0.57 ± 0.02^ab	33.63 ± 0.79
		重度干旱 SD	0.80 ± 0.10^c	0.55 ± 0.03^c	1.34 ± 0.05^c	0.78 ± 0.03^a	33.00 ± 0.97

功能群 Functional group	时期 Period	处理 Treatment	地上生物量 Aboveground biomass (g·pot^-1)	地下生物量 Underground biomass (g·pot^-1)	总生物量 Total biomass (g·pot^-1)	根冠比 Root to shoot ratio	比叶质量 Specific leaf mass (g·m^-2)
C₃	干旱 Drought	对照 CK	0.96 ± 0.13^a	0.57 ± 0.13	1.53 ± 0.24^a	0.61 ± 0.11	32.01 ± 2.76^b
		中度干旱 MD	0.73 ± 0.09^a	0.48 ± 0.10	1.21 ± 0.17^a	0.65 ± 0.11	36.40 ± 3.15^b
		重度干旱 SD	0.45 ± 0.05^b	0.38 ± 0.08	0.83 ± 0.12^b	0.86 ± 0.14	45.90 ± 3.48^a
	复水 Rehydration	对照 CK	1.45 ± 0.31^a	0.85 ± 0.27^a	2.31 ± 0.54	0.55 ± 0.11	34.41 ± 2.21
		中度干旱 MD	1.31 ± 0.29^a	0.73 ± 0.27^ab	2.05 ± 0.55	0.53 ± 0.10	34.83 ± 2.13
		重度干旱 SD	1.02 ± 0.24^b	0.61 ± 0.24^b	1.63 ± 0.45	0.56 ± 0.13	32.00 ± 1.91
C₄	干旱 Drought	对照 CK	1.52 ± 0.31	0.84 ± 0.13	2.34 ± 0.44	0.57 ± 0.03	31.70 ± 2.83
		中度干旱 MD	1.24 ± 0.22	0.73 ± 0.12	1.97 ± 0.34	0.61 ± 0.04	31.22 ± 2.83
		重度干旱 SD	0.96 ± 0.18	0.71 ± 0.12	1.67 ± 0.31	0.74 ± 0.03	32.43 ± 3.51
	复水 Rehydration	对照 CK	1.48 ± 0.24	0.79 ± 0.23^ab	2.27 ± 0.47	0.52 ± 0.09	37.81 ± 1.33
		中度干旱 MD	1.64 ± 0.41	0.91 ± 0.28^a	2.55 ± 0.68	0.54 ± 0.07	36.92 ± 1.85
		重度干旱 SD	1.48 ± 0.29	0.76 ± 0.24^b	2.24 ± 0.52	0.52 ± 0.09	35.20 ± 0.85