Effects of degradation degree on the root morphological traits and biomass of dominant plant species in alpine meadows

doi:10.17521/cjpe.2024.0019

Abstract

Abstract:

Aims Understanding the adaptive strategies of plant root morphological traits and biomass allocation in alpine meadows under degradation is crucial for exploring the synergistic relationship between root morphological plasticity and biomass distribution. This knowledge is essential for deepening our insight into the stress tolerance strategies of plants in degraded alpine meadows.

Methods In this study, we investigated the aboveground and belowground biomass, root morphological traits, and their interrelationships in grasses (Poa pratensis and Elymus nutans), sedges (Carex alatauensis and C. moorcroftii), and forbs (Anemone rivularis and Saussurea nigrescens) across alpine meadows with varying degrees of degradation (nondegraded, lightly degraded, moderately degraded, and severely degraded).

Important findings The results show that: 1) Carex alatauensis exhibited the greatest reduction in aboveground biomass under moderate degradation (71.44%) while its root-to-shoot ratio increased the most under light degradation (216.92%) among all species examined. Both Poa pratensis and Anemone rivularis showed increased aboveground and belowground biomass under moderate degradation, and their root-to-shoot ratios showed no significant change with increasing degradation. The relative abundance of aboveground biomass in Anemone rivularis and the relative abundance of belowground biomass in Elymus nutans increased the most under severe degradation (384.90% and 299.57%, respectively). 2) Carex alatauensis showed the greatest decrease in total root length under severe degradation (72.81%), whereas Carex moorcroftii had the greatest increase in total root length under light degradation (14.81%). Degradation increased the average root diameter of Poa pratensis, Carex alatauensis, Carex moorcroftii, and Anemone rivularis while recuding their specific root length. The number of root tips and branching in Poa pratensis, Elymus nutans, Carex alatauensis, Anemone rivularis and Saussurea nigrescens decreased as degradation intensified. 3) The relative abundance of Poa pratensis belowground biomass was significantly correlated with the number of root tips. The relative abundance of belowground biomass in both Elymus nutans and Carex alatauensis depended on the total root length and the number of branching. For Carex moorcroftii, the relative abundance of aboveground biomass was mainly correlated with total root surface area, while the relative abundance of belowground biomass depended on root volume and specific root length. The relative abundance of aboveground biomass in both Anemone rivularis and Saussurea nigrescens was significantly associated with total root length, while their relative abundance of belowground biomass was influenced by specific root length. In conclusion, different dominant plant species adapt to the soil microenvironments caused by degradation by adjusting their biomass allocation and root morphological traits, and these adaptive strategies vary among species, reflecting the diversity of stress tolerance strategies in alpine meadow plants.

Key words: alpine meadow, degradation, aboveground biomass, belowground biomass, root morphological traits, dominant species

LIU Wei-Hui, SONG Xiao-Yan, CAIRENDUOJIE , DING Lu-Ming, WANG Chang-Ting. Effects of degradation degree on the root morphological traits and biomass of dominant plant species in alpine meadows[J]. Chin J Plant Ecol, 2024, 48(12): 1666-1682.

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https://www.plant-ecology.com/EN/Y2024/V48/I12/1666

Figures/Tables 8

References 73

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退化梯度 Degradation degree	群落盖度 Coverage (%)	平均高度 Average height (cm)	地上生物量 Aboveground biomass (g·m^-2)	地下生物量 Belowground biomass (g·m^-2)	物种丰富度 Species richness
未退化 ND	0.87 ± 0.01^a	31.00 ± 2.33^a	457.93 ± 68.18^a	519.96 ± 69.59^ab	20.80 ± 0.63^a
轻度退化 LD	0.76 ± 0.01^b	14.17 ± 1.42^b	364.56 ± 93.09^ab	627.41 ± 113.33^ab	19.27 ± 0.50^ab
中度退化 MD	0.65 ± 0.01^c	16.63 ± 4.10^b	206.25 ± 23.78^b	908.18 ± 192.67^a	16.40 ± 0.05^c
重度退化 SD	0.62 ± 0.01^c	3.26 ± 0.24^c	127.04 ± 9.06^b	248.42 ± 35.03^b	17.43 ± 0.73^bc

退化梯度 Degradation degree	群落盖度 Coverage (%)	平均高度 Average height (cm)	地上生物量 Aboveground biomass (g·m^-2)	地下生物量 Belowground biomass (g·m^-2)	物种丰富度 Species richness
未退化 ND	0.87 ± 0.01^a	31.00 ± 2.33^a	457.93 ± 68.18^a	519.96 ± 69.59^ab	20.80 ± 0.63^a
轻度退化 LD	0.76 ± 0.01^b	14.17 ± 1.42^b	364.56 ± 93.09^ab	627.41 ± 113.33^ab	19.27 ± 0.50^ab
中度退化 MD	0.65 ± 0.01^c	16.63 ± 4.10^b	206.25 ± 23.78^b	908.18 ± 192.67^a	16.40 ± 0.05^c
重度退化 SD	0.62 ± 0.01^c	3.26 ± 0.24^c	127.04 ± 9.06^b	248.42 ± 35.03^b	17.43 ± 0.73^bc

退化梯度 Degradation degree	禾本科 Poaceae		莎草科 Cyperaceae		杂类草 Forb
退化梯度 Degradation degree	草地早熟禾 Poa pratensis (%)	垂穗披碱草 Elymus nutans (%)	矮生嵩草 Carex alatauensis (%)	青藏薹草 Carex moorcroftii (%)	草玉梅 Anemone rivularis (%)	钝苞雪莲 Saussurea nigrescens (%)
未退化 ND	20.85 ± 2.89^a	31.00 ± 1.44^a	24.73 ± 1.21^c	61.02 ± 0.71^a	32.63 ± 1.05^ab	26.69 ± 1.79^a
轻度退化 LD	12.45 ± 8.68^ab	21.13 ± 0.27^b	46.96 ± 1.35^b	30.57 ± 0.88^b	34.91 ± 0.73^a	13.26 ± 0.56^b
中度退化 MD	8.90 ± 1.70^b	10.56 ± 1.77^c	58.65 ± 2.61^a	23.68 ± 2.96^b	26.38 ± 1.96^b	25.71 ± 1.67^a
重度退化 SD	14.62 ± 1.68^ab	21.28 ± 3.03^b	46.63 ± 0.87^b	28.04 ± 4.72^b	25.43 ±3.69^b	26.96± 3.19^a

退化梯度 Degradation degree	禾本科 Poaceae		莎草科 Cyperaceae		杂类草 Forb
退化梯度 Degradation degree	草地早熟禾 Poa pratensis (%)	垂穗披碱草 Elymus nutans (%)	矮生嵩草 Carex alatauensis (%)	青藏薹草 Carex moorcroftii (%)	草玉梅 Anemone rivularis (%)	钝苞雪莲 Saussurea nigrescens (%)
未退化 ND	20.85 ± 2.89^a	31.00 ± 1.44^a	24.73 ± 1.21^c	61.02 ± 0.71^a	32.63 ± 1.05^ab	26.69 ± 1.79^a
轻度退化 LD	12.45 ± 8.68^ab	21.13 ± 0.27^b	46.96 ± 1.35^b	30.57 ± 0.88^b	34.91 ± 0.73^a	13.26 ± 0.56^b
中度退化 MD	8.90 ± 1.70^b	10.56 ± 1.77^c	58.65 ± 2.61^a	23.68 ± 2.96^b	26.38 ± 1.96^b	25.71 ± 1.67^a
重度退化 SD	14.62 ± 1.68^ab	21.28 ± 3.03^b	46.63 ± 0.87^b	28.04 ± 4.72^b	25.43 ±3.69^b	26.96± 3.19^a

优势种 Dominant species	最优模型 Optimal model	校正R² Correction R²	p
草地早熟禾 Poa pratensis	RAGB = 0.00006TRL^* - 0.008RV + 0.01RAD - 0.003	0.07	>0.05
垂穗披碱草 Elymus nutans	RAGB = -0.000008TRL^* - 0.02	0.04	>0.05
矮生嵩草 Carex alatauensis	RAGB = 0.0013TRL^*** -0.004	0.03	>0.05
青藏薹草 Carex moorcroftii	RAGB = 0.0004RSA^*** - 0.000003Forks^* - 0.003	0.39	<0.001
草玉梅 Anemone rivularis	RAGB = -0.0004SRL^** + 0.0005TRL^* + 0.01RV^* - 0.003RSA + 0.00003Tips + 0.04	0.34	<0.01
钝苞雪莲 Saussurea nigrescens	RAGB = 0.00005TRL^* + 0.009RAD^* - 1.7344	0.48	<0.001