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Leaf meristems: an easily ignored component of the response to human disturbance in alpine grasslands.

Hong J, Ma X, Wang X - Ecol Evol (2016)

Bottom Line: The results revealed that the use of the M b/M a to express the R/S appeared to overestimate the actual value of the R/S, both at species and community levels.The R/S and M b/M a should be cautiously used in combination in the future research.The understanding of the distinction between the R-S and M b-M a may help to improve the biomass allocation mechanism response to human disturbances in an alpine area.

View Article: PubMed Central - PubMed

Affiliation: Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610041China; University of Chinese Academy of SciencesBeijing100049China.

ABSTRACT
Grazing and fencing are two important factors that influence productivity and biomass allocation in alpine grasslands. The relationship between root (R) and shoot (S) biomass and the root:shoot ratio (R/S) are critical parameters for estimating the terrestrial carbon stocks and biomass allocation mechanism responses to human activities. Previous studies have often used the belowground:aboveground biomass ratio (M b/M a) to replace the R/S in alpine ecosystems. However, these studies may have neglected the leaf meristem biomass, which belongs to the shoot but occurs below the soil surface, leading to a significant overestimation of the R/S ratio. We conducted a comparative study to explore the differences between the R/S and M b/M a at both the species (Stipa purpurea, Carex moorcroftii, and Artemisia nanschanica) and community levels on a Tibetan alpine grassland with grazing and fencing management blocks. The results revealed that the use of the M b/M a to express the R/S appeared to overestimate the actual value of the R/S, both at species and community levels. For S. purpurea, the M b/M a was three times higher than the R/S. The M b/M a was approximately two times higher than the R/S for the species of C. moorcroftii and A. nanschanica and at the community level. The relationships between the R-S and M b-M a exhibited different slopes for the alpine plants across all the management practices. Compared to the fenced grasslands, the plants in the grazing blocks not only allocated more biomass to the roots but also to the leaf meristems. The present study highlights the contribution of leaf meristems to the accurate assessment of shoot and belowground biomasses. The R/S and M b/M a should be cautiously used in combination in the future research. The understanding of the distinction between the R-S and M b-M a may help to improve the biomass allocation mechanism response to human disturbances in an alpine area.

No MeSH data available.


Related in: MedlinePlus

Components of the plant biomasses of Stipa purpurea,Carex moorcroftii, and Artemisia nanschanica on a Tibetan alpine grassland.
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ece32059-fig-0001: Components of the plant biomasses of Stipa purpurea,Carex moorcroftii, and Artemisia nanschanica on a Tibetan alpine grassland.

Mentions: All of the individual and community biomass samples were immediately taken to the laboratory and carefully washed. The S. purpurea, C. moorcroftii, and A. nanschanica individuals and community biomass were separated into three parts, including aboveground biomass, leaf meristems and root (Fig. 1). The aboveground biomass and leaf meristems were easily identifiable by color. Because the leaf meristems were situated underground throughout year, they were usually white rather than green (Körner 2003). Morphology and color were the important characteristics to distinguish leaf meristems from root. The individual and community biomasses were oven‐dried at 65°C to a constant weight. The aboveground, leaf meristem and root biomasses were directly weighed with an electronic balance with an accuracy of 0.001 g. The belowground biomass was calculated by adding the root and leaf meristem biomasses, and the shoot biomass was calculated by adding the aboveground and leaf meristem biomasses (Fig. 1). The belowground and shoot biomass fraction (%) was also calculated by the same method. It is worth to note that the community biomass was collected base on the quadrat (g m−2), while the three species (S. purpurea, C. moorcroftii, and A. nanschanica) were collected base on one individual plant (g).


Leaf meristems: an easily ignored component of the response to human disturbance in alpine grasslands.

Hong J, Ma X, Wang X - Ecol Evol (2016)

Components of the plant biomasses of Stipa purpurea,Carex moorcroftii, and Artemisia nanschanica on a Tibetan alpine grassland.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834318&req=5

ece32059-fig-0001: Components of the plant biomasses of Stipa purpurea,Carex moorcroftii, and Artemisia nanschanica on a Tibetan alpine grassland.
Mentions: All of the individual and community biomass samples were immediately taken to the laboratory and carefully washed. The S. purpurea, C. moorcroftii, and A. nanschanica individuals and community biomass were separated into three parts, including aboveground biomass, leaf meristems and root (Fig. 1). The aboveground biomass and leaf meristems were easily identifiable by color. Because the leaf meristems were situated underground throughout year, they were usually white rather than green (Körner 2003). Morphology and color were the important characteristics to distinguish leaf meristems from root. The individual and community biomasses were oven‐dried at 65°C to a constant weight. The aboveground, leaf meristem and root biomasses were directly weighed with an electronic balance with an accuracy of 0.001 g. The belowground biomass was calculated by adding the root and leaf meristem biomasses, and the shoot biomass was calculated by adding the aboveground and leaf meristem biomasses (Fig. 1). The belowground and shoot biomass fraction (%) was also calculated by the same method. It is worth to note that the community biomass was collected base on the quadrat (g m−2), while the three species (S. purpurea, C. moorcroftii, and A. nanschanica) were collected base on one individual plant (g).

Bottom Line: The results revealed that the use of the M b/M a to express the R/S appeared to overestimate the actual value of the R/S, both at species and community levels.The R/S and M b/M a should be cautiously used in combination in the future research.The understanding of the distinction between the R-S and M b-M a may help to improve the biomass allocation mechanism response to human disturbances in an alpine area.

View Article: PubMed Central - PubMed

Affiliation: Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610041China; University of Chinese Academy of SciencesBeijing100049China.

ABSTRACT
Grazing and fencing are two important factors that influence productivity and biomass allocation in alpine grasslands. The relationship between root (R) and shoot (S) biomass and the root:shoot ratio (R/S) are critical parameters for estimating the terrestrial carbon stocks and biomass allocation mechanism responses to human activities. Previous studies have often used the belowground:aboveground biomass ratio (M b/M a) to replace the R/S in alpine ecosystems. However, these studies may have neglected the leaf meristem biomass, which belongs to the shoot but occurs below the soil surface, leading to a significant overestimation of the R/S ratio. We conducted a comparative study to explore the differences between the R/S and M b/M a at both the species (Stipa purpurea, Carex moorcroftii, and Artemisia nanschanica) and community levels on a Tibetan alpine grassland with grazing and fencing management blocks. The results revealed that the use of the M b/M a to express the R/S appeared to overestimate the actual value of the R/S, both at species and community levels. For S. purpurea, the M b/M a was three times higher than the R/S. The M b/M a was approximately two times higher than the R/S for the species of C. moorcroftii and A. nanschanica and at the community level. The relationships between the R-S and M b-M a exhibited different slopes for the alpine plants across all the management practices. Compared to the fenced grasslands, the plants in the grazing blocks not only allocated more biomass to the roots but also to the leaf meristems. The present study highlights the contribution of leaf meristems to the accurate assessment of shoot and belowground biomasses. The R/S and M b/M a should be cautiously used in combination in the future research. The understanding of the distinction between the R-S and M b-M a may help to improve the biomass allocation mechanism response to human disturbances in an alpine area.

No MeSH data available.


Related in: MedlinePlus