Limits...
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

Biomass allocations (aboveground, leaf meristems, and root biomasses) of Stipa purpurea,Carex moorcroftii,Artemisia nanschanica and the combined community. The different letters indicate biomasses were significantly different between the four blocks (P < 0.05).
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4834318&req=5

ece32059-fig-0003: Biomass allocations (aboveground, leaf meristems, and root biomasses) of Stipa purpurea,Carex moorcroftii,Artemisia nanschanica and the combined community. The different letters indicate biomasses were significantly different between the four blocks (P < 0.05).

Mentions: The grazing block consistently exhibited lower aboveground and root biomasses than the blocks that had been fenced for long durations (F3 and F4) at the species and community levels (P < 0.05; Fig. 3A–D). However, the leaf meristem biomasses of the individual species exhibited different responses to labor management. The S. purpurea in the grazing and short‐term fenced blocks (i.e., the grazing and F1 blocks) exhibited greater leaf meristem biomasses than those in the long‐term fenced blocks (i.e., F3 and F4). However, the C. moorcroftii and A. nanschanica samples from the grazing block exhibited lower leaf meristem biomasses than the samples from F3 and F4 (Fig. 3B, C). Compared to the grazing block, the fenced grasslands exhibited reduced leaf meristem biomasses at the community level (Fig. 3D). The aboveground biomass fractions of the S. purpurea, C. moorcroftii, and community samples were increased, but the leaf meristem biomass percentages were decreased after 1 year of enclosure with a fence (Fig. 4A, B, D). For A. nanschanica, the fractions of leaf meristem biomass in the fenced blocks were higher than that in the grazing block (Fig. 4C). The F3 and F4 blocks always exhibited lower fractions of belowground biomass than the grazing and F1 blocks (Fig. 4A, B, D), with the exception of the A. nanschanica samples (Fig. 4C).


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

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

Biomass allocations (aboveground, leaf meristems, and root biomasses) of Stipa purpurea,Carex moorcroftii,Artemisia nanschanica and the combined community. The different letters indicate biomasses were significantly different between the four blocks (P < 0.05).
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

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

ece32059-fig-0003: Biomass allocations (aboveground, leaf meristems, and root biomasses) of Stipa purpurea,Carex moorcroftii,Artemisia nanschanica and the combined community. The different letters indicate biomasses were significantly different between the four blocks (P < 0.05).
Mentions: The grazing block consistently exhibited lower aboveground and root biomasses than the blocks that had been fenced for long durations (F3 and F4) at the species and community levels (P < 0.05; Fig. 3A–D). However, the leaf meristem biomasses of the individual species exhibited different responses to labor management. The S. purpurea in the grazing and short‐term fenced blocks (i.e., the grazing and F1 blocks) exhibited greater leaf meristem biomasses than those in the long‐term fenced blocks (i.e., F3 and F4). However, the C. moorcroftii and A. nanschanica samples from the grazing block exhibited lower leaf meristem biomasses than the samples from F3 and F4 (Fig. 3B, C). Compared to the grazing block, the fenced grasslands exhibited reduced leaf meristem biomasses at the community level (Fig. 3D). The aboveground biomass fractions of the S. purpurea, C. moorcroftii, and community samples were increased, but the leaf meristem biomass percentages were decreased after 1 year of enclosure with a fence (Fig. 4A, B, D). For A. nanschanica, the fractions of leaf meristem biomass in the fenced blocks were higher than that in the grazing block (Fig. 4C). The F3 and F4 blocks always exhibited lower fractions of belowground biomass than the grazing and F1 blocks (Fig. 4A, B, D), with the exception of the A. nanschanica samples (Fig. 4C).

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