Root Spatial Expansion Ability of Leymus chinensis in Response to Clipping and Salt Stress

Publication Type

Contribution to conference

Authors

Liu, J., Gao, Y., Giese, M., Asch, F.

Year of publication

2013

Published in

Agricultural development within the rural-urban continuum

Editor

Tielkes, E.

Pubisher

Cuvillier Verlag , Göttingen

Page (from - to)

423

Conference name

Tropentag 2013

Conference location

Hohenheim

Root system expansion is a complex and important process for rhizomatous plantclonal growth and spatial resource exploration, which is mainly controlled by mor-phological integration. However, experimental evidences are still lacking to under-stand mechanisms for root spatial expansion ability (RSEA) of clonal plants understresses. A 3×3 factorial greenhouse experiment was conducted with a simulatedgrazing gradient (0 %, 35 % and 75 % of shoot removal) under three levels of saline-alkali intensity (0, 100 and 200 mM) to determine the effects of clipping and salt-al-kaline stress on belowground morphological integration ofLeymus chinensis, a highpalatable, dominant grass of the northern chinese steppe ecosystems.Our results showed that plant biomass and relative growth rate were significantly de-creased along the gradient of saline-alkali intensity, but clipping significantly facili-tated plant compensatory growth. The interactions between salt-alkaline and clippingon clonal growth and RSEA were siginificant. Slight saline-alkali stress has positiveimpact on compensatory growth ofL. chinensisat low clipping intensity pressure,resulting in high level of RSEA. But high salt–alkali significantly inhibited clonalgrowth by the limitation of bud outgrowth and rhizome expansion, regardless of clip-ping intensity. Furthermore, when the ranges of the fine root/shoot ratio are from 0.5to 0.6, shoot compensatory growth ofLeymus chinensisis mainly due to the stimu-lation of leaf bud growth; but when this ratio is higher than 0.6,L. chinensisinvestsmore photosynthesate into rhizomes and clonal expansion, and shoot compensatorygrowth originates from the development of rhizome buds into daugther ramets.We conclude that the rhizome grassLeymus chinensisshows a selective biomass al-location strategy under different environmental stress intensities. These plasticitiestranslating into clonal integration are potentially important mechanisms in responseto overgrazing and salt stress and may help to optimise grassland management towardsimproved forage regrowth.