Root characteristics of Alhagi sparsifolia seedlings in response to water supplement in the southern fringe of the Taklimakan Desert, Xinjiang
2013-09-29
Water stress is a key factor limiting plant survival and growth, species composition, and community structure in arid areas, and consequently negatively impacts vegetation restoration. Understanding of seedling responses to changes in water availability is essential for the vegetation restoration programs in arid regions.
Perennial shrub species growing in deserts rely on access to water in deep soil layers. Desert shrubs must have deep-reaching roots to tap the soil water at great depths. The root system plays a key role in overcoming water stress and establishing plants in desert areas.
Alhagi sparsifolia Shap. (Leguminosae) is a spiny, perennial subshrub distributed in the foreland of the oases at the southern fringe of the Taklimakan Desert, Xinjiang. As a phreatophyte species, A. sparsifolia has evolved deep roots and is exclusively dependent on groundwater in desert environments. In some regions with deeper groundwater, A. sparsifolia may rely on flooding for successful seedling establishment.
In recent decades, a large area of A. sparsifolia at the southern fringe of the Taklimakan Desert has been seriously damaged due to oasis expansion. Therefore, re-establishment and restoration of plant populations in these regions is crucial. Due to the deterioration of A. sparsifolia and decline of groundwater table in the oasis-desert ecotone at the southern fringe of the Taklimakan Desert, establishment by seeds seems to be more important, and the early growth of A. sparsifolia under water-stressed conditions should be evaluated.
In the Cele oasis, Dr. GUI Dongwei et al. studied the responses of A. sparsifolia seedling roots to water supplement at 10 and 14 weeks under three irrigation treatments (none water supply of 0 m3/m2 (NW), middle water supply of 0.1 m3/m2 (MW), and high water supply of 0.2 m3/m2 (HW)).
The results showed that the variations of soil water content (SWC) significantly influenced the root growth of A. sparsifolia seedlings. The leaf area, basal diameter and crown diameter were significantly higher in the HW treatment than in the other treatments. The biomass, root surface area (RSA), root depth and relative growth rate (RGR) of A. sparsifolia roots were all significantly higher in the NW treatment than in the HW and MW treatments at 10 weeks. However, these root parameters were significantly lower in the NW treatment than in the other treatments at 14 weeks. When SWC continued to decline as the experiment went on (until less than 8% gravimetric SWC), the seedlings still showed drought tolerance through morphological and physiological responses, but root growth suffered serious water stress compared to better water supply treatments. According to our study, keeping a minimum gravimetric SWC of 8% might be important for the growth and establishment of A. sparsifolia during the early growth stage.
These results only enriched the knowledge of responses of woody seedlings to various water availabilities, but also provided a new insight to successfully establish and manage A. sparsifolia in arid environments, further supporting the sustainable development of oases. The study was published in Journal of Arid Land in December 2013.
Perennial shrub species growing in deserts rely on access to water in deep soil layers. Desert shrubs must have deep-reaching roots to tap the soil water at great depths. The root system plays a key role in overcoming water stress and establishing plants in desert areas.
Alhagi sparsifolia Shap. (Leguminosae) is a spiny, perennial subshrub distributed in the foreland of the oases at the southern fringe of the Taklimakan Desert, Xinjiang. As a phreatophyte species, A. sparsifolia has evolved deep roots and is exclusively dependent on groundwater in desert environments. In some regions with deeper groundwater, A. sparsifolia may rely on flooding for successful seedling establishment.
In recent decades, a large area of A. sparsifolia at the southern fringe of the Taklimakan Desert has been seriously damaged due to oasis expansion. Therefore, re-establishment and restoration of plant populations in these regions is crucial. Due to the deterioration of A. sparsifolia and decline of groundwater table in the oasis-desert ecotone at the southern fringe of the Taklimakan Desert, establishment by seeds seems to be more important, and the early growth of A. sparsifolia under water-stressed conditions should be evaluated.
In the Cele oasis, Dr. GUI Dongwei et al. studied the responses of A. sparsifolia seedling roots to water supplement at 10 and 14 weeks under three irrigation treatments (none water supply of 0 m3/m2 (NW), middle water supply of 0.1 m3/m2 (MW), and high water supply of 0.2 m3/m2 (HW)).
The results showed that the variations of soil water content (SWC) significantly influenced the root growth of A. sparsifolia seedlings. The leaf area, basal diameter and crown diameter were significantly higher in the HW treatment than in the other treatments. The biomass, root surface area (RSA), root depth and relative growth rate (RGR) of A. sparsifolia roots were all significantly higher in the NW treatment than in the HW and MW treatments at 10 weeks. However, these root parameters were significantly lower in the NW treatment than in the other treatments at 14 weeks. When SWC continued to decline as the experiment went on (until less than 8% gravimetric SWC), the seedlings still showed drought tolerance through morphological and physiological responses, but root growth suffered serious water stress compared to better water supply treatments. According to our study, keeping a minimum gravimetric SWC of 8% might be important for the growth and establishment of A. sparsifolia during the early growth stage.
These results only enriched the knowledge of responses of woody seedlings to various water availabilities, but also provided a new insight to successfully establish and manage A. sparsifolia in arid environments, further supporting the sustainable development of oases. The study was published in Journal of Arid Land in December 2013.