Responses to Water Stress and a Functional-structural Growth Model of Plant Species Growing in Semi-arid Desertified Areas of Northeast Asia

摘要

The most effective way to combat desertification and restore ecosystems in arid/semi-arid regions is through vegetation rehabilitation. In this study, an accumulation of basic eco-physiological information on plant species was integrated with a functional-structural growth model for selecting the best plant species or species combinations and predicting/assessing the rehabilitation.rnWe examined the growth responses to water stress of 16 plant species growing in arid/semi-arid grasslands in China and Mongolia using environment-controlled growth cabinets. The dry weight growth decreased with increasing water stress in all species, while the degree of depression of the relative growth rate differed among species even of the same life forms such as shrubs, grasses or forbs, and was almost entirely due to the reduction in the net assimilation rate. Some species showed a decrease in their specific leaf area and some showed an increase in their root/shoot ratio, both of which indicated adaptation to fields where water deficiencies occur frequently.rnWe developed an individual-based 3-D plant structure model of several plant species using the Lindenmayer system (L-system) and an object-oriented modeling framework for constructing a "functional-structural plant growth model" based on morphological/eco-physiological characteristics. Plant morphological parameters above/underground were collected in environment-controlled experiments. Stereoscopic individual-based whole plant growth could be simulated, and by comparing plant structures simulated by the program with those of cultivated real plants, the performance of the model could be confirmed to have a potential to simulate 3-D morphological growth of plant species. This model could also simulate the dry weight growth and eco-physiological responses to water stress.