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Water is a main controlling factor for economic development and eco-environmental protection in the inland river basins of arid western China. Ground-water, as a component of total water resources, plays a dominant role in the development of western China because of its stable quantity and quality. In recent years, the utilization ratio of surface water has been raised, the ground-water recharge rate from surface water has been reduced, and ground-water has been exploited on a large scale. This has led to the decline of ground-water levels and the degradation of eco-environments. Taking the Heihe river basin as an example, this paper describes ground-water characteristics in the water cycle, deals with the status of ground-water resources, analyses the problems of ground-water resource development and, finally, suggests strategies for rational use of ground-water resources in the arid inland river basins of western China. [Copyright &y& Elsevier]

Ammopiptanthus mongolicus (Maxim.ex Kom.) Cheng f., an ancient relic of the Tertiary Period, is a rare and endangered species of Fabaceae in Mid-Asia desert and has been listed as one of primary protection plants by the Chinese government. Because of its high value of study and ecological usefulness in defending desert, this plant has been called ‘live fossil’. Using the leaves of A. mongolicus derived from water-stressed and water-supplemented environments at Shapotou in the south-east edge of Tengger Desert, seasonal changes of caloric values and osmotica, including free amino acids, total soluble sugar (TSS), sucrose, glucose and inorganic cations have been studied in this paper. The results showed that the main substances involved in osmotic adjustment varied with growth periods and between samples. At the early period it was soluble sugar mainly, and at the late period, besides soluble sugar, potassium and free amino acid (especially proline) also functioned. The higher levels of osmotica content (especially concentrations of total soluble sugar, sucrose, proline and potassium) and caloric values have been found in water-stressed plants rather than in irrigated ones. [Copyright &y& Elsevier]