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Desert plant adaptation mechanisms to drought environment, has been the focus of plant stress physiology. Internationally on plant roots - soil interface and its mechanism of hydraulic redistribution quantitative research began in the 20th century, the late 80s, while domestic research in this area is relatively small, in which research on desert plants less. In this paper, the white thorn desert plants (Nitraria sphaerocarpa) for the test material, the use of upper and lower barrel of the root device of the role of white thorn roots for water and their roots for water photosynthesis, root growth and soil available nutrients, mention of root the role of water in the mechanism was discussed; through PEG osmotic stress was studied Nitraria osmoregulation and growth traits in response to drought stress. The main conclusions are as follows: 1, white thorn has a positive, reverse the root to mention the role of water, under the experimental conditions the forward and reverse Hydraulic Lift occurred were 15:00-7:00. Positive mention of water, 815 ± 78g-1695 ± 45g / 3 strains to mention the role of the reverse water liters of water 450 ± 22g-520 ± 34g / 3 strains. Reverse moisture to enhance the effective use of pulsed plant resources (especially precipitation) becomes possible. 2, the role of roots for water and soil water potential occurrence of changes in plant water potential and have a great relationship, a barrel during the test plants root water potential> on the barrel of the soil water potential> leaf water potential, water monitoring to mention root root soil interface water potential difference of 0.54 ± 0.018MPa, when the potential difference reaches 0.97 ± 0.026MPa after no roots for water phenomenon. 3, the role of Hydraulic Lift eased Nitraria water deficit, improve white thorn photosynthetic rate, transpiration rate, stomatal conductance, etc., more conducive to the synthesis and accumulation of photosynthetic products, and enhance the adaptability of white thorn adversity . Hydraulic Lift role in increasing the taproot and lateral roots on the barrel volume, root diameter, and promote the absorption of water and nutrients. 4, the activation of the role of Hydraulic Lift rhizosphere soil nutrients and promotes the absorption of nutrients, the barrel rhizosphere soil mineral nitrogen content increased 32.65% compared with the control, available phosphorus decreased 46.98% compared with the control, no significant differences in potassium. 5, white thorn seedlings in moderate drought conditions may be normal, well-grown, excessive moisture or excessive droughts will adversely affect its growth. Nitraria dry mass concentration increased with PEG first increases and then decreases, 15% of the dry weight of the largest PEG treatment. MDA varies inversely with the amount of dry matter, anti-oxidative stress seedlings Nitraria play a leading role. 6, free proline and soluble sugar is the main Nitraria osmotica. With increasing concentration of PEG, free proline and soluble sugar content was significantly increased; K ~ levels decreased significantly, Na ~ content first and then decreased, but the total cumulative amount remains unchanged.
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