Research Of Adaptability Of Three Species Of Plants To Soil Water Potential

In the north cold seasonal frozen soil area, slope protection plants always face the phenomenon that it’s very drought on the top of highway slope but waterlogging at the bottom, therefore, green slope protection plants must have a very strong ability to adapt to the water. At the same time, because of climate and other factors in the northern region, plant species is less, the actual application of the fewer. Amorpha fruticosa L., Lespedeza bicolor Turca and Hippophae rhamnoides L.3kinds of plants as northern common species, have a good adaptability and resistance, and has the certain ornamental value and economic value, have extremely high popularization and application value. At present, a large number of scholars have carried out a detailed study and has a basic clear for physiological response under water stress of Amorpha fruticosa, Lespedeza bicolor and Hippophae rhamnoides. However, in many studies, is just to control the soil moisture of water stress, is only found in3plant internal physiological indicators such as changes in the law, and the results in a real production application is difficult to play a role in. In this paper, we take Amorpha fruticosa, Lespedeza bicolor and Hippophae rhamnoides L.3species as experimental materials, using the laboratory control of soil water potential on plant water stress method, understanding of three kinds of plants under water stress on some physiological indexes of change; through its natural environment of root system architecture in observation, analysis of plant root system distribution in soil by PEG stress state; root analysis three kinds of plant roots to water retention characteristics; after comprehensive analysis of the ability to water of3species plants, ultimately determine the scope for soil water potential. The results show that:(1) the stress of Amorpha fruticosa above-ground parts in≤-0.08Mpa poorer performance on water potential, Lespedeza bicolor in0～-0.02Mpa and≤-0.08Mpa potential is poor, Hippophae rhamnoides in0～-0.02Mpa water potential showed very poor; Amorpha fruticosa underground root with water potential increase, root water potential decreased with fibrous roots developed,, the taproot of Lespedeza bicolor developed, not very remarkable distinction, Hippophae rhamnoides in0～-0.02Mpa water potential, root are very weak, with the lower water potential, root to the horizontal and vertical growth, fibrous root is extremely underdeveloped.(2) three kinds of plants, water saturation deficit, chlorophyll content, soluble sugar, proline content with the water potential is lowered into a rising trend, relative moisture with water potential decreased. Soluble protein, malondialdehyde, cell membrane permeability basically to the-0.02～-0.04Mpa or-0.04～-0.06Mpa water potential as the starting point, to high water and low water potential showed increasing trend. (3) in three species of external form are in-0.02～-0.06Mpa performed best, with soil water potential is increased or decreased exhibit different degrees of symptoms, and physiological index determination results are consistent.(4) Amorpha fruticosa root by vertical growth main root, lateral roots and fibrous roots growth form depth the huge root system can well adapt to various water conditions; Lespedeza bicolor root stout heavy, for the surface soil moisture absorption strong,; Hippophae rhamnoides root is mainly composed of longitudinal and lateral growth of coarse roots constitute frame, lateral root and root stretched root growth, lateral area, is conducive to the drought environment of the plant water.(5) by PEG stress root of measuring the water loss, can determine, in distilled water, Amorpha fruticosa root water retention of the strongest, most of Lespedeza bicolor, Hippophae rhamnoides; in various concentrations of PEG solution, is the strongest Hippophae rhamnoides root water retention, Amorpha fruticosa and Lespedeza bicolor root exhibited similar.(6) comprehensive evaluation analysis can determine, within3months of the water treatment process, Amorpha fruticosa moisture to the widest range, inO～-0.08Mpa water potential within the growth in good condition; Lespedeza bicolor in-0.02～-0.08Mpa potential range can be a good growth of Hippophae rhamnoides in less than-0.02Mpa; the extent of growth good.