Study On Selection Of Drought-Resistance Plants And Mulching Technique At Langzhuo Highway In Hebei Province

Selection of drought-resistance plants was studied by means of pot and field test in order to solve greening plants of slope and central green belt in Langzhuo highway in this paper, and clay aggregate mulch how to affect soil temperature, soil water content and plant photosynthesis was analyzed. So this paper would provide a theoretical reference for appropriate plants and mulching technique in Langzhou highway. The main conclusions were as follows:(1)For five candidate plants of central green belt, Euonymus japonicus L and Berberis thumbergii cv.atropurpurea had apparent morphological changes under water stress, Platycladus orientalis Franco and Buxus sinica had small morphological changes under water stress. Euonymus japonicus L had the maximum average changing rate inΨL,Gs, Ci, Pn, Tr, WUE,Fo, Fv,Fv/Fm, Fv/Fo under water stress. Berberis thumbergii cv.atropurpurea had the maximum average changing rate in Fm. Platycladus orientalis Franco had smaller average changing rate in each index. For five candidate plants of slope, Opisthopappus taihangensis had the maximum average changing rate inΨL,Ci, WUE, Fo, Fv/Fm under water stress.Saponaria officinalis Linn had the maximum average changing rate in Pn, Tr,Gs, Fv, Fv/Fo, Sedum spectabile Boreau had smaller average changing rate in each index. The regression equation was established between indices measured and soil water content.(2)According to the direction difference of change of Gs and Ci under water stress, W1 was the boundary of Euonymus japonicus L between stomatal limitation and non-stomatal factors of photosynthesis decreased, and Photosynthetic organs of Euonymus japonicus L was damaged under the condition of W1. W2 were the boundaries of Euonymus japonicus and Berberis thumbergii cv.atropurpurea. W3 were the boundaries of Platycladus orientalis Franco and Rosa chinensis Jacq. W3 were the boundaries of Sedum spectabile Boreau and Iris lactea var. chinensis. W2 were the boundaries of Parthenocissus quinquefolia(L.)Planch, Opisthopappus taihangensis and Saponaria officinalis Linn. WUE of Euonymus japonicus L was the highest in the condition of CK. WUE of Rosa chinensis Jacq, Euonymus japonicus L and Platycladus orientalis Franco were the highest in the condition of W2. WUE of Berberis thumbergii cv.atropurpurea was the highest in the condition of W1. WUE of Sedum spectabile Boreau and Iris lactea var. chinensis were the highest in the condition of W2. WUE of Parthenocissus quinquefolia(L.)Planch, Opisthopappus taihangensis and Saponaria officinalis Linn were the highest in the condition of W1. The lower the soil water content were, the more drough the plants were when WUE of plants were highest. According to the boundaries of Photosynthetic organ damaged and level of soil water content, preliminary judgments could be decided that drought-resistance of Euonymus japonicus L was poor and Platycladus orientalis Franco was good for five candidate plants of central green belt, drought-resistance of Parthenocissus quinquefolia(L.)Planch,Opisthopappus taihangensis and Saponaria officinalis Linn were poor and Sedum spectabile Boreau and Iris lactea var. chinensis were good for five candidate plants of slope.(3) The drought resistance of plants was evaluated by principal component analysis method according to average changing rate of each plant under water stress. The drought resistance order of five candidate plants of central green belt was as follows:Platycladus orientalis Franco>Euonymus japonicus L>Rosa chinensis Jacq>Berberis thumbergii cv.atropurpurea> Euonymus japonicus L. The results of cluster analysis were that Platycladus orientalis Franco, Euonymus japonicus L and Rosa chinensis Jacq were high drought resistance plants, Berberis thumbergii cv.atropurpurea as medium drought resistance plant and Euonymus japonicus L as weak drought resistance plant. The drought resistance order of five candidate plants of slope was as follows:Sedum spectabile Boreau>Iris lactea var. chinensis> Parthenocissus quinquefolia(L.)Planch> Opisthopappus taihangensis> Saponaria officinalis Linn. The results of cluster analysis were that Sedum spectabile Boreau and Iris lactea var. chinensis were high drought resistance plants, Parthenocissus quinquefolia(L.)Planch as medium drought resistance plant, Opisthopappus taihangensis and Saponaria officinalis Linn as weak drought resistance plant.(4)This paper analyzed meteorological data and bare soil water content of Langzhuo highway and found that water was the main limiting factor of plant survival and growth in this area. For five candidate plants of central green belt in field test, the order of WUE daily average presented as: Platycladus orientalis Franco>Euonymus japonicus L>Rosa chinensis Jacq>Berberis thumbergii cv.atropurpurea> Euonymus japonicus L. The order of survival rate presented as:Platycladus orientalis Franco> Euonymus japonicus L> Rosa chinensis Jacq> Berberis thumbergii cv.atropurpurea>Euonymus japonicus L. For five candidate plants of slope in field test, the order of WUE daily average presented as:Sedum spectabile Boreau> Iris lactea var. chinensis> Parthenocissus quinquefolia(L.)Planch>Opisthopappus taihangensis>Saponaria officinalis Linn. The order of survival rate presented as:Sedum spectabile Boreau>Iris lactea var. chinensis> Parthenocissus quinquefolia(L.)Planch>Opisthopappus taihangensis>Saponaria officinalis Linn. The results of field tests consisted with comprehensive evaluation of drought resistance in pots.(5)The effect of clay aggregate mulching on soil temperature decreased with soil depth from Ocm to 15cm. It was obvious that clay aggregate mulching decreased diurnal range of soil temperature but it had less effect on the daily average in summer. clay aggregate mulching had a cooling effect above 5cm,but had a heating effect at 15cm.. M2 balanced soil temperature better than M1. Clay aggregate mulching increased soil water content, reduced soil water content disparity of different soil depth and different months, M2 had better effect than M1.The order of soil water content from 10cm to 60cm depth was as follow:M2>M1>MD. The effect of clay aggregate mulching on soil water content decreased with soil depth.The more months were drought, the more effects of clay aggregate mulching keeping soil water were obvious.(6)Clay aggregate mulching had an impact on Pn, Tr and WUE of Euonymus japonicus L. and Rosa chinensis Jacq. It improve the daily average of Pn and Tr of Euonymus japonicus L. and Rosa chinensis Jacq and made diurnal peak time to change. But clay aggregate mulching had much less impact on WUE than Pn and Tr. M2 had greater impact on photosynthesis than M1. Clay aggregate mulching affected plants growth through affecting plants growth photosynthesis, so clay aggregate mulching greatly improved the survival rates of Euonymus japonicus L, Platycladus orientalis Franco, Rosa chinensis Jacq, Berberis thumbergii cv.atropurpurea and Euonymus japonicus L and increased the growth of diameter at breast and height of five plants. M2 showed better results than M1.(7) According to this researth, I think Platycladus orientalis Franco, Euonymus japonicus L and Rosa chinensis Jacq should be chosen for the central green belt and Sedum spectabile Boreau, Iris lactea var. chinensis and Parthenocissus quinquefolia(L.)Planch should be chosen for the slope in Langzhuo highway. Considering the economic costs, a layer of Clay aggregate mulching (M1) could achieve the desired purpose.