Study On The Adaptability Of Dalbergia Odorifera To Soils Containing Different Amounts Of Gravels

Legume plant has the huge potential for ecological restoration in the karst rocky desertification areas. Dalbergia odorifera has high anti-adversity ability, developed root and nodules, and it is a new afforestation species with great potential in the ecological restoration. But now, there is still no study about the adaptive mechanism of D. odorifera in karst areas. This study, by researching the effects on morphology, growth and physiology of annual D. Odorifera in the soils containing diiferent amounts of gravels (0%,25%, 50%,75%,100%), aimed at providing basis for the further generalization of D. odorifera in the karst rocky desertification areas(the control group was the soil with 0% gravels content).The results showed that D. odorifera grew better in the soil containing 50% gravels. After 6 and 12 months, its height increased greatest. Compared with the control group’s, the height of D. odorifera in the soils containing 25% and 75% gravels increased greater, but the ground diameter increased significantly smaller.Compared with the control group’s, there was no significant difference of the dry weight of D. Odorifera in the soil containing 50% gravels, but there were significant differences in the soils containing 25%,75% and 100% gravels. With the increasing of gravels content, the dry weight of stem had a decreasing tendency, but the root-shoot ratio had a increasing tendency. In addition,the proportions of the first-order root, the second-order root, the third-order root and the total root all had the increasing tendency.With increasing the gravels content, the soluble sugar and protein contents of D. Odorifera leaves all had the decreasing tendency. Compared with the control group’s, the were no significant differences in the soluble sugar contents of D. Odorifera leaves in the soils containing 25% and 50% gravels, but the soluble protein contents was significantly smaller. There were no significant effects on the POD activity, but with increasing the gravels content, the SOD activity had a increasing tendency.The diumal net photosynthetic rate variation of D. odorifera leaves appeared single peak type. The maximum of the diumal net photosynthetic rate were at 11:00. D. Odorifera had high abilities of potosynthesis in the soils containing 25% and 50% gravels. There were significantly effects on the chlorophyll fluorescence parameters of D. odorifera leaves. With increasing the gravels content, the actual photo-chemical efficiency and the ETR all had the decreasing tendency.D. odorifera is the calciphilous plant. It had a high contents of Ca, Mg and Zn in the soils containing higher gravels, but a low contents of P and K in the soils containing 50% and 75% gravels. With increasing the gravels content, the proportions in the mineral elements of root and leave all had the increasing tendency, but the stem had a decreasing tendency.In the morphology aspect of D. Odorifera, with increasing the gravels content, the stomata had a enlarging tendency. In addition, the surface and volume of the roots were the largest in the soil containing 50% gravels. In the soil containing 100% gravels, the numbers of the nodules were more and the root tips were flatter than the control group’s, the nodules all had a light color and full appearances.In a word, D. odorifera had extremely adaptability of growth and physiology in the soils with different gravels content. The countermeasures of D. odorifera were to add the numbers of nodules,add the proportions of the second-order root and the third-order root,enhance the capability of the potosynthesis, and change the distribution of biomass and mineral elements.