The Effect Of SAP On Seed Germination And Seedling Growth Of Caragana Korshinskii Under The Stress Of Cu²⁺, Pb²⁺

With the rapid development of industrialization, heavy metal pollution is becoming increasingly serious. The growth of plants can be affected by heavy metals in the soil. Super absorbent polymers as a polymer material, have good function of water absorption. Besides, the super absorbent polymers can also adsorb heavy metal ions. In this study, the polyacrylamide super absorbent polymers and caragana korshinskii were used as research materials, the interaction between polyacrylamide super absorbent polymers and Cu2+, Pb2+ in Cu(NO3)2,Pb(NO3)2 standard solution was investigated, and the effects of super absorbent polymers on seed germination and growth of caragana korshinskii under the stress of Cu2+, Pb2+ were studied. In order to provide reference for the application of super absorbent polymers on vegetation restoration on the soil which was polluted by heavy metal.The main results of this study are as follows:(1) The water absorbency of super absorbent polymers decreases with the increase of the concentration of Cu2+, Pb2+. There is a significant power function relationship between water absorbency and ion concentration. Ions adsorption amounts increase significantly with the increase of the concentration of Cu2+, Pb2+. The maximum adsorption amounts of Cu2+, Pb2+ are 131.72mg·g-1, 242.68mg·g-1. After the super absorbent polymers are repeated to absorb Cu2+, Pb2+ three times, equilibrium adsorption amounts of Cu2+, Pb2+ are more than seventy five percent of the first equilibrium adsorption amounts.(2) With the increase of Cu2+ concentration, the germination rate, germination energy, germination index of seeds, root length and height of plan seedlings increase firstly and then decrease. While with the increase of Pb2+ concentration, the germination rate, germination energy, germination index of seeds, root length and height of plan seedlings decrease. In other words, low concentration Cu2+ promotes seed germination and seedling growth and high concentration Cu2+ restrains seed germination and seedling growth. While no matter the concentration is low or high, Pb2- shows inhibiting effect of seed germination and seedling growth. In the same concentration, the influence of Pb2- on caragana korshinskii seed germination and seedling growth is more significant than Cu2+. When the super absorbent polymers are used, compared with the control group, the germination rate, germination energy, germination index of seeds, root length and height of plan seedlings all increase. It can be seen that, the super absorbent polymers can promote caragana korshinskii seed germination and seedling growth under the stress of Cu2+, Pb2+.(3) The POD activity and soluble protein content of caragana korshinskii seeds show the similar change regulation, which increases firstly and then decreases with the increase of Cu2+,Pb2+ concentration. When the super absorbent polymers are used under the stress of high concentration Cu2+, Pb2+, the POD activity and soluble protein content of caragana korshinskii seeds are significantly higher than that of control. The super absorbent polymers relieve the damage to POD activity of caragana korshinskii seeds, increase the soluble protein content of caragana korshinskii seeds.(4) With the increase of Cu2+ concentration, the chlorophyll content of caragana korshinskii leaves increases firstly and then decreases. While with the increase of Pb2+ concentration, the chlorophyll content of caragana korshinskii leaves decreases. The proline content and MDA content all increase significantly with the increase of Cu2+, Pb2+ concentration. When the super absorbent polymers are used, the chlorophyll content of caragana korshinskii leaves are higher than the control while the proline content and MDA content lower than control. The super absorbent polymers can alleviate physical stress of Cu2+, Pb2+ on caragana korshinskii leaves.These results indicate that the super absorbent polymers exhibits good adsorption capability to Cu2+, Pb2+, which can alleviate stress of Cu2+, Pb2+on caragana korshinskii seed germination and seedling growth. The super absorbent polymers can be applied to vegetation restoration in the soil polluted by heavy metal.