The Research Of Nitrogen, Phosphorus And Potassium Content Of Zoysia Japonica Clonal Ramets And Soil Under Heterogeneous Nutrients

Physiological response mechanism of clonal plant to nutrients has obvious difference compared with the non-clonal plants. The physiological integration between ramets of clonal plants produces great influence on the ecological process of clonal plants and breeding development. The research of the physiological characteristics change between the ramets of clonal plants under heterogeneous nutrient conditions was not only particular, but also had a very important scientific significance and application value.Using zoysiagrass as experimental materials, five treatments were respectively set up when the ramets connected and cut, as the low concentration mather ramet and daughter ramet, the low concentration mather ramet and medium concentration daughter ramet, the low concentration mather ramet and high concentration daughter ramet, the medium concentration mather ramet and low concentration daughter ramet, the high concentration mather ramet and low concentration daughter ramet, each treatment repeated three times. Fertilization treatments were set to high (7.085g NH4NO3,2.063g NaH2PO4 and 2.063g KCL per litre), medium (20% of the high concentration gradient), and low (the same amount of distilled water) concentration gradient. The growth and physiological characteristics of zoysiagrass and the mineral elements contents of the grass and soil were studied under the heterogeneous nutrient. The main results were as follows:1. When the connected mother ramet grew in the medium and high concentration gradient, the increasing extent of the plant height, the ground and underground biomass was smaller than the disconnected mother ramet, but the connected daugher ramet is higher than the disconnected daugher ramet. When mother ramet is under relative high concentration gradient and the daughter ramet under the low concentration, the mother ramet transfered nutrient to the daughter ramet to maintain its normal growth through some physiological integration. When daugher ramet is under relative high concentration gradient and the mother ramet under the low concentration, the plant height, ground and underground biomass had no change compared with the control group. Maybe the physiological integration has directivity.2. The root-shoot ratio of zoysia all declined with different degree, when the connected or disconnected ramets grew in high and medium concentration gradients. This declared that high nutrient may promote the growth of aboveground part in the short term. The chlorophyll content was increased when the connected ramet grew in the high and medium concentration gradient, it declined when ramet was disconnected. When the mother or daugher ramet relatively grew in rich nutrients, but the connected daughter or mother ramet grew in poor nutrients, there may be existed some kind of physiological integration between them. Leaf area index of connected and disconnected increase under high concentration gradient, and it was no different under the medium and low concentration gradient.3. The increase range of the ammonium nitrogen of the connected mother ramet was smaller than the disconnected one, but the connected daughter ramet was higher than the disconnected. The mother ramet under high concentration gradient occurred physiological integration with the daughter ramet under low concentration gradient. The nitrate of ramets under high and medium concentration gradient was reduced, because the zoysiagrass absorbed nitrate, and then changed into other nitrogenous organic matter. The total nitrogen of the connected and disconnected ramet and soil, under high concentration gradient was increased, and it showed no difference between the medium and low concentration gradient.4. The total phosphorus of connected and disconnected ramet under medium concentration gradient all declined in some extent, the total phosphorus under the high concentration gradient showed no difference with low concentration. The reason is that the mobility of phosphorus is weak, and its utilized efficiency decreased. The total soil phosphorus under medium concentration gradient was lower than that under control, and the total soil phosphorus under high concentration gradient was higher than that under control. It may be that the rhizosphere pH value affected the determination of the effectiveness of phosphorus.5. The total potassium the connected mother ramet under high and medium concentration gradient increased, and was smaller than the disconnected one. That value of the connected daughter ramet was higher than the disconnected. When the mother ramet was under high concentration and the daughter was under low concentration, the mother ramet could transfer nutrient to the daughter ramet by physiological integration to maintain its normal growth. The total soil potassium under high and medium concentration gradient was same to the control group, because the potassium in the soil was on homogeneous state.