Effects Of Controlled Release Fertilizers On Nutritions,pigments And Spectral Reflectances Of Padus Virginiana 'Schubert'

Studies proved that nutrient release of Controlled Release Fertilizers (CRFs) was accordant with plant uptake of nutrients, contributing to enhancing nutrient use efficiency. But the effects of the CRF on leaf color of ornamental plants were seldom reported. For the leaves becoming purple after green, Padus virginiana'Schubert'was chosen as the test material for studying the anthocyanin synthesis mechanism. With no fertilizer as contorl, making fertilizer treatment before the leaf discoloration. To clear the law of the CRF nutrient release, the experiment researched the law of CRF release in water, then, regarding Padus virginiana'Schubert'as test material, by the pot experiment, studied the effect of CRF on growing development and the physiology and biochemistry index of Padus virginiana'Schubert', and gave a preliminary discussion about spectral reflectances of Padus virginiana'Schubert'on diffenrent fertilizer treatments. Thus , provide theoretical basis for improving its ornamental characteristics by rational fertilization. Main research results were as follows:1. The accumulative nutrient consisting of nitrogen (N) , phosphorous (P) and potassium (K) release curve in static water of compound CRFs showed a similar shape of"S"and can be divided into three stages: slow-releasing period, accelerating-release period and declining period. Nutrient release rate steadily increased with time in the first stage and decreased in the third stage. The nutrients released in the second period reached a summit and satisfied the demanding for nutrients of plants for burgeoning and maturing.2. The effects of the CRF on growth feature of Padus virginiana'Schubert': The CRF promoted the plant height and stem diameter of Padus virginiana'Schubert': Due to releasing slow, the CRF ensured the plants moderate growth in the early day and met the needs of nutrient in the later period. The research of different fertilizing amount showed the plant height and stem diameter of every treatment were the medium treatmentï¹¥the high-amount treatmentï¹¥the low-amount treatment of CRF-A; The research of different fertilizer types showed that the medium treatment of CRF-Aï¹¥the medium treatment of CRF-Bï¹¥the medium treatment of CRF-C. So the treatment of the medium CRF-A had obvious advantages than others.3. The effects of the CRF on leaf color of Padus virginiana'Schubert': The chlorophylls and anthocyanins content of the CRF treatments were significantly higher than the control and CRF crushing treatment. The chlorophylls content of the high-amount treatment of CRF-A was significantly higher than others. And the anthocyanins content of the low-amount treatment of CRF-A was significantly higher than others, the medium treatment of CRF-C taking second place. Therefore, high nitrogen amount made for accumulation of chlorophylls, to the contrary ,low nitrogen, phosphorus amount and right amount potassium made for the anthocyanins synthesis and accumulation.4. The effects of the CRF on the key enzymes of anthocyanins synthesis in Padus virginiana'Schubert'leaves: The CRF after smashing were not good for expressing enzyme activity of PAL, CHI, UFGT, so the result of the CRF treatments was significantly better than crushing treatment. The research of different fertilizing amount showed the DFR and UFGT activity of the medium amount treatment of CRF-A was significantly higher than others, while the low-amount treatment of CRF-A made the PAL and CHI activity higher than others. The research of different fertilizer types showed that the results of CRF-C and CRF-A treatments were better than CRF-B treatment. It was clear that if the nitrogen, phosphorus and potassium in the CRF had a proper ratio and use level, it could make Padus virginiana'Schubert'meeting the vegetative growth , meanwhile , it could make for the accumulation of anthocyanins and make the leaf color bright, increasing its ornamental characteristics.5. It could completely satisfy the nutrient requirement in the discoloration period of Padus virginiana'Schubert'leaves and improve its ornamental value when the CRF was applied one-off. Due to the nutrients lagging release effect, until the end of experiment, all of the total nitrogen, phosphorus and potassium content were higher than the crushing treatment and control treatment. The CRF dosage was not the higher the better because the excessive dosage could cause excess nutrients, reducing the fertilizer utilization. The research showed that the fertilizer utilization of the medium amount treatment of CRF-A and CRF-C was highest, and the nitrogen and potassium utilization was significantly higher than the phosphorus utilization. Therefore, in the discoloration period of Padus virginiana'Schubert', if the right amount CRF that the ratio of nitrogen and potassium was higher was applied, the result was better.6.The spectral features of the leaves appeared significantly change, after the green leaves becoming purple. The reflection peak occurred right shift phenomenon and the reflection reduced. The more anthocyanins content , the right shift of the reflection peak became more significant. Because the reflection peak was located in the red and orange district where there was higher photosynthetic efficiency, it was not good for improving photosynthetic efficiency. Correlation analysis showed that the correlation between spectrum reflection and nitrogen was consistent with the correlation between spectrum reflection and chlorophylls: At visible band 720~760 nm and near infrared 760-800 nm, the correlation between spectrum reflection and nitrogen & chlorophylls content was significant positive. It could be used as sensitive band for monitoring the nitrogen and chlorophylls content in leaves by remote sensing. The correlation between spectrum reflection and anthocyanins content was significant different with the correlation between spectrum reflection and nitrogen & chlorophylls content: At visible band 550~580 nm, the correlation between spectrum reflection and anthocyanins content was significant negativet. It could be used as sensitive band for monitoring the anthocyanins content in leaves of Padus virginiana'Schubert'by remote sensing.