Effects Of Water And Nitrogen Interaction On The Growth,Yield And Quality Of Safflower

This experiment was conducted to investigate the effects of water and nitrogen interaction on agronomic traits,dry matter and nitrogen accumulation,related enzyme activities,quality and yield of safflower(Carthamus tinctorius L.),in order to provide a theoretical basis for high yield and quality of safflower under water nd nitrogen interaction conditions.The experiment was carried out in a dry shed pot with three water levels of W1(35-40%),W2(50-55%)and W3(65-70%)of field water holding capacity and four nitrogen levels of N1(0 kg/hm2),N2(120 kg/hm2),N3(240 kg/hm2)and N4(360 kg/hm2).The main research contents and results are as follows.1.The effects of water-nitrogen interaction on agronomic traits and dry matter accumulation and utilization of safflower were studied.It was found that the height and dry matter mass of safflower plants gradually increased as the reproductive period progressed,the main stem thickness first increased and then decreased,and the center of dry matter accumulation shifted to the buds after the bud emergence.The center of dry matter accumulation shifted to the buds after the bud stage.The height and thickness of the safflower plant gradually increased as the moisture content of the soil increased.The dry matter mass of safflower increases and then decreases with increasing moisture content in the soil at low levels of nitrogen application,and gradually increases under high nitrogen conditions.Under low water conditions,safflower plant height and main stem thickness increased and then decreased with increasing nitrogen application,and dry matter mass gradually increased.Under the W3N2 treatment,the plant height of safflower was 104.68 cm,the main stem thickness of safflower was 8.92 mm under the W2N4 treatment,and the dry matter mass of safflower was 71.93 g/plant under the W3N4 treatment.2.The effect of water-nitrogen interaction on water and nitrogen utilization of safflower was studied.Under the same water treatment,water use and nitrogen harvest index increased gradually with increasing N application,while nitrogen use decreased gradually;under low N conditions,water use and nitrogen harvest index increased and then decreased with increasing water content,while under high N conditions,they increased gradually,but under the same N application treatment,nitrogen use increased gradually with increasing soil moisture content.Nitrogen use increased with increasing soil moisture content.Nitrogen accumulation in safflower plants gradually increased as the fertility period progressed.Nitrogen accumulation in safflower plants gradually increased with increasing N application under the same moisture treatment.Under low water conditions,the application of nitrogen fertilization significantly increased the rate of nitrogen accumulation in safflower plants and increased the amount of nitrogen accumulated by the plants.The maximum nitrogen accumulation in safflower under W3N4 treatment was 1.22 g/plant.Nitrogen accumulation and distribution was similar to that of dry matter.3.The effect of water-nitrogen interaction on the activity of safflower-related enzymes was investigated.Water-nitrogen interaction was found to significantly affect the activity of NR.Under low water conditions,NR activity in leaves gradually increased with increasing nitrogen application,and then increased and then decreased under high water conditions.Under the same N application treatment,NR activity in the leaves increased and then decreased with increasing water content in the soil.As safflower reproduction progressed,the activity of SOD and POD in safflower leaves increased and then decreased,and the content of MDA gradually increased.Both water and nitrogen increase significantly increased the activity of SOD and POD and decreased the content of MDA.The maximum NR activity of the leaves was 7.91 μg/g/h under W2N3 treatment;the maximum SOD and POD activities were 230.11 μ/g and 158.86 μ/g/min respectively under W3N4 treatment,and the minimum MDA content was 3.49 μmol/g.4.The effect of water-nitrogen interaction on safflower yield and quality was investigated.It was found that water-nitrogen interaction significantly affected the yield of safflower,and both Nitrogen fertilization and increased water content significantly increased the yield of safflower seeds and filaments.The maximum yield of safflower seeds and filaments was 24.33 g/plant and 1.73 g/plant respectively under W3N4 treatment,but the difference with W2N4 treatment was not significant.Water-nitrogen interaction had a significant effect on the protein,fat,starch and soluble sugar contents in the seeds.Under low water conditions,protein and fat content increased and then decreased with increased N application,and under high water conditions,protein content increased and then decreased,while fat content continued to increase and then decrease.Under the same water treatment,the soluble sugar content of the seeds gradually increased with increasing N application,while the starch content increased and then decreased.The maximum protein content in the seeds was 20.76% under the W2N4 treatment,and the maximum starch and fat contents were 15.29% and 42.60% respectively under the W3N2 treatment,and 42.60%,however.The maximum percentage soluble sugar content was 3.85% under the W1N4 treatment,but the difference with the W2N4 treatment was not significant.The maximum content of total flavonoids and HYSA in safflower filaments was 2.56% and 3.16%,respectively,under W2N1 treatment,but the difference was not significant between treatments with W3N4.And the content of HYSA in the filaments under all treatments met the requirements of the Chinese Pharmacopoeia.