Effects Of NPK Fertilizers On Tulip Bulbs Enlargement And Application Research Of Related Genes

As a world famous flower,tulip(Tulipa gesneriana L.)has been continuously applied and cultivated in China in recent years.but due to the limitation of climatic conditions and cultivation techniques,the degradation of tulip bulbs is serious,which restricts the commercial development of tulip in China.It is urgent to improve the cultivation and management technology of tulip.Studies have shown that the imbalance of nutrient supply is one of the reasons for the degradation of tulip bulbs,and nitrogen,phosphorus and potassium are necessary nutrients for plant growth and development,which can achieve the nutrient balance of plants.Therefore,based on the ’ 3414 ’experimental design method,three varieties of tulips were treated with 14 different concentrations of nitrogen,phosphorus and potassium formula fertilization.The growth and development indexes,physiological indexes and integrated quality of tulip bulbs were measured and analyzed,and the best fertilization formula of nitrogen,phosphorus and potassium to promote the expansion of tulip bulbs was selected.At the same time,the function of nitrogen transporter Tg NRT2.5 and phosphorus transporter Tg PHT1.4 was explored.The main results are as follows:1.The application of nitrogen,phosphorus and potassium fertilizers can improve the growth and physiological indexes of tulips to varying degrees.Within a certain range,with the increase of nitrogen and phosphorus fertilizer,the proportion,fresh weight and reproduction coefficient of ‘Veradi’(Ver),‘World’s Favorite’(WF),and ‘Queen of Night’(QN)bulbs with a circumference of 10-12 cm or > 12 cm also increased,which was conducive to the synthesis of nutrients such as starch,sucrose and soluble protein,thus promoting the expansion and development of tulip bulbs.2.The appropriate amount of nitrogen,phosphorus and potassium fertilizer has a significant effect on the integrated quality of tulip bulbs.The membership function method was used to analyze the integrated quality of the sub-balls.It was found that the highest integrated quality of the 14 treatments of the three varieties was T7(N2P3K2)treatment,which was significantly higher than that of T1(N0P0K0)control.Therefore,in order to effectively promote the expansion and development of tulip bulbs,we recommend T7(N2P3K2)treatment,that is,900 mg/L nitrogen fertilizer,450 mg/L phosphorus fertilizer,and 450 mg/L potassium fertilizer.3.Nitrogen transporter gene Tg NRT2.5 responds to low nitrogen stress.Through cloning and expression analysis,it was found that the open reading frame of the gene was1527 bp,encoding 508 amino acids.Under low nitrogen stress,the expression of Tg NRT2.5 in tulip roots was up-regulated.The root length and nitrate nitrogen content of Tg NRT2.5 transgenic Arabidopsis were significantly higher than those of wild-type Arabidopsis,and overexpression of Tg NRT2.5 could promote the expression of nitrogen transport-related genes.4.Phosphorus transporter gene Tg PHT1.4 responds to low phosphorus stress.Through cloning and expression analysis,it was found that the open reading frame of the gene was 1608 bp,encoding 535 amino acids.Under low phosphorus stress,the expression of Tg PHT1.4 in tulip roots was up-regulated.The number of lateral roots and inorganic phosphorus content of Tg PHT1.4 transgenic Arabidopsis were greater than those of wild-type Arabidopsis,and overexpression of Tg PHT1.4 promoted the expression of phosphorus transport-related genes.