Effects Of Potassium Levels,Different Plastic Film,Regulated Deficit Irrigation On Growth And Fruit Quality Of Muskmelon

(1)Potassium level in previous nutrient solution for muskmelon varied considerably,which influenced the choose of potassium fertilizer application level.‘Xuelihong‘and‘Flavor No.5‘were selected as the tested materials,the effects of 0,120,240 and 360 mg/L potassium levels on plant growth,net photosynthetic rate,and macroelement accumulation in various organs of muskmelon were studied,in order to optimize potassium fertilizer application in substrate culture.The muskmelon vigorously grew at potassium level of240mg/L in nutrient solution,which was beneficial to photosynthesis,fruit setting.and macroelement accumulation.However,no significant difference in fruit shape index was recorded among the four treatments.The results showed that the sensitivity on potassium levels of‘Xuelihong‘and‘Flavor No.5‘were of differences,the effects of potassium levels on Xue-lihong growth and macroelement accumulation were similar to‘Flavor No.5‘‘s.However,significant difference in net photosynthetic rate were recorded between‘Xuelihong‘and‘Flavor No.5‘.?2?Effects of PO film and PE film on plant growth and fruit quality of muskmelon were investigated.The results showed that the PO film had better light transmittance and heat retai ning property than the PE film.Meanwhile,the growth,fruit soluble solids,soluble sugar,Vit amin C contents,sugar/acid ratio was higher under PO film than those under PE film conditio ns,on the contrary,the organic acids and fruit pulp water contents were lower under PO film t han those under PE film conditions.In conclusion,the PO film than PE film was more efficie nt to the plant growth and fruit quality improvement of muskmelon.?3?Different levels of water deficit was set on different growth stages of melon.That is full irrigation?control group?,low and moderate water deficits irrigation at vine-extending sta ge,low and moderate water deficits irrigation at fruit enlargement stage,total of five treatmen ts.The results showed that muskmelon photosynthetic rate,transpiration rate,intercellular CO₂ concentration and stomatal conductance increased with the increase of water stress decrease d;fruit enlargement stage of light water deficit treatment,made the plant save 5.86%irrigatio n water;its flesh firmness and solid acid ratio also increased by 10.39%and 7.22%;but the yi eld has no significant difference between the control group.Comprehensive analysis,fruit enl argement of light water stress treatment,made it save substantial irrigation without reducing y ield and improve its water use efficiency,the fruit taste and flavor of the melon were excellent than other treatments,this showed that fruit enlargement of light water deficit treatment has a mild positive impact.