Effects Of NPK On The Vegetative Growth And Physiological Characteristics Of Agapanthus Under Hydroponics Conditions

In this paper,effects of different nitrogen(N),phosphorus(P),potassium(K) levels,N forms, consistency and water quality on Agapanthus praeco ssp.orientalis 'Big Blue' were studied adopting the meaning of hydroponics.Plant materials were biennial seedling plant.The results can be summarized as followed:(1)Effects of different N,P,K levels on plants were studied through orthogonal experiment,the results indicated optimal combinatory:the concentration of N,P,K were 210mg/L(N2),31mg/L(P1),234mg/L(K3) separately,that is to say N:P:K=6.77:1:7.55.Under hydroponics conditions,within the concentration of this experiment,suitable concentration of N was beneficial to growth,but excess is to inhibit the growth;low-level P is suitable to aerial growth,increasing P can hasten the growing development of roots;high-level K was beneficial to the vegetable growth of Agapanthus praeco ssp.orientalis 'Big Blue'.When N level was 210mg/L(N2),the growth performance was the best,various indexes were better than 112mg/L(N1),308mg/L(N3),compared with N1,N3,dry weight of the plant increased by 85.71%,26.17%;the activity of roots was up to 35.267μgTPF·g^-1·FW·h^-1,significant higher than N3,but there were no significant difference compared with N1.P,K level were 31mg/L(P1),234mg/L(K3),the plant grew best and dry weight was biggest.(2)The experiment of different N forms proportions indicated:NH₄⁺-N and NO₃^--N were applied in this experiment together,the growth station of plants were worse when NH₄⁺-N:NO₃^--N was 5:95,and a few plants were died;other treatments,that is to say,NH₄⁺-N:NO₃^--N was 10:90,25:75,50:50,75:25,they were all well-grown.NH₄⁺-N:NO₃^--N was 10:90 is optimal,all indexes were better than the others,dry biomass of the plant was 2.793g. Compared with other treatments,it showed significant difference,activity of roots were 40.224μgTPF·g^-1FW·h^-1,compared with other treatments,it showed especial significant difference.The proportion of NH₄⁺-N was above and beyond 10%,all the indexes all descended.(3)The experiment of different consistency indicated:various indexes of different consistency treatments were get an advantage of clean water contrast.1.5 times consistency was suitable to best of all,and then was one times and double times,worst consistency was half.Dry weight of the plant was 4.303g with 1.5 times consistency,compared with 1.5 times consistency,there were no significant difference,but there were extremely significant difference with other treatments.