Effects of two media and fertilizer levels on the growth of Cymbidium hybridium were studied. Results demonstrated that peanut\|hull mixed sand (abbreviated as PH/S=1/1) medium had higher total porosity and larger air space and lower water holding capacity in comparison with sphagnum (abbreviated as SP) medium. Leaf growth rate, chlorophyll contents, fresh weight and photosynthetic rate change along with the changes of nitrogen concentrations of both SP and PH/S media. According to the investigation,when the nitrogen concentration was 222 75?mg·L -1 , the photosynthetic rate of SP\|medium reached the highest. The practical nitrogen content was 180 00?mg·L -1 for PH/S medium . The maximum of flower quantity (number per spike) was gotten by treating of N/P 2O 5/K 2O=10/30/20 on PH/S medium, and N/P 2O 5/K 2O=0/23/29 treatment was the lowest on PH/S medium. The differences in small flowers, stem length and flower quantity among the two media and the three fertilization methods reached significant at 0 05 level,respectively.
To get high flower production of tuberose,growing media and NPK fertilizer proportion was determined accurately by polynomial regression quadratic equation (PRQE) in four elements.The partial derivatives from polynomial regression equation ( 6) was utilized for estimating the maximum production of tuberose flower.Results revealed coding level X 1=-1 695, X 2=-1 122 ,X 3=0 311 and X 4=1 151,which are converted into doses of trial factors,are KD-1-Hydrophilic gel/sandy-soil (HG/SS)=0 652%,(NH 4) 2SO 4=14 39 (g·m -3 ),Ca(H 2PO 4) 2·H 2O=25 75 (g·m -3 ) ,and K 2SO 4=25 89 (g·m -3 ).Therefore, max =28 79 (number of flower·m -2 ).Results revealed that plant height was significantly influenced by the application of three major nutrients.However,number of leaves/plant increased non-significantly with the increasing level of NPK and HG/SS.Number of bulks/clump was also influenced by N,P and K as well as HG/SS.Application of higher levels of NPK showed profound effect on increasing flower production (number of spikes·m -2 ),and number of florets/spike.Therefore,higher doses of NPK are recommended for higher production of flower.
