| The mineral nutrition charactertic and the selection of culture media were explored deeply which combined with the actual production about Oncidium.In order to get them; we used sampling methods and pot experiments along with lab experiments. The research contents included distribution, accumulations, and contents of mineral elements in each growing stage of Oncidium.The physical and chemical properties of growing medias were also studied. Preliminary discussed those mixed medias which were mixed according to different proportion produced effects on their physical and chemical properties. In order to test the feasibility of these mixed media used in Oncidium production, a study was conducted to access the effect of mixed media on growth of Oncidium.Main equations as following:1. With the same distribution rule of dry matter about Oncidium in different organs each growth period, there were the most in leaves, least in roots, and pseudobulb were placed in middle. The accumulation of dry matter in flower branches was twice as much as flowers. Every pseudobulb could accumulate dry matter about0.16g in seedling stage,0.81g in initial bloom,1.76g in bloom stage. Beginning from seedling to bloom, the growth rate got highest. It showed that pseudobulb needed a lot of dry matter in this growth stage.2. With the same distribution rule of nitrogen, phosphorus, potassium and calcium about Oncidium in different organs each growth period. The most nitrogen, potassium, calcium in leaves and phosphorus in pseudobulb.The highest levels of magnesium was in initial bloom and bloom stage. The proportion of total nutrition accumulation of N,P,K,Ca,Mg,S were1:0.41:1.57:0.38:0.22:0.16in seedling stage,1:0.27:1.45:0.32:0.23:0.14in initial bloom and1:0.31:1.62:0.32:0.24:0.19in bloom stage.1:0.12:0.78:0.09:0.08:0.08in orangans of cut flowers. To produce a pseudobulb would need N1.16mg、P0.70mg、K1.52mg、Ca0.53mg、Mg0.37mg、S0.22mg in seedling stage, N9.31mg、P3.69mg、K10.71mg、Ca3.55mg、Mg2.93mg、S1.57mg in initial bloom and N22.63mg、P10.24mg、K31.49mg、Ca6.93mg、Mg7.05mg、S4.82mg in bloom stage. With the highest distribution of N, Ca in leaves, they reached50.35%and55.46%.In initial stage, K in leaves reached68.50%was the highest, following leaves in seedling stage, and leaves in bloom stage.3. With the passage of time, demands of trace mineral elements continued to grow especially bloom stage. In initial and bloom stage, trace elements had similar distribution rule. Accumulation of Mn in seedling stage got to the highest. From seedling into initial bloom and bloom stage, the amount of Fe was more than Zn which were accumulated and absorbed in orchid’s plants. The accumulation of Fe became the most in all of trace elements. So, This showed that Fe was linked to the formation of flower buds about Oncidium probably. Through the study found that, roots’absorption of Zn about Oncidium was strong and the demand was biggest relatively.4. The bulk densities of all growing medias reached the required standards which were appropriate for plant cultivation. All of the treatments’water-filled porosities had a range of10.45-29.64%, and their size relationship was A>B>C.The biggest one reached29.64%and the least value was22.17%in A. The biggest one had reached19.41%and the least value was11.99%in B The biggest one reached15.41%and the least value was10.45%in C. Sphagnum had the best performance of water in four main growing medias; following by coconut clothing block. Pine bark was similar to vesuvianite.5. Compared to all treatments, coconut clothing block and related combinations had the highest salt content. EC values of most matrixes were suitable for growth of roots. Some of those matrixes had higher EC. In all treatments, pH and EC changed as the time went by. Generally speaking, pH over time would be reduced and EC would be raised. pH of vesuvianite and sphagna combinations had the biggest reductions and was out of the appropriate pH scope.6. The simulated growth rate of combination composed of vesuvianite and sphagna were best, and then vesuvianite and pine bark. The combination composed of vesuvianite and coconut clothing blocks were worst. The root activities of the three combinations had following relationship about A>B>C. It showed that the best combinations were vesuvianite and sphagna.The root activity of B6reached23.73μ.g-1·h-1DW, which was maximum in all treatments. However, compared with A, the difference was not significant, but significantly higher than the control (CK3).This suggests that the growing medias of vesuvianites mixed coconut clothing blocks were better than treatments of pure coconut clothing blocks.7. In all treatments, there were the biggest biomass about the combinations of vesuvianite and sphagna. In general, the relationship of accumulation of N, P, and K was that A was higher B and C. The treatment of C had maximum content of Ca. With the maximum comprehensive evaluation index, treatments A were best for growth of Oncidium. Despite comprehensive evaluation index of pure sphagna had gotten maximum, however, the EC, pH and bulk density would produce bigger change as time went by, which were not suitable for scale production. So, it was not considered for reasonable matrix.According to the comprehensive conclusion showed the best growing medias for Oncidium. A1, A2, A4and A5were best for Oncidium’s cultivation in seedling stage. In adult period, B4and C7were the best combinations. On account of how easily we can get from local substrates in Hainan, the combinations of vesuvianite and coconut clothing block were advisable, especially B4. |
PDF Full Text Request