Effects Of The Optimum Fertilizer Formula And Its N, P, K Elements On Growth And Expression Of Relative Genes Of Betula Platyphylla

Reasonable fertilizer of forest could significantly promote the growth of tree heigh and diameter, increasing the seedling biomass. It also could accelerate flowering, increasing the number of fruit and flower bud. But in different growth stages, different trees need different nutrient elements. Thereofore, three fertilizer formulae (T1, T2and T3) of various nitrogen, phosphorus and potassium levels were applied to1-,2-and3-year-old birch (Betula platyphylla) seedlings of a half-sib family for2years, respectively, and set the non fertilization control. Then, by comparing their effects on seedling flowering and fruiting, we confirmed that T3was the best formula to promote the switch of birch from vegetative to reproductive development.Based on the best formula selected, we set the non fertilization control (CK) and investigated the effects of T3and its each element (N, P and K) on growth and development of birch seedlings for3years. Results showed that:In T3, the nitrogen element was the most effective in improving vegetative growth, making the3-year-old trees3.08m in height and26.33mm in caliper, an increase of19.38%and39.17%, respectively, over the control. The nitrogen fertilizer promoted flowering more effectively than the phosphorus or potassium fertilizer; applying nitrogen fertilizer improved the flowering rate of3-year-old trees to49%, compared to only4%,1%, and0%respectively, by applying only phosphorus, potassium or without applying fertilizer.The switch from vegetative to reproductive development is the major developmental transition in flowering plants. Plant apical meristem is changing from the endogenous metabolic pathways to external phenotype of this transition. And the MADS-box genes have important roles in it. Therefore, the research was monitoring the expression of12genes, including BpMADS2, BpMADS4, BpMADS6, BpMADS7, BpMADS8, BpMADS9, BpMADS12, BpMADS14, BpMADS15, BpAP1, BpFCA and BpFLC, which may have the function of controlling flowering of birch, after the treatment of T3, N, P, K and CK in2009. Then we analyzed the function of these genes by integrating the flowering rate of the year of2010and2011.First, we investigated the relative expression levels of12genes in the growth season (from May to September) in CK, and put them into four classes according to their expression pattern.Then, with CK as the reference, we studied these genes’expression levels and found that fertilization treatments increased the expression of most genes from May to August and reduced the expression of most genes in September. During May to August, only the expression of BpMADS9decreased in4fertilization treatments in most, while the expression of other genes most increased. Most particularly, the expression of BpMADS4, BpMADS9, BpFCA and BpFLC were closely related with fertilization treatments, also with the flowering rate. Under the condition of T3and nitrogen fertilization, the expression of BpMADS4raised, BpMADS9, BpFCA and BpFLC decreased, with a high flowering rate. While under the circumstance of phosphate and potassic fertilization, the expression of these genes were exactly the opposite, also with a low rate,In addition, we accumulated the expression of these genes from May to September; found that the total amount of these genes’expression reached significant level among the fertilization treatments and the non-fertilization control. The total amount of BpMADS4, BpMADS8, BpMAD514and BpAP1were higher under the condition of T3and nitrogen fertilization with a high flowering rate. Therefore we accounted for that the increasing amount of the4genes’ expression may accelerate flowering in birch.