Dynamic Studies On Maize Kernal Development Under Tissue Culture Conditions

The research was conducted with two hybrids " nongdan 5" and " nongda108 " . The dynamics of kernel development and the influence factors for kernel development(environment temperature, minenal nutrients, growth regulation substance) were studied thoroughly under the condition in vitro. The results showed that:With the increase of NAA and ethylene concentration in the culture, the abortion rate of maize kernel also increased. When GA was within the scope of low concentrations, kernel abortion rate showed the increasing tendency; But when it was within the scope of high concentrations, kernel abortion showed the decreasing tendency. With the increase of NAA concentration, dry weight and fresh weight of maize kernel decreased; When GA was within the scope of low concentrations , along with the increase of GA concentrations, dry weight and fresh weight of maize kernelalso decreased; But when GA was within the scope of high concentrations, it showed the increasing tendency. If we made use of ethylene of low concentrations or high concentrations, fresh weight of kernel showed the decreasing tendency ; when ethylene was in the middle concentrations, fresh weight of kernel showed the increasing tendency.When GA was used in low concentrations or high concentrations, both germination rate of kernel and α -amylase activity showed the increasing tendency; But when GA was used in middle concentrations, the two kinds of enzyme activity showed decreased tendency.As maize kernel of different parts were cultivated in vitro, they could grow to maturity in the end and had no obvious difference in t kernel weight compared to those growing in the field.This experiment proved that respiration rate of maize kernel and accumulative dynamics of dry matter under culture in vitro were similar to that of maize kernel in the field.The content of soluble sugar in kernel kept a relatively higher level the other day after pollination; with the increase of maize kernel, the content of soluble sugar became gradually lower; it kept a low level in the end. Fresh kernel weight, starch content, protein content as well as kernel bulk slowly increased in the first 10 days after pollination; they began to develop rapidly after 10 days. Their growth dynamics behaved S curve.This test proved that there were synchronization tendency between respiration dynamics of per unit weight and kernel weight during kernel development under culture in vitro. This reflected that there was closely correlation between respiration rate of kernel and accumulation content of kernel dry matter.