Study On Characteristics Of Morphological Structure And Vigor Of Different Types Of Maize Seeds (Zea Mays L.)

This research was conducted with 8 different types of maize seeds (16 varieties in all) in order to research the morphological and structural differences, seed vigor and their relation to water uptake, germination and seedling emergence. The results showed that:There was significant difference of 100-kernel weight between different types of maize seeds. The 100-kernel weight of different types of maize seeds from high to low in order was: dent type, high oil type, high lysine type, half-dent type, waxy type, flint type, sweet type and pop type. Of all the types of maize seeds, 100-kernel weight was relative to the absolute contents of soluble sugar, starch, protein, and the relativities of 100-kernel weight to the absolute contents of starch and protein were significant. Except the sweet type, the relativities of 100-kernel weight to the absolute contents of soluble sugar, starch, protein were significant. The higher the 100-kernel weight, the higher proportion of the endosperm to the whole kernel and the store substances of the seeds. 100-kernel weight of the seed was relative to the fresh weight, height and seed vigor of the seed under the artificial accelerated aging treatment.For all the varieties in this research, the thickness of the cortex did not have a significant influence on the speed of water uptake of the seeds, and the proportion of the embryo and that of the embryo to the endosperm were the main factors. The cortex thickness and its proportion to the whole kernel had a negative relation to the indexes of the germination and seedling of different types of maize seeds, and the relation of the cortex proportion to seed germination was more close to that of the cortex.The relativities among the germination viability, germination rate and vigor index of different gene types were significant under the standard and the artificial accelerated aging germination test. The relativities of the germination viability and germination index to the vigor index were significant. The relativity of the seedling fresh weight to the vigor index was higher under the artificial accelerated aging testthan that of under the standard germination test.As the 100-kernel weight, the proportion of every part to the whole kernel was different among different types of maize seeds, so the TTC activities of different types of maize embryo can not represent the activities of the whole kernel.This research used the seed vigor index under the artificial accelerated aging test as the standard of seed vigor evaluation. After the artificial accelerated aging treatment, the germination viability, germination rate and germination index were lower than that of under the standard condition, and the decrease of the special types of maize seeds was higher than the conventional types. Under the artificial accelerated aging test, the vigor of conventional types of maize seeds was higher than that of the special types. Among the eight different types of maize seeds, seed vigor of half-dent type, dent type, flint type and high oil type was higher, and that of waxy type, pop type, sweet type and high lysine type was lower.