Growth regulation of Isoetes sinensis seedings planted in several substrates

Isoetes sinensis is an ancient vascular plant in mires, and Chinese unique, critically endangered now and key wild plant for state protection. The seedlings of Isoetes sinensis were planted in the 6 kinds of substrates with different proportions of the dark brown soil and the sand from river, the vegetative and reproductive growth of the seedlings were studied in the green house of Key Laboratory of Botany of Heilongjiang Province during February 5 2010 to October 5 2012. Comparing the number of seedling leaves, the leaf lengths, formation of sporangium and condition of maturation under 6 kinds of substrates and 4 kinds of thicknesses of the dark brown soil, the suitable substrate for Isoetes sinensis growth was chosen. The resuits showed that the more proportion of the dark brown soil in the substrates, and the thicker of the dark brown soil, the more number of seedling leaves and the longer of leaf lengths of Isoetes sinensis, and the shorter time the sporangium grew and the spores matured. The higher proportion of the sand in the substrates would result in Isoetes sinensis seedling death or spore abortion, the environment with nutrient rich, little or no sand, shallow micro flow, high water quality, light transparent enough in the mires fits for the growth of Isoetes sinensis.