Rice Dry Seedbed Seedling Characteristics And High Yield Cultivation Techniques

The experiments with seven varieties, wuyujing 3, shanyou 63, wuyunjing 7, wuyunjing 8 and wuxiangjing 9 as representative cultivars, in two cultivation styles (cultivation of dry and wet) were carried out to determine the. The major results were as follows: 1. Compared with wet seedbed seedlings, the leaf emergency rate of dry seedbed seedlings is slower, the seedlings are smaller and in an inferior condition. But the number of tiller and root are in a dominant condition, especially the early tillers. 2. The contents of soluble sugar and starch in leaf, stem and sheath, root and the whole plant of dry seedbed seedling are obviously higher. The difference of soluble sugar is larger than that of starch. Carbohydrates stored in stem, sheath and leaf of dry seedbed seedlings are higher. The total nitrogen content in dry seedbed seedlings is obviously higher than that in wet seedbed seedlings, and the content in leaf is highest, the content in stem is secondly, the content in root system is lowest. Dry seedbed seedlings have more content of NOj-N obviously, the order of the content of NO;-N in different organ is stem and sheath, root system, leaf. While that order in wet seedbed seedlings is root system, stem and sheath, leaf The content of soluble protein, chlorophyll and proline in leaf in dry seedbed seedlings are higher too. 3. In dry seedbed seedlings, the weights of dry and wet of root are lower, but the number per plant, weight are higher obviously, absorbing area and root vigor are obviously higher too. 4. In the course of transplanting, in dry seedbed seedlings, the content of GA, CTK, IAA in the leaf and the content of GA, CTK in the root are obviously lower, but the content of ABA in the leaf and the contents of ABA, IAA in the root are obviously higher. On the third day after transplanting, the contents of GA, CTK, IAA in the leaf and root of dry seedbed seedling increased quickly and these are obviously higher than those of wet seedbed seedlings. But the content of ABA of dry seedbed seedlings is decreased with large extent. All these indicated that water stress before transplanting hold back the growth of shoot nutritious organ, but the effect on root system is small. And after transplanting, because the seedlings were released from the water stress, they grew very quickly. 5. After transplanting, the number and the length of new root of dry seedbed seedlings are higher, but with the time past, the intensity of new root emergence became more and more weaken. After transplanting, the root system of dry seedbed seedlings has more amounts and vigor from returning green to heading.These are the important physiological basis of rapid growth after a transplanting. 6. Compared with wet seedbed seedlings, the leaf emergence rate is quicker before 2.5 leaf age, but the mean leaf emergence rate during the whole seedling is 0.03 per day lower than that of wet seedbed seedlings. And after transplanting, the leaf emergence rate was obviously picked up. Twenty days after transplanting, the leaf ages among two kinds of cultivation seedlings are almost same. Finally, the total leaf number of dry seedbed seedlings is 0.5 more than that of wet seedbed seedlings. The superiority of tiller in dry seedbed seedlings is distinct, especially the early tillers. The development of colony leaf area index are smooth. And the colony accumulation of dry matter is higher with dry seedbed seedlings, especially fr...