关键词: 气候变化, 气候变化, 冬小麦, 夏玉米, 生育期, 影响

Abstract: The paper aims to understand the early developmental characteristics of ontogeny of Nymphoides indica. The morphological structure from seed to seedling of N. indica was observed using a combined way of morphologic observation and conventional paraffin section technique. The results showed that papillary sculpture was on the surface of the seed, higher embryo differentiation was found when the seed was leaving the matrix, the root and seedling had no clear differentiation in the mature embryo stage. During the seed germination, the hypocotyl elongated, and the radicle broke through seed coat. In this stage, the root collar rose from the junction between the hypocotyl and the radicle, and then, the collet hairs were sprouting in the field of the root collar. The collet hairs of root had single cell structure, developed from the outward depression of epidermal cell, and they were different from the root hairs in the time and place of appearance. The cotyledon stage of seedlings lasted for at least 10 days, and during this period, the root developed from the taproot system to the fibrous root system. At the stage of the fruit maturity, most of embryo in N. indica developed to mature embryo stage. The root collar and collet hairs appeared from the junction between the hypocotyl and the radicle during the early stage of seed germination. The development of roots was faster than that of seedlings. So, it can be inferred that the early developmental process of N. indica from seeds to seedlings has the hydrophilous developmental traits, and the late developmental process has the terrestrial developmental traits.