{'fraction_non_alphanumeric': 0.023034154090548053, 'fraction_numerical': 0.012708498808578236, 'mean_word_length': 4.101214574898785, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Kinetics of Nitrate Uptake by Different Rice Genotypes and the Effects of Ammonium on Nitrate Uptake at the Seedling Stage

Solution culture experiments were carried out to study the kinetics of NO 3 - uptake by different rice genotypes, including 12 varieties of wetland rice and 2 varieties of upland rice, and the effects of NH 4 + on NO 3 - uptake were assessed. The results indicated that at the seedling stage (20 days) upland rice had higher maximum rate (V max) of NO 3 - uptake than wetland rice, Indica showed higher V max than Japonica, and Hybrid rice presented higher V max than common rice. The effects of NH 4 + on V max of NO 3 - uptake differed greatly among the rice genotypes: Indica rice was less influenced than Japonica rice; Hybrid rice was less restrained than common rice; upland rice was hardly inhibited; certain varieties of Indica rice and upland rice even were stimulated with the existence of NH 4 +. On account of the slight influence of NH 4 + on the values of K m of all tested genotypes, it seems that the effects of NH 4 + on NO 3 - uptake are mainly due to the influence on the transporting rate of nitrate carriers located at the cell membrane, but not due to the influence on the affinity of the uptake sites for NO 3 -.