氮(N)是以硝酸盐和铵的形式可用于植物的必需营养素。它是植物生长发育的重要营养元素,尤其是谷类作物,消耗它来生产氨基酸,蛋白质/酶,核酸,细胞壁复合物,植物激素,和维生素。在水稻生产中,生产1吨水稻需要吸收17kgN。考虑到这一点,已经开发了许多技术来评估叶绿度或SPAD值,以评估水稻品种中氮素的施用量,以最大程度地提高谷物产量。本研究的目的是研究在1.00×(全N)下三种不同基因型(MT2,RD31,KDML105)水稻中N同化的形态生理特征和相对表达水平,0.50×,0.25×(N损耗),比较了苗期和0.00×(缺氮)以及1.00×(全氮)和0.25×(耗氮)下的形态生理性状和籽粒产量属性。在缺氮条件下,水稻幼苗叶片黄化和生长抑制明显。射击高度,叶子的数量,射击新鲜的重量,芽干重,缺氮条件下KDML105的根鲜重降低了27.65%,42.11%,65.44%,47.90%,比对照组(全N)高54.09%。同样,在缺乏氮的情况下,KDML105的叶绿度最低(比全部氮减少78.57%),导致低光合能力。此外,氮同化相关基因的表达,OsNR1,OsGln1;1和OsGln2,在氮消耗下KDML105在3小时内增加,然后在长时间孵育后下降。而这些在简历中没有变化。MT2和RD31。同样,OsNADH-GOGAT的相对表达水平,OsFd-GOGAT,KDML105中的OsAspAt1在接受0.50×N6h时达到峰值,然后在长时间孵育后下降。此外,cv的整体生长特征和生理变化。在0.25×N下营养阶段的RD31比cvs更好地保留。KDML105和MT2,导致收获过程中的高产率。总之,氮耗竭条件下水稻幼苗中氮同化相关基因在3-6h内迅速受到调控,尤其是cv.KDML105和MT2,然后下调,导致生理变化,生长抑制,和产量减少。
Nitrogen (N) is an essential nutrient available to the plants in form of nitrate and ammonium. It is a macronutrient important for the plant growth and development, especially in cereal crops, which consume it for the production of amino acids, proteins/enzymes, nucleic acids, cell wall complexes, plant hormones, and vitamins. In rice production, 17 kg N uptake is required to produce 1 ton of rice. Considering this, many techniques have been developed to evaluate leaf greenness or SPAD value for assessing the amount of N application in the rice cultivar to maximize the grain yield. The aim of the present study was to investigate the morpho-physiological characteristics and relative expression level of N assimilation in three different rice genotypes (MT2, RD31, KDML105) under 1.00 × (full N), 0.50 × , 0.25 × (N depletion), and 0.00 × (N deficiency) at seedling stage and the morpho-physiological traits and the grain yield attributes under 1.00 × (full N) and 0.25 × (N depletion) were compared. Leaf chlorosis and growth inhibition in rice seedlings under N deficiency were evidently observed. Shoot height, number of leaves, shoot fresh weight, shoot dry weight, and root fresh weight in KDML105 under N deficiency were decreased by 27.65%, 42.11%, 65.44%, 47.90%, and 54.09% over the control (full N). Likewise, leaf greenness was lowest in KDML105 under N deficiency (78.57% reduction over the full N), leading to low photosynthetic abilities. In addition, expression of nitrogen assimilation-related genes, OsNR1, OsGln1;1, and OsGln2, in KDML105 under N depletion were increased within 3 h and then declined after the long incubation period, whereas those were unchanged in cvs. MT2 and RD31. Similarly, relative expression level of OsNADH-GOGAT, OsFd-GOGAT, and OsAspAt1 in KDML105 was peaked when subjected to 0.50 × N for 6 h and then declined after the long incubation period. Moreover, overall growth characters and physiological changes in cv. RD31 at vegetative stage under 0.25 × N were retained better than those in cvs. KDML105 and MT2, resulting in high yield at the harvesting process. In summary, N assimilated-related genes in rice seedlings under N depletion were rapidly regulated within 3-6 h, especially cv. KDML105 and MT2, then downregulated, resulting in physiological changes, growth inhibition, and yield reduction.