陇东雨养农区不同年龄和品种紫花苜蓿叶片氮磷重吸收特性

发布时间：2018-03-25 03:12

本文选题：紫花苜蓿　切入点：叶片养分重吸收　出处：《兰州大学》2017年硕士论文

【摘要】：叶片养分重吸收是植物叶片衰老脱落前将部分养分转移至其他成活组织的过程,是植物提高养分利用效率、增强环境适应性、响应干旱等逆境的重要策略之一。紫花苜蓿(Medicago sativa)是雨养农区的重要作物,能适应一定的贫瘠与干旱,且具有很强的生物固氮能力。但是,陇东雨养农区降水不均、土壤贫瘠,严重限制了苜蓿的高效、可持续利用。因此,进一步阐明其适应性有助于促进苜蓿的利用和推广。叶片养分重吸收是植物适应不同环境的重要机制之一,但其在不同年龄和品种下的表现并不明确。本研究以不同建植年龄(2、4、7、11和14年龄)和品种(陇东、阿尔冈金和新疆大叶)的紫花苜蓿为材料,分析了苜蓿叶片氮、磷重吸收特性及其调控规律,得到以下主要结果:1)建植年龄对苜蓿叶片氮、磷重吸收效率和重吸收度均影响显著(P0.05)。随建植年龄增大,叶片氮重效率(NRE)先增大后减小,叶片氮重吸收度(NRP)呈减小-增大-减小趋势。叶片磷重吸收效率(PRE)变化与NRE类似,而叶片磷重吸收度(PRP)随建植年龄增长逐渐减小。一般地,不同年龄苜蓿氮、磷重吸收在刈割茬次间差异显著,且第一茬显著高于第二茬(P0.05)。2)叶片氮、磷重吸收的品种间差异较小(P0.05)。NRE仅在1年龄第一茬时新疆大叶显著低于阿尔冈金和陇东,1年龄第二茬、2年龄第一茬时陇东分别显著低于阿尔冈金和新疆大叶(P0.05)。NRP仅在1年龄第一茬时新疆大叶显著低于陇东,2年龄第一茬时与之相反(P0.05)。PRE仅在2年龄第一茬时陇东显著低于阿尔冈金和新疆大叶,2年龄第二茬时阿尔冈金显著高于新疆大叶(P0.05)。PRP仅在2年龄第二茬时陇东显著低于阿尔冈金(P0.05)。1年龄苜蓿的第一茬和第二茬叶片氮、磷重吸收效率和重吸收度均分别低于2年龄,且第一茬显著高于第二茬(P0.05)。3)成熟叶和衰老叶氮、磷浓度对氮、磷重吸收效率和重吸收度影响显著(P0.05)。一般地,氮、磷重吸收效率分别与成熟叶氮、磷浓度显著正相关,与衰老叶氮、磷浓度显著负相关(P0.05),成熟叶氮、磷浓度分别负向调节氮、磷重吸收度。4)土壤矿质有效养分对叶片氮、磷重吸收具有影响。不同年龄陇东苜蓿第一茬时,硝态氮负向调节NRE和NRP,铵态氮则发挥正向调节作用;有效磷负向调节PRE和PRP。5)生物固氮对叶片氮、磷重吸收也产生影响。不同年龄陇东紫花苜蓿第一茬时的生物固氮率达51%,与NRE和PRE显著负相关(P0.05),但与NRP和PRP相关性较弱。第二茬时的生物固氮率为34%,与NER、PRE呈负相关性但不显著(P㩳0.05),与NRP和PRP的相关性也较弱。不同品种苜蓿的生物固氮对氮、磷重吸收的调节作用无明显规律。综上所述,紫花苜蓿叶片氮、磷重吸收受品种间的遗传差异的影响较小,但在不同年龄和茬次间差异显著(P0.05)。
[Abstract]:Leaf nutrient reabsorption is the process of transferring some nutrients to other surviving tissues before leaf senescence and shedding. Alfalfa (Medicago sativa) is an important crop in rain-fed farming areas, which can adapt to certain barren and drought, and has strong biological nitrogen fixation ability. However, rainfall is uneven and soil is poor in the Rain farming area of East Gansu. Therefore, further elucidation of its adaptability is helpful to promote the utilization and popularization of alfalfa. Nutrient reabsorption in leaves is one of the important mechanisms for plants to adapt to different environments. However, the performance of alfalfa at different ages and varieties was not clear. In this study, the leaf nitrogen of alfalfa was analyzed with alfalfa varieties (Longdong, Algangjin and Xinjiang large leaves). The characteristics of phosphorus reuptake and its regulation were studied. The main results were as follows: 1) the age of establishment had a significant effect on nitrogen, phosphorus reabsorption efficiency and reabsorption degree of alfalfa leaves. With the increase of plant age, leaf nitrogen and weight efficiency (NREs) increased first and then decreased. Leaf phosphorus reabsorption efficiency (PRE) was similar to that of NRE, while leaf phosphorus reabsorption decreased with the increase of planting age. Generally speaking, the nitrogen content of alfalfa at different ages decreased gradually, but the change of leaf phosphorus reabsorption efficiency (PRE) was similar to that of leaf P reabsorption efficiency (PRE), but the leaf P reabsorption ratio (P reabsorption) decreased gradually with the increase of planting age. Phosphorus reuptake was significantly different among cutting times, and the first crop was significantly higher than that of the second crop (P0.05N. 2), and the nitrogen of the first crop was significantly higher than that of the second crop (P0.05N. 2). The difference of P reuptake among cultivars was smaller than that of Algangjin and Longdong in the first year. NRE was significantly lower in Xinjiang than that in Algangjin and Longdong in the first year, respectively, compared with that in Algangjin and Xinjiang at the first year. NRP was only significantly lower in Longdong than that in Algangjin and Xinjiang at the first year of age. NRE was significantly lower than that of Algangjin and Xinjiang in the first year. In the first generation of age, Xinjiang leaves were significantly lower than those in east Gansu Province in the first generation, and in the first generation, they were significantly lower than those in Algangjin and Xinjiang in the second generation of the second generation of age, only in the first generation of the second generation of age, the level of Algangjin was significantly higher than that in Xinjiang. The nitrogen of the first and second crop leaves of alfalfa was significantly lower in Longdong than that in Algangjin P0.051.The first and second crop of alfalfa were only in the second generation of age. Phosphorus reabsorption efficiency and reabsorption degree were lower than 2 years old respectively, and the first crop was significantly higher than that of the second crop (P0.05U. 3) nitrogen in mature leaves and senescent leaves. Phosphorus concentration had a significant effect on nitrogen, phosphorus reabsorption efficiency and reabsorption degree. Phosphorus reabsorption efficiency was positively correlated with leaf nitrogen and phosphorus concentration, and negatively correlated with leaf N and P concentration. Leaf N and P concentrations were negatively regulated by N and P concentrations in mature leaves, respectively. In the first crop of Longdong alfalfa at different ages, nitrate negatively regulated NRE and NRP, ammonium played a positive regulatory role, and available phosphorus negatively regulated PRE and PRP.5) biological nitrogen fixation on leaf nitrogen. The biological nitrogen fixation rate was 51in the first crop of Longdong alfalfa at different ages, significantly negatively correlated with NRE and PRE, but weakly correlated with NRP and PRP. In the second crop, the biological nitrogen fixation rate was 34%, which was negatively correlated with NERP PRE, but not significant (P0. 05%). The effect of biological nitrogen fixation on nitrogen and phosphorus reuptake was not obvious in different alfalfa varieties. In conclusion, nitrogen and phosphorus reuptake in alfalfa leaves was less affected by genetic differences among varieties. But there were significant differences between different ages and stubble times (P 0.05).
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S541.9

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