Page 91 - 《广西植物》2023年第12期
P. 91

12 期        依里帆艾克拜尔江等: 两种豆科植物及各器官对不同形态氮的吸收、分配研究                                         2 2 5 7

                 Abstract: Legumes are abundant in the nitrogen deficient desert ecosystemsꎬ which is the center of supplying available
                 nitrogen and the important pioneer species in this region. Howeverꎬ the studies on nitrogen uptake and utilization by
                 legumes in desert ecosystems have rarely been reported so far. In this study Astragalus flexus and A. arpilobusꎬ which are
                 widely distributed in the Gurbantunggut Desertꎬ were selected as the research objects. Three different nitrogen forms
                  15     +  15    -  15
                 ( N-NH ꎬ N-NO ꎬ     N ̄glycine) were added to 0- 5 cm and 5- 15 cm soil layersꎬ respectivelyꎬ to study the
                        4        3
                 absorption and distribution strategies of different forms of nitrogen in two plants and their organs. The results were as
                 follows: (1) In different soil layersꎬ both plants preferred to absorb nitrate nitrogenꎬ and the maximum absorption rates
                                                          ̄1    ̄1
                 of A. flexus and A. arpilobus were 3.26ꎬ 2.59 μgg  h ꎬ respectively. (2) In different soil layersꎬ there were
                 significant differences in the uptake and allocation of different nitrogen sources among plant organs (P< 0.05). The
                        15
                 uptake of N in root of A. flexus was higher than that of A. arpilobusꎬ and the three different nitrogen forms were mainly
                 allocated to leaves. (3) In different soil layersꎬ the contribution rates of different nitrogen sources to both plants were
                 15    -  15        15     +
                  N-NO >   N ̄glycine >  N-NH ꎬ and the contribution rates of nitrate nitrogen to nitrogen absorption of A. flexus
                       3                   4
                 ranged from 37% to 41%ꎬ while the maximum contribution rate to the nitrogen absorption of A. arpilobus was 45%. (4)
                 There were significant differences in recovery rates of different nitrogen forms between different organs of plants (P<
                 0.05). In the 0-5 cm soil layerꎬ the recovery rate of nitrate nitrogen was leaf > stem > rootꎬ while in the 5-15 cm soil
                 layerꎬ the rate was leaf > root > stem. In generalꎬ in the Gurbantunggut Desert ecosystemꎬ different life forms legumes
                 had both consistency and difference in nitrogen uptake and allocation capacityꎬ and were affected by different soil depths
                 and nitrogen forms. The results provide theoretical basis for nitrogen uptakeꎬ utilization and allocation of legumes in arid
                 and semi ̄arid regions of Xinjiang.
                 Key words: legumesꎬ plant organꎬ isotopic labelingꎬ nitrogen uptakeꎬ Gurbantunggut Desert



                氮素是植物所有必需营养元素中限制生长的                            快且偏好吸收利用( 侯宝林ꎬ2022)ꎮ 而喜铵植物
            第一元素ꎮ 氮素的来源和分配既影响氮素利用率                             如水稻(Oryza sativa)、马尾松( Pinus massoniana)、

            又会改变氮素内循环和周转( Hooper & Johnsonꎬ                    铁 芒 其 ( Dicranopteris linearis )、 白 云 杉 ( Picea
            1999ꎻ Kou et al.ꎬ 2015ꎻ 陶冶等ꎬ2016ꎻ Zhou et al.ꎬ     glauca)和苍耳( Xanthium sibiricum) 等偏好吸收利
            2018)ꎮ 可被植物吸收利用的氮素形态主要有硝                           用 铵 态 氮 ( Fried et al.ꎬ 1965ꎻ Wallander et al.ꎬ

            态氮、铵态氮和有机氮( Wang et al.ꎬ 2016ꎻKaur et              1997ꎻ Leeꎬ 1998ꎻ Li et al.ꎬ 2013ꎻ 孙思邈ꎬ2020)ꎮ
            al.ꎬ 2016)ꎮ 植物从土壤中吸收氮的形态和多少                            全世界的豆科植物约 765 属 19 500 种ꎬ广布
            在全球氮素循环中处于非常重要的地位ꎬ但由于                              于全球(Zhao et al.ꎬ 2021)ꎬ中国约有 184 属1 234
            植物本身生物特征及生长环境的差异ꎬ加上不同                              种ꎬ各省(区)均有分布( 熊义勤和汪自强ꎬ2018)ꎮ
            形态的氮素对植物生长的有效性不同ꎬ因此不同                              豆科植物在荒漠等干旱区生态系统大量存在ꎬ既
            形态氮素对不同植物生长的贡献存在差异( 侯宝                             是生态系统提供有效氮的中心也是这一区域重要
            林和庄伟伟ꎬ2021)ꎮ 不同植物在对氮素营养环境                          的先锋物种( Allen & Allenꎬ 1981)ꎮ 20 世纪大多
            的长期适应过程中形成对不同氮源的偏向性选                               研究 都 认 为 只 有 铵 态 氮 和 硝 态 氮 ( Schimel &
            择ꎬ最 终 形 成 了 不 同 的 氮 素 利 用 与 分 配 策 略                Bennettꎬ 2004)能够直接被植物吸收利用ꎬ随着对

            ( Tegeder & Masclauxꎬ 2018ꎻ Zhuang et al.ꎬ 2022)ꎮ  植物氮素营养的深入研究ꎬ学者们逐渐发现植物
            根据植物对不同形态氮素的偏好吸收利用ꎬ将植                              可以 利 用 土 壤 中 的 可 溶 性 有 机 氮 ( 莫 良 玉 等ꎬ
            物分为喜硝型植物和喜铵型植物( McKane et al.ꎬ                     2002ꎻ王文颖和刘俊英ꎬ2009)ꎮ 在极受氮素限制
            2002)ꎮ 一些喜硝植物如尖喙牻牛儿苗( Erodium                      的系统如高山、北方和冻原生态系统中ꎬ有机氮的
            oxyrrhynchum)、琉苞菊( Hyalea pulchella)、假狼紫           吸收是一个非常重要的方式( 冯彦丽ꎬ2020ꎻ杜流
            草( Nonea caspica)、飘带果( Lactuca undulata)、角         姗ꎬ2020)ꎮ 张玉琪等(2021) 的研究发现ꎬ扁蓿豆
            果 藜 ( Ceratocarpus arenarius )、 碱 蓬 ( Suaeda       (Trigonella ruthenica) 各 器 官 对 氮 积 累 量 大 小 为
            glauca)等对硝态氮吸收能力强ꎬ在硝态氮下生长                          茎<花<叶ꎮ 不同植物功能群的氮素吸收特点、分
   86   87   88   89   90   91   92   93   94   95   96