Peña-Becerril Juan C, Monroy-Ata Arcadio, Orozco-Almanza María del Socorro, García-Amador Esther Matiana
Rev Biol Trop. 2016 Jun;64(2):791-803. doi: 10.15517/rbt.v64i2.20289.
Mexico is dominated by arid or semi-arid ecosystems, predominantly characterized as xeric shrublands. These areas are frequently deteriorated due to agriculture or over-grazing by livestock (sheep and goats). The vegetation type mainly consists of thorny plant species, and among these, the dominant one in overgrazed areas is catclaw (Mimosa biuncifera). This is a nurse plant that facilitates establishment of other vegetation and promotes plant succession. Catclaw plants form a mutualistic association with arbuscular mycorrhizal fungi (AMF), which improves uptake of nutrients and water. The objective of this study was to determine the effect of inoculating catclaw plants with native AMF and starting their growth under a low water availability treatment in a greenhouse, and later transplanting them to field conditions of drought and deterioration. Field plants were evaluated according to their survivorship and growth. The seeds of catclaw plants and soil with AMF spores were collected in the Mezquital Valley of Hidalgo State, in Central Mexico. Seedlings were grown in individual pots in a greenhouse. The experimental design consisted of two levels of pot irrigation, wet (W) and dry (D), as well as the presence (M+) or absence (M-) of AMF inoculum, with 20 replicates for each treatment. The following plant parameters were recorded every week: height, number of leaves and pinnae, and mean diameter of coverage. After 20 weeks in the greenhouse, determination was made of fresh and dry biomass, relative growth rate (RGR), root/shoot ratio, real evapotranspiration (RET), water-use efficiency (WUE), and percentage of mycorrhizal colonization. The remaining plants growing under the dry treatment (M+ and M-) were then transplanted to a semi-arid locality in the Mezquital Valley. During one year, monthly records were kept of their height, number of leaves, mean diameter of coverage and survival. Results showed that compared to greenhouse plants under other treatments, those under the wet mycorrhizal (WM+) treatment were taller, had more pinnae, and were characterized by greater coverage, faster RGR, and greater fresh and dry biomass. Moreover, inoculated plants (WM+ and DM+) showed higher WUE than those uninoculated (WM- and DM-, respectively). After one year in field conditions, there was a higher survival rate for previously inoculated versus uninoculated plants. Hence, mycorrhization of M. biuncifera with native AMF inoculum increased plant efficiency in biomass production, thus favoring establishment and survival in field conditions. We concluded that inoculation of catclaw plants is recommendable for revegetation programs in deteriorated semi-arid zones.
墨西哥主要是干旱或半干旱生态系统，主要特征为旱生灌木丛。这些地区经常因农业活动或牲畜（绵羊和山羊）过度放牧而退化。植被类型主要由带刺植物物种组成，其中，过度放牧地区的优势物种是猫爪刺（含羞草）。这是一种护土植物，有助于其他植被的定植并促进植物演替。猫爪刺植物与丛枝菌根真菌（AMF）形成互利共生关系，这有助于提高养分和水分的吸收。本研究的目的是确定在温室中对猫爪刺植物接种本地AMF并在低水分供应处理下开始生长，随后将其移植到干旱和退化的田间条件下的效果。根据田间植物的存活率和生长情况对其进行评估。猫爪刺植物的种子和带有AMF孢子的土壤采集于墨西哥中部伊达尔戈州的梅斯基塔尔山谷。幼苗在温室中的单独花盆中生长。实验设计包括两种花盆灌溉水平，即湿润（W）和干燥（D），以及AMF接种物的存在（M+）或不存在（M-），每种处理有20个重复。每周记录以下植物参数：高度、叶片和羽片数量以及覆盖平均直径。在温室中生长20周后，测定鲜重和干重生物量、相对生长率（RGR）、根冠比、实际蒸散量（RET）、水分利用效率（WUE）以及菌根定殖百分比。然后将在干燥处理（M+和M-）下生长的其余植物移植到梅斯基塔尔山谷的一个半干旱地区。在一年时间里，每月记录它们的高度、叶片数量、覆盖平均直径和存活率。结果表明，与其他处理下的温室植物相比，湿润菌根（WM+）处理下的植物更高，羽片更多，覆盖面积更大，RGR更快，鲜重和干重生物量更大。此外，接种植物（WM+和DM+）的WUE高于未接种植物（分别为WM-和DM-）。在田间条件下生长一年后，先前接种的植物比未接种的植物存活率更高。因此，用本地AMF接种物对含羞草进行菌根接种可提高植物生物量生产效率，从而有利于在田间条件下的定植和存活。我们得出结论，对于退化半干旱地区的植被恢复计划，推荐对猫爪刺植物进行接种。
