RESUMEN
Introduction: Alfalfa (Medicago sativa L.) is the favored premium feed ingredient in animal husbandry production which is in serious jeopardy due to soil moisture shortages. It is largely unknown how different root types of alfalfa respond to arid-induced stress in terms of metabolites and phytohormones. Methods: Therefore, rhizomatous rooted M. sativa 'Qingshui' (or QS), tap-rooted M. sativa 'Longdong' (or LD), and creeping rooted M. varia 'Gannong No. 4' (or GN) were investigated to identify metabolites and phytohormones responses to drought conditions. Results: We found 164, 270, and 68 significantly upregulated differential metabolites were categorized into 35, 38, and 34 metabolic pathways in QS, LD, and GN within aridity stress, respectively. Amino acids, organic acids, sugars, and alkaloids were the four categories of primary differential metabolites detected, which include 6-gingerol, salicylic acid (SA), indole-3-acetic acid (IAA), gibberellin A4 (GA4), abscisic acid (ABA), trans-cinnamic acid, sucrose, L-phenylalanine, L-tyrosine, succinic acid, and nicotinic acid and so on, turns out these metabolites are essential for the resistance of three root-type alfalfa to aridity coercing. Discussion: The plant hormone signal transduction (PST) pathway was dramatically enriched after drought stress. IAA and ABA were significantly accumulated in the metabolites, indicating that they play vital roles in the response of three root types of alfalfa to water stress, and QS and LD exhibit stronger tolerance than GN under drought stress.
RESUMEN
Taking the salinized apple orchard soil in Qin'an County of Gansu Province, Northwest China as test object, a field experiment was conducted to study the effects of different irrigation quota (0, 900, 1800, 2700, and 3600 m3 x hm(-2)) on the redistribution of moisture and salt in 0-100 cm soil profile on the 10, 20, and 30 d during apple florescence stage. With the increase of irrigation quota, the leached depth of Na+ increased and its hysteretic effect of redistribution was more obvious, "the zero flux plane" of Ca2+ disappeared gradually, the scope of "the zero flux plane" of Mg2+ increased gradually, the leaching-migration mode of Cl- changed from "fluctuation" to "straight-line" and the evaporation-migration changed from "fluctuation" to "ladder", the redistribution pattern of SO4(2-) showed "point", and the position of redistribution and accumulation of HCO3- shifted gradually from the bottom to upper layer in soil profile. In the middle of the soil profile with deeper groundwater table, there existed a "zero flux plane" of salt, which shifted gradually from the upper layer to the bottom during the redistribution of moisture in soil profile, embodying the characteristics of moisture depletion in upland soils. When the irrigation quota was between 2700 and 3600 m3 x hm(-2), irrigation was helpful to the leaching of salt and water-soluble Na+ in the 0-100 cm soil profile. However, when the irrigation quota was < 1800 m3 x hm(-2), irrigation accelerated the salt accumulation in surface soil. Therefore, from the viewpoints of salt leaching and water-saving, an irrigation quota of 1800-2700 m3 x hm(-2) in spring would be more appropriate for the salinized apple orchard soil in arid regions.