Nutrient Solutions and Drought in Plant Growth and Fructans Content of Agave potatorum Zucc

Abstract

<jats:p>The <jats:italic>Agave potatorum</jats:italic> Zucc. is a wild species endemic to Oaxaca and Puebla, Mexico. The stem or “head” of the plants of this species contains a large amount of fructans, which, in conjunction with their crassulacean acid metabolism (CAM), helps the agave to survive droughts. The soluble carbohydrates are used to produce mezcal. The objective was to evaluate growth and content of fructans of <jats:italic>A. potatorum</jats:italic> young plants grown in soil and perlite substrate, fertigated with three nutrient solutions, and subjected to drought. Eight-month-old plants were used and, for 15 months, were fertigated with nutrient solutions: 1) Steiner, 2) Hoagland and Arnon, and 3) Urrestarazu. Irrigation was later suspended to simulate a 5-month drought and induce stress. During fertigation, the vegetative growth was greater in plants irrigated with Hoagland and Arnon and Urrestarazu solutions in perlite and in soil. After the period of water deficit stress, plants in perlite substrate fertigated with the Hoagland and Arnon solution accumulated more fructans in the heads, reaching a maximum of 75%, than plants in soil substrate (42%).</jats:p>

Effect of Water Stress Induced by Polyethylene Glycol on Growth, Proline Accumulation in Agave americana L.

“…The response to the decrease in biomass in A. americana L. plants under conditions of water deficit due to decreased irrigation was similar to that found in vitro using PEG. Langlé-Argüello et al [13] demonstrated a decrease in the number, thickness, and FW of the leaves in Agave potatorum Zucc. after 5 months of drought.…”

“…Peña-Valdivia et al [51] found a significant increase in proline accumulation from 1.6 to 2.1 mmol mg −1 DW in the roots of Agave salmiana when they were under stress conditions (−2.5 MPa). Langlé-Argüello et al [13] also studied the effect of water deficit and the physiological and morphological characteristics, and the generation of proline in roots. They evaluated the effect of restricted irrigation (−3.5 MPa) in eight species of Agave, having an average of 0.52 μmol 100 mg −1 of DW under frequent irrigation (−0.7 MPa).…”

“…Some studies in Agave under in vitro or soil conditions have shown that in the presence of water stress induced by PEG, an increase in root length occurs [11] and the suspension of prolonged irrigation does not affect the dry weight of the root and the aerial part [12]. In Agave potatorum Zucc plants, cultivated in perlite substrate and fertigated with Hoagland and Aron nutrient solution after five months of suspension of irrigation accumulated more fructans in the head [13]. However, it is not surprising that physiological research is mainly focused on water stress in model plants with the C 3 and C 4 metabolism types.…”