Physiological and biochemical responses of Agave to temperature and climate of their native environment

Abstract

The assessment of phenotypic variation across populations can help to select genotypes that are potentially resistant to the ongoing and predicted climatic variations. Phenotypic variation is expressed as morphological, physiological, or metabolic changes in response to environmental factors. Agave mapisaga and A. salmiana populations exhibit morphological variation regarding their geographical distribution and due to intense anthropogenic influence. This study aimed to identify metabolic traits in young plants of A. mapisaga and A. salmiana, involved in plant resistance to temperature stress, which can help to understand differences between provenances and between species. Agave plants propagated from four seed origins, collected from three “pulque” (a fermented beverage) production areas in the state of Hidalgo, Mexico, were assessed. Four-month-old plants of each seed origin (species*provenance) were maintained during one month in growth chambers, at day/night temperature (T) regimes for 12/12 h: (1) 25/25T, (2) 25/15T, and (3) 25/15 plus 45 °C T for 4 h between 11 am and 3 pm (45T). The plant dry biomass, maximum quantum efficiency of PSII photochemistry (Fv/Fm), total free amino acids (TFAA), total free phenol (TFP), and free soluble sugar concentrations were measured. Minimum values for dry biomass, TFP, glucose, and sucrose concentrations occurred in the 25/25T regime. Plant biomass, and TFAA and glucose concentrations were differently affected by seed provenances; but Fv/Fm rate, or the TFP, fructose, and sucrose concentrations had no relation to seed provenance. Moderate high night temperatures drastically affected the growth and metabolism of A. mapisaga and A. salmiana. In conclusion, the response to different temperature stress treatments depends partly on species, but less on seed provenance.