Seed germination of Agave species as influenced by substrate water potential.

Hugo M Ramírez-Tobías,Humberto Vaquera H,Carlos Trejo,J Rogelio Aguirre R,Cecilia B Peña-Valdivia

doi:10.1186/0717-6287-47-11

Hugo M Ramírez-Tobías, Humberto Vaquera H + Show 3 more

Open Access

https://doi.org/10.1186/0717-6287-47-11

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Abstract

BackgroundPlants of Agave spp. perform Crassulacean acid metabolism (CAM) and are highly drought-tolerant, but little is known concerning seed germination under low water availability. The aim of this study was to assess the effect of substrate water potential (ΨW) on seed germination and contrast hydrotime parameters of seven valuable and commercially-important Agave species from different geographical distributions and climatic regions of Mexico. Our hypothesis was that seed germination of Agave species is not affected by low water availability independently of seed biomass and the climate of their distribution area.ResultsSeed germination (at 25°C and in the dark) between 85 and 100% for all species occurred within 80–180 h at -0.03 MPa and 250–430 h at -1.0 MPa. Seed germination at -1.5 MPa declined to less than 50% (p < 0.05) for A. asperrima and A. cupreata but did not change significantly for A. americana var. marginata, A. lechuguilla and A. striata, although they showed the lowest mean base water potential (-2.01 to -2.64 MPa). Seed germination of 40% Agave species, from arid and semi-arid climates in this study, was not affected by the lower ΨW.ConclusionGermination of seeds of Agave species is moderately affected by low water availability, is partially dependent of their ecological distribution, and is independent of seed mass.

Highlights

Plants of Agave spp. perform Crassulacean acid metabolism (CAM) and are highly drought-tolerant, but little is known concerning seed germination under low water availability
Agave species are Crassulacean acid metabolism (CAM) plants distributed throughout a wide variety of environments, a large number of them are found in mesophyte communities [4]; they tolerate high heat and dry conditions and efficiently produce a large biomass in these environments [5], where few commercial crops can grow
Maximum seed water uptake of all Agave species reduced significantly in a non-linear fashion (50% on average) with lower ΨW (Figure 2B) and the large differences observed at −0.03 MPa among species almost disappeared at −1.0 and −1.5 MPa (Figure 1A–C)

Summary

Introduction

Plants of Agave spp. perform Crassulacean acid metabolism (CAM) and are highly drought-tolerant, but little is known concerning seed germination under low water availability. Agave species are Crassulacean acid metabolism (CAM) plants distributed throughout a wide variety of environments, a large number of them are found in mesophyte communities [4]; they tolerate high heat and dry conditions and efficiently produce a large biomass in these environments [5], where few commercial crops can grow. The diversity of Agave species and environments where they are distributed show an array of specific physiological responses associated with the climate where these plants naturally grow. This evidence suggests that agave seed germination, in addition to other physiological processes, might develop properly in conditions which are suboptimal for other species

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