Resumo

CASTELAN-MUNOZ, Natalia et al. Familial variation in Pinus leiophylla Schiede ex Schltdl. & Cham. seedlings in response to drought: water and osmotic potential. Rev. Chapingo ser. cienc. for. ambient [online]. 2015, vol.21, n.3, pp.295-306. ISSN 2007-4018.  https://doi.org/10.5154/r.rchscfa.2014.10.043.

The seedling variation in four families of Pinus leiophylla with different origins was evaluated regarding the reaction to drought, considering water potential variables (ψ_a), osmotic potential variables (ψ₀), components and biomass allocation. The families of P. leiophylla are located in a seed orchard of the Colegio de Postgraduados in the State of Mexico. The study was done with the purpose of identifying the genotypes resistant to water stress. After 26 days without water, 50 % of the seedlings presented permanent decay in the apex of the stem, with ψ_a = -3.35 MPa and ψ₀ = -3.23 MPa, which represented a decrease of 596 and 112 %, respectively, due to drought. The accumulation of biomass was also significantly affected (P = 0.05) in the families assessed, with the exception of the family from San Rafael. On average, the biomass of the root of the seedlings in drought was 38 % smaller than that of the seedlings under normal circumstances. The P. leiophylla families from San Juan Tetla and Santa María Atepetzingo (both from the state of Puebla) presented a weaker response to the stress imposed, whereas the family from Tlalmanalco (State of Mexico) was the most affected.

Palavras-chave : Water stress; water potential; osmotic potential; biomass allocation.