biologia plantarum

Biologia plantarum 60:555-562, 2016 | DOI: 10.1007/s10535-016-0623-5

Effect of exogenous abscisic acid on cold acclimation in two Magnolia species

Y. Yang¹, N. Yao², Z. K. Jia², J. Duan³, F. J. Chen⁴, Z. Y. Sang⁵, L. Y. Ma^2,*

¹ Forestry Department, Beijing University of Agriculture, Beijing, P.R. China

² Laboratory for Silviculture and Conservation, Beijing Forestry University, Beijing, P.R. China

³ National Energy R&D Center for Non-food Biomass, Beijing Forestry University, Beijing, P.R. China

⁴ Biotechnology Research Center, Three Gorges University, Yichang, Hubei Province, P.R. China

⁵ Forestry Bureau of Wufeng County, Wufeng, Hubei Province, P.R. China

In northern China, freezing injury is observed frequently in the rare species Magnolia wufengensis but not in the more common species Magnolia denudata. To investigate the role of the phytohormone abscisic acid (ABA) on frost tolerance in these two species, exogenous ABA was applied to the seedlings and then physiological and biochemical responses were measured during cold acclimation. Shoot growth cessation was stimulated by ABA in M. wufengensis but not in M. denudata. Abscisic acid inhibited shoot growth in M. wufengensis but not in M. denudata. Treatment with ABA stimulated leaf senescence in both species, and this effect was greater in M. denudata. For both species, ABA-treated plants exhibited bud dormancy sooner and had an increased tolerance to freezing, decreased water content and increased accumulation of proline, glucose, and fructose in shoots. These effects were generally greater for M. denudata. Freezing tolerance was significantly correlated with content of water, proline, glucose, and fructose for both species, but freezing tolerance was significantly correlated with raffinose content only in M. wufengensis. We conclude that exogenous ABA could increase cold acclimation and improve cold hardiness of both Magnolia species, although M. denudata was more responsive to ABA than M. wufengensis, which might result from a greater dehydration and accumulation of proline and certain soluble sugars.

Keywords: freezing tolerance; Magnolia denudata; M. wufengensis; proline; soluble sugar

Subjects: abscisic acid; cold stress; cold acclimation; freezing tolerance; proline; soluble sugars

Received: May 8, 2015; Revised: December 1, 2015; Accepted: December 8, 2015; Published: September 1, 2016  Show citation