Abstract: In present study, the primers specific to CmPLDα from chrysanthemum ‘Jinba’ was designed for qRT-PCR analysis of CmPLDα expression profiles in different tissues and in response to abiotic stresses, and exogenous abscisic acid (ABA) and leaf black spot (Alternaria alternata) inoculation, and the roles of CmPLDα in stress responses were disclosed. Result showed that CmPLDα expressed in root, stem, leaf and flower at higher levels in stem, leaf and flower than in the root. Expression of CmPLDα was little affected by cold while generally inhibited by mechanical wound. Heat stress significantly decreased the expression of CmPLDα. Pi deficiency significantly induced the expression of CmPLDα. CmPLDα expression was induced in the late period of salt treatment but induced quickly by ABA treatment. The expression of CmPLDα increased two days after leaf black spot inoculation. It was suggested that expression of CmPLDα was constitutive, and the gene was involved in a variety of physiological processes including temperature stress, Pi deficiency stress, ABAinduced signals and leaf black spot inoculation.

Key words: nutrient release, nitrogen deposition, fine root decomposition, root diameter