Application of Plant Growth Regulators on Growth and Physiological Responses of Perennial Ryegrass Under Salinity Stress.

Salinity stress negatively influences plant growth. Turfgrasses are increasingly subjected to salinity stress in many areas due to the acceleration of salinization. Plant growth regulators (PGRs) play essential roles in regulation of plant growth and developmental processes and abiotic stress tolerance. However, growth and physiological responses of turfgrass to salinity stress as affected by PGR application are not well understood. This research was to investigate effects of exogenous application of plant growth regulators on growth and physiological responses of perennial ryegrass exposed to salinity stress. One salinity tolerant and sensitive accession were exposed to 250 mM NaCl for 15 d with or without PGR applications. PGRs were sprayed on plants leave every other day. Application of 6-BA, GABA, SPM, SNP, and BR had higher chlorophyll b content (Chl b) than salinity treatment. JA had positive effects on plant height and Chl b for accession 169. For accession 132, all PGR treatments had significant improvement in leaf water content except for JA. The results indicated that PGRs application had some positive effects on plant growth under the salinity stress. Endogenous hormone content and expression of genes involved in hormone biosynthesis will be measured under salinity stress to reveal molecular mechanisms of PGRs effects on salinity tolerance.