بررسي اثر ترينگزاپك اتيل و پاكلوبوترازول بر برخي صفات كمي و كيفي چمن Poa pratensis cv Barimpala

Effects of Plant Growth Regulators on Quantitative and Qualitative Response of PoaPratensis Cv Barimpala

Trinexapac-ethyle and paclobutrazol are routinely used to suppress clipping production and may have either positive or negative effects on turfgrass response to drought. Growth inhibition with plant growth regulators (PGRs) has become an important practice in turfgrass management. PGRs modify turfgrass growth by inhibiting either cell division or cell elongation. Phytotoxicity and root reductions have prevented widespread use of cell division inhibitors; therefore, gibberellic acid (GA) inhibitors are more frequently used due to less likelihood of leaf burn and turfgrass injury. The objective of this study was to investigate the effects of exogenous PGRs application on turf performance and physiological activities of Kentucky bluegrass (Poa pratensis cv Barimpala) under various drought treatments. Kentucky bluegrass seeds were planted at 60cm depth in PVC containers of 15cm diameters, filled with sandy-loam soil. The containers received adequate water until PGR application when they were irrigated at 3 different levels (at 2, 5, 10 day intervals). Paclobutrazol and trinexapac-ethyl were applied to separate containers at 0, 400, 600, and 0, 100, 200 gha~l respectively. Trinexapac-ethyl was the PGR that enhanced turfgrass quality during dry down in the natural condition. Application of trinexapac-ethyl not only reduced Kentucky bluegrass clipping production but also was effective in managing turfgrass growth. Paclobutrazol had negligible effects on poa quality and chlorophyll content, but reduced canopy height for up to 3 weeks. Kentuckey bluegrasses treated with any of the PGRs had rooting similar to that in the untreated turf.