Effect of natural zeolite and Paclobutrazol on reducing salt stress in KentuckyBluegrass ( Poa pratensis L.)

Salinity is one of the most important factors limiting growth and development of cultivated species. Understanding the possible influence of different soil amendments in saline condition is helpful in selecting soil amendment. Also, application of chemical materials can reduce the salinity problem. Therefore greenhouse experiment was conducted to study the effect of zeolite and drench application of 30 mg paclobutrazol (PBZ) on the salt stress response. Kentucky bluegrass (Poa pratensis) was grown in boxes filled with sand (100%), sand+15% zeolite, sand+30 mg PBZ and sand + 15% zeolite + 30 mg PBZ. Kentucky bluegrass plants were irrigated with 0.24 (control irrigation), 3.4 and 6.4 dS.m-1 salt water daily for 6 months in greenhouse condition to study 1 :) The effect of zeolite, PBZ and their combination on turf quality (TQ), Total fresh and dry weight (TFW, TDW) , Clipping fresh and dry weight (CFW, CDW), Shoot/root ratio, Photosynthetic rate (PR), transpiration, stomatal conductance (SC), Mesophyll efficiency (ME) and water use efficiency (WUE), under different levels of salinity 2:) effect of zeolite, PBZ and their combination on salt deposition, sodium absorption ratio (SAR) and ion compositon in leachate in various salt irrigation. Saline water reduced TQ, TFW, TDW, CY, PR, transpiration, SC, ME, WUE, compared to control. PBZ and salinity reduced growth and development an in cumulative way producing plant that was too small especially at the highest saline concentration. Amendment of sand with zeolite increased TQ, TFW, TDW, CFW, CDW, PR, transpiration, SC, ME and WUE during both the 2nd & 3rd months at both salinity levels. The beneficial effects of zeolite on turf quality and other parameters diminished 3 months after treatments. Amendment of sand with zeolite reduced leaching of Na and K but, increased leaching of Ca and Mg. Using zeolite in medium increased SAR value compared to control. Results indicate that amending with zeolite may buffer soil solution Na concentration in short-term. In the long-term, however, a substantial amount of Na may be retained concurrent with Ca & Mg exchange, thereby increasing sodicity & salinity problems. Also, result indicates PBZ can reduce salinity effect by reducing the availability of saline ion in the medium (greater leaching action).

کلیدواژه ها:

Amendement ، Paclobutazol ، Poa pratensis L. ، Salinity ، Zeolite