Increasing Drought Resistance of two Ground Cover Species by Spraying Trinexapac-Ethyl

Nowadays with global warming and reduced rainfall and groundwater sources used to supply water to the green space is one of the most important problems facing today s society. Therefore, in this research to reduce water consumption and increase drought tolerance in wheat cover ground kidney weed (Dichondra repens L.) and creeping jenny (Lysimachia nummularia L.) the growth regulator trinexapac-ethyl was used. The factorial experiment was conducted in a randomized complete block design with three factors including two species of cover plants, four levels of trinexapac-ethyl (control, 50, 100 and 200 g ha-1), four levels of soil moisture (irrigation in the suction of 20-25 (control), 30-35, 50-55, and 70-75 centibar (cb)) and three replication at the research greenhouse of the University of Guilan in 2015. Results showed that drought stress and TE treatment has significant effects on shoot length of two species studied. Drought stress significantly increased the amount of electrolyte leakage (EL), but spraying with TE decreased EL under drought stress. Amount of relative water content (RWC) of leaves decreased with increasing soil moisture suction, in both species, but spraying with different concentration of TE, not only prevented reducing the amount of relative RWC of leaves but also prevented the degradation of chlorophyll under stress condition. In general, based on the results TE can be used to reduce water use in cover crops and to increase their drought tolerance.