Chlorophyll, Soluble Sugar and Flower Dry Weight of German Chamomile in Response to Methyl Jasmonate under Salinity Stress

Using plant growth regulators at the stresses environment can improve plant growth and crop production. Hence، in this research response of photosynthesis rate، chlorophyll، soluble sugar and flower dry weight of chamomile to methyl jasmonate under different salinity levels was studied. Values of 0 (control)، 75، 150، 225 and 300μM methyl jasmonate (MeJA) with salinity levels of 2، 6، 10 and 14 dS/m was evaluated as a factorial experiment based on a randomized complete block design with three replications. The effect of MeJA and salinity was significant for photosynthesis rate، leaf temperature difference (T)، relative water content (RWC)، chlorophyll a، chlorophyll b، total chlorophyll، soluble sugar and flower dry weight. Also، MeJA × salinity interaction affected all traits except T. The highest value of photosynthetic rate (9. 99 µmol CO2 m-2 s-1)، chlorophyll a، b and total chlorophyll، in averaging 5. 98، 41. 18 and 45. 10 mg g-1، respectively، and flower dry weight (3. 73 g pot-1) were obtained at 75μM MeJA and 6 dS/m salinity. But، there was no significant difference between 75μM MeJA×6 dS/m and 75μM MeJA×2dS/m for RWC and flower dry weight traits. Maximum soluble sugar was achieved at 75μM MeJA×14 dS/m treatment. In general، using of MeJA increased RWC and decreased undesirable effects of salinity. With decreasing RWC photosynthetic rate، chlorophyll and flower dry weight decreased، but T increased.