Inhibitory Effects of Jasmonic Acid and its Analogues on Barley (Hordeum vulgare L.) Anther Extrusion

Plant hormones play many important roles in plant growth and development. We previously tried to control barley (Hordeum vulgare L.) flowering in ear cultures treated with plant hormones and related compounds, and found that anther extrusion from florets was reduced by treatment with 100 ppm methyl jasmonate (MJA). In the present study, we show that 10 ppm MJA also inhibits anther extrusion in barley ear cultures. Spraying field-grown barley ears with MJA clarified the efficacy of this chemical under field conditions, but higher concentrations (100 to 1000 ppm MJA) were required. In addition, we investigated the activity of jasmonic acid (JA) analogues and cucurbic acid analogues in barley ear cultures. Some esters of JA showed similar effects to that of MJA, but effects of 9,10-dihydrojasmonic acid (DJA) and cucurbic acid derivatives were lower than that of MJA. In light of these data, we discuss the structural requirements for increased inhibition of barley anther extrusion.