Effect Foliar of Proline on Some Physiological Indices of Sugar beet (Beta vulgari L.) to Water Deficit Condition

In order to investigate the growth responses of sugar beet plant to drought stress and foliar application of proline at different growth stages, a field experiment was conducted as split plot arrangement in a randomized complete block design with three replications at the field Research Station of Shahrekord University during 2015. Main plot three level of irrigation treatments (100% (control), 75% and 50% of water requirement) and sub plot three level of proline applied (sprayed with water (control), 5 and 10 mM. The result showed that the drought stress reduced membrane stability index (MSI) and SPAD values and 10 mM proline foliar application causes plant resistance and enhanced MSI and SPAD values under drought stress as compared with the control (sprayed with water). The drought stress reduced leaf area index (LAI), crop growth rate (CGR), net assimilation rate (NAR) and shoot and root dry weights compared with full irrigation. The reduction rate and time in traits were higher on stress level than full irrigation and foliar application of 10 mM were low. There is highly correlation between LAI, CGR and shoot dry weight with root dry weight. So, proline function as compatible solute in osmotic adjustment for sugar beet with the protective role through physiological reactions under drought stress.