Exogenous Glycinebetaine and Salicylic Acid Application Improves Water Relations, Allometry and Quality of Hybrid Sunflower under Water Deficit Conditions

Abstract

Limited water availability hampers the sustainability of crop production. Exogenous application of glycinebetaine (GB) and salicylic acid (SA) has been found very effective in reducing the adverse effects of water scarcity. This study was conducted to examine the possible role of exogenous GB and SA application in improving the growth and water relations of hybrid sunflower (Helianthus annuus L.) under different irrigation regimes. There were three levels of irrigation, viz. control (normal irrigations), water stress at budding stage (irrigation missing at budding stage) and water stress at flowering stage (FS) (irrigation missing at FS). GB and SA were applied exogenously at 100 and 0.724 mm respectively, each at the budding and FS. Control plants did not receive application of GB and SA. Water stress reduced the leaf area index (LAI), leaf area duration (LAD), crop growth rate (CGR), leaf relative water contents, water potential, osmotic potential, turgor pressure, achene yield and water use efficiency. Nevertheless, exogenous GB and SA application appreciably improved these attributes under water stress. However, exogenous GB application at the FS was more effective than other treatments. Net assimilation rate was not affected by water stress as well as application of GB and SA. The protein contents were considerably increased by water stress at different growth stages, but were reduced by exogenous GB and SA application. The effects of water stress and foliar application of GB were more pronounced when applied at FS than at the budding stage. Moreover, exogenous GB application was only advantageous under stress conditions.

Gas exchange and chlorophyll synthesis of maize cultivars are enhanced by exogenously-applied glycinebetaine under drought conditions

“…The GB-induced drought tolerance could be attributed to lowering of the osmotic potential due to net solute accumulation in response to water stress, which might help to preserve the metabolic processes, contribute to growth of plants through maintaining turgor in cells (Chimenti et al 2002), and ultimately increase drought tolerance. These results are in agreement with Hussain et al (2009) who reported that exogenous application of GB improved the growth in sunflower under drought. Legend: Same as Table 1 Assimilation and partitioning of assimilates during grain development are of vital value.…”

“…GB-treatment alleviated the detrimental effects of drought stress with subsequent increases in yield and yield related parameters both under stress and under non-stress conditions. The improvement in yield by GB-treatment is in line with Diaz-Zarita et al (2001) and Hussain et al (2009), who reported that GB-treatment enhanced the yield of water stressed wheat and sunflower plants.…”

“…At present, with the aim of improving agricultural yield within the limited water resources, it is imperative to develop crops able to produce a high yield when growing in stressed environments. It is known that endogenous GB acts and an osmoprotectant in cells under water stress conditions (Hussain et al 2009). It is also important to know the role that the exogenously-applied GB plays in drought resistance of crops.…”

The Evaluation of Exogenous Application of Salicylic Acid on Physiological Characteristics, Proline and Essential Oil Content of Chamomile (Matricaria chamomilla L.) under Normal and Heat Stress Conditions

“…Razmjoo et al (2008) indicated that drought stress caused a significant reduction in the plant height of chamomile [15]. The reduction in plant height seems to be the result of disturbed plant water relations, in particular the turgor potential [36]. This means that reduced water uptake results in a decrease in the tissue water contents and turgor.…”

Saving Water in Arid and Semi-Arid Countries as a Result of Optimising Crop Evapotranspiration

“…Recently, rapid and economically feasible approaches have been proposed to counteract yield losses and water use efficiency (WUE) decreases under deficit irrigation strategies. Several studies have emphasized that osmotic adjustment, which is achieved by exogenous application of osmoprotectants, is a useful approach for improving crop and water productivity under deficit irrigation (Agboma et al, 1997;Hussain et al, 2009). Of the different compatible solutes known, glycinebetaine (GB) is relatively more important as it is capable of promoting yields and WUE under water deficit.…”