Integrated effect of plant growth regulators with boron sources on some biological parameters of sugar beet

ABSTRACT Any improvement in agricultural systems that results higher production aimed to reduce negative environmental impacts and enhance sustainability plant growth regulators (PGRs) such as gibberellin have similar physiological and biological effects to those of plant hormones, and therefore used widely in agriculture to minimize unwanted shoot growth without lowering plant productivity. An experimental field was conducted at Giza Experimental Station Egypt, on sugar beet plants ( Beta vulgaris L. var. Sara poly) with some plant growth regulators (gibberellin and proline) foliar application at three rates of zero (control), 100 and 200 mg l −1 and boron sources (Boric acid and B-NPs) with 75% of macro-nutrients from full dose. The main target of this study to evaluate another plant growth regulator source like proline which is safer than gibberellin for maximizing sugar beet biological parameters to reduce the gap between sugar consumption and production in presence of boron sources. Data showed that the foliar applications of gibberellin (GA 3 ) at rate 100 mg l −1 and proline at 200 mg l −1 were found to be the more effective without significant differences for plant growth, productivity and quality may be due to increased N use efficiency, especially at sub-optimal macro nutrient fertilizers. Regard to boron sources, B-NPs had positive effect on all biological parameters under study due to sugar transport, cell membrane synthesis, nitrogen fixation, respiration, carbohydrate metabolisms, root growth, functional characteristics and development.