Regulation effects of bioorganic fertilizer on sunflower seedlings growth and leaf physiological indices under salt-alkali stress

A pot experiment was conducted to study the effects of different dosages(0%,2%,4%,and 8%)bioorganic fertilizer on the seed germination,emergence rate,seedling growth,and leaf physiological indices of sunflower under salt-alkali stress.As compared with the control,after 7-28 days under salt-alkali stress(T0),the seed germination rate and emergence rate decreased markedly,seed emergence delayed for 3 days,seedlings shoot-and root length,shoot-and root fresh weight,and leaf chlorophyll and soluble protein contents decreased significantly(P0.05),and the roots were much more sensitive than the shoots.As compared with T0,after the application of 2%(T1),4%(T2),and 8%(T3)bioorganic fertilizer,the seed emergence rate increased by 56.4%(P0.05),64.3%(P0.05),and 85.7%(P0.05),respectively,and the seed emergence advanced by 2-3 days.After 7 days under salt-alkali stress,the seedling growth in treatments T1,T2,and T3 had an obvious increase,leaf chlorophyll content increased by 24.4%(P0.05),27.2%(P0.05),and 33.2%(P0.05),and leaf soluble protein content increased by 34.4%(P0.05),43.6%(P0.05)and 48.8%(P0.05),respectively.When the treated duration prolonged from 7 to 28 days,the inhibitory effects of salt-alkali stress on the seedling growth and the leaf chlorophyll and soluble protein contents in treatments T1,T2,and T3 decreased to some extent.These results indicated that applying 2%-8% bioorganic fertilizer could obviously alleviate the inhibitory effects of salt-alkali stress on the seed emergence,seedling growth,and leaf physiological indices of sunflower.