Hydrogen Gas Alleviates Senescence Of Cut Rose Flowers By Antagonizing Ethylene

Rose?Rosa chinensis Jacq.?is one of the four traditional Chinese cut flowers and it has great potential for export in the international market.When cut flowers are harvested,changes in physiological structure will lead to a decline in the vase life and ornamental quality of cut flowers.Therefore,it is very important to keep the freshness of the flowers by using the safe and economic preservation method.Ethylene,as a multiple effect plant hormone,is a key factor influencing the senescence process of cut flowers,especially for the ethylene-sensitive cut flower.Hydrogen gas?H₂?as a signal molecule is not only involved in a variety of growth and development processes in plants,but it is also involved in regulating abiotic stresses.Recent studies have shown that hydrogen gas can delay the ripening and senescence process of fruit and cut flower.However,it has not been reported that the effect of the interaction between hydrogen and ethylene could delay the senescence of the ethylene-sensitive cut rose.This experiment took rose?movie star‘as material,and used hydrogen rich water and ethephon aqueous solution as hydrogen gas and ethylene donors respectively.The aim of the research was to elucidate the effects of exogenous hydrogen gas and ethylene on the life and ornamental quality of the cut rose and their correlations.?1?1,10,50 and 100mg/L ethephon solution could significantly reduce vase life?fresh weight?maximum flower diameter of cut rose,and decrease the ornamental quality of rose.The results suggested that exogenous ethylene accelerates the senescence of?movie star‘of the rose,so the rose?movie star‘is an ethylene sensitive variety.?2?The 1%,10%and 50%concentration of hydrogen rich water treatment significantly increased the vase life,fresh weight,the maximum flower diameter and water balance value of the cut rose,and improved the ornamental quality.Compared with the control?distilled water?,the 100%hydrogen rich water treatment did not prolong the vase life,but also reduced the fresh weight,the maximum flower diameter and water balance value of cut rose,and reduced the ornamental quality.So the low concentration of hydrogen rich water can prolong the vase life enhances the ornamental quality,of which 1%the hydrogen rich water has the best preservation effect.?3?The 1%concentration of hydrogen rich water treatment obviously inhibited the ethylene production of the cut rose,but it did not postpone the peak of ethylene.1%hydrogen rich water significantly reduced the content of 1-aminocyclopropane carboxylic acid?ACC?,1-aminocyclopropane carboxylic synthetase?ACS?and 1-aminocyclopropane carboxylic acid oxidase?ACO?activity,Therefore,exogenous hydrogen gas could delay the senescence of ethylene-sensitive roses by inhibiting the synthesis of endogenous ethylene.?4?The 1%concentration of hydrogen rich water treatment inhibited the expression level of ethylene synthesis genes Rh-ACS3 and Rh-ACO1.At the initiating bloom period and bloom period of cut rose,the 1%concentration of hydrogen rich water treatment up-regulated expression of Rh-ETR1.During the wither period,it down-regulated expression of Rh-ETR3.These results suggested that hydrogen gas can delay the senescence of cut rose by inhibiting the expression level of ethylene synthesis genes and regulating the expression level of ethylene receptor genes.Therefore,1%hydrogen rich water can prolong the vase life and improve the ornamental quality of the cut rose'movie star'by inhibiting the expression level of ethylene synthesis genes and regulating the expression level of ethylene receptor genes.