Effects Of Water Stress On Endogenous Hormones And Polyamines In Different Tissues Of 'Merlot' Grape

In order to understand the effects of water stress on the accumulation of endogenous poly amines and hormones in different tissues of grape.In this experiment,4-year-old 'Merlot' grape(Vitis vinifera L.cv.Merlot)as the experimental material,the water state of the plant was measured by the predawn leaf water potential,and four water treatments were set up:control(?b?-0.2MPa),mild(-0.2MPa??b?0.4MPa),moderate(-0.4MPa??b?-0.6MPa)and severe(-0.6MPa??b)water stress.The endogenous polyamines and hormones in different tissues(skin,pulp,seed,leaf and root)of grape were quantified by high performance liquid chromatography((HPLC))and ultra high performance liquid chromatography-mass spectrometry(UPLC-MS),respectively.The results are as follows:(1)The matrix temperature and fruit surface light radiation increased under water stress,water stress could affect the physiological metabolism of grape by changing other environmental factors.(2)Water stress could reduce the catabolism 100-grain weight and titratable acid content of berries in ripening berries,but had little effect on titratable acid and the total phenol content during harvest,while long-term water stress accelerated the accumulation rate of soluble solids and anthocyanins,but it could promote the degradation of anthocyanins in the later stage.(3)The accumulation pattern of endogenous polyamines of different tissues of grape was different,and the large accumulation of 3 kinds of polyamines in skin,pulp and seeds after veraison indicates that they may play a role in fruit ripening;water stress can increase the contents of three kinds of polyamines in berry tissues,among which the increase of diamine(Put)is the most obvious;water stress increased the content of Put in leaves,but decreased the contents of Spd and Spm.Water stress decreased the content of Put and Spd in roots,but increased the content of Spm.Under water stress,poly amines in berries and leaves were more inclined to transform to lower amines,while roots tended to transform to polyamines.(4)The accumulation of endogenous hormones in grape varies with different kinds of hormones and tissues.A large amount of iP accumulation in skin during ripening stage indicates that this hormone may be involved in the process of anthocyanin accumulation.Water stress could promote the accumulation of ABA in all tissues,while the contents of IAA,GA3,GA4 and tZ decreased;short-term water stress could promote the accumulation of SA and JA,while long-term water stress could decrease them;the response of iP to water stress was tissue specific,and water stress could significantly promote the accumulation of iP in leaves.To sum up,the accumulation patterns of endogenous hormones and polyamines in grape have strong tissue specificity,and their responses to water stress are also different,and the signal regulatory networks among tissues or organs are both related and independent.Polyamines and iP may play a role in fruit ripening,and their synthesis mechanism and role under water stress need to be further studied.