Effects Of Different Water Stress Intensity On Nitrogen Absorption And Metabolism In The Grape(‘Cabernet Sauvignon’) Young Plants

Grape plant is known to be sensitive to water stress(WS), and responsing to different water stress intensity(DWSI), stress time(ST) by changing nitrogen(N) uptake, N absorption forms, absorption ratio, etc. This study investigated the effects of DWSI(non-stress: CK; light stress: T1; moderate stress: T2; severe stress: T3), simulated by four levels of Polyethylene glycol 6000(PEG6000)(0%, 5%, 10%, 15%, w/v) under nutrient solution culture condition(NSCC), on N uptake(NU), soluble protein content(SPC), N metabolism-related enzyme activity(NMEA), content of Polyamines(PAs) and 20 amino acids(AAs) of different tissues of Vitis vinifera L. cv. Cabernet Sauvignon. The results are as follows:(1) Compared to CK, N content of dry matter, SPC, KEA of different tissues in T1, T2, T3 were significantly changed, and the greater the stress intensity, the more significant these indexes transformed. Light water stress enhanced NU and AU, but in different ways. NU peak came ahead of time, and AU peak significantly increased. However, NU and AU were significantly declined in T2, T3. Besides, the absorption ratio of NU/AU fluctuated in CK.And compared to CK, the ratio significantly declined.(2) PAs, which severely and frequently changed with increased stress levels, showed tissue-specific and time-specific features. And Spd content dominated in the total free PA content.(3) Analysis results of concentration of free AA, under different treatments, was as followed: ① Compared to CK, the total concentration of 20 free AAs was substantially changed under different treatments, which was not the case among treatments in the same organ. It was not significant among water stress treatments in the same organ(P<0.05).② AA fingerprints existed in different treatments and in different organs. Even if fingerprint information was similar in different treatments and organs, every single AA showed differentially in proportion and weights. ③ Difference of AA in organs influenced mutually,and correlated significantly in pairwise caparisons. ④ Free AA in grape organs responsed integrally but worked partially. ⑤ Physiology processes of differential AAs were accordance with the results of database analysis.