Identification and seasonal variation of water metabolism with wild grapes (Vitis) in Guizhou province

Abstract:【Objective】In order to identify the water metabolism characteristics and seasonal variation pattern of wild Vitis resources in Karst environment, the present experiment was undertaken. Besides, the results was expected to promote the development and utilization of new Vitis varieties with drought resistance as well as the revealment of plant drought resistance mechanism in Karst area.【Methods】In this study, 7 kinds of wild Vitis resources including 22 genotypes from Guizhou province were selected as the testing materials. Additional 2 kinds of Vitis, V. vinifera L.‘Red Globe’and V. vinifera L.×V. la- brusca L‘. Crystal’, were cultivars widely planted in Guizhou province, which were selected as the con- trast (CK). The field identification method was adopted to measure the water metabolism characteristics of sample materials in mid-May, mid-July and mid-September in 2019. The middle cane and leaf of the plant were taken as the testing objects, and they were then washed by the improved“washing method”(the washing liquid was oxalic acid solution). After that, the comprehensive statistical method, member- ship function method, variance analysis method, principal component analysis and pearson coefficient method were adopted to evaluate the water metabolism characteristics of wild Vitis resources. The SPSS 21.0 and Excel were used to calculate statistically the specific data.【Results】The results of specific con- ductivity of cane (KS), leaf-specific hydraulic conductivity (LSC), leaf water potential (LWP), water conductivity (KH) and huber value (Hv) of wild Vitis resources in Guizhou province indicated that, theVitis quinquangularis Rehd. showed the best performance, the V. flexuosa Thunb., V. davidii Foëx. andV. bellula (Rehd.) W. T. Wang. ranked second, next were the V. adenoclada Hand-Mazz. and V. wilsonaeVeitch, and the V. pseudoreticulata W. T. Wang. was the worst among the 7 kinds of wild Vitis grapes  but superior to the foreign population. Compared to the 22 genotypes, the water metabolism characteris- tics of Vitis quinquangularis Rehd.‘HX-9’was excellent, V. bellula (Rehd.) W. T. Wang.‘ML-5’,‘ML-11’, V. flexuosa Thunb‘XS-4’, V. davidii Foëx.‘ZQ’and V. adenoclada Hand-Mazz.‘ML-11’performed well, Vitis quinquangularis Rehd.‘GL-1’,‘XQK-1’and V. wilsonae Veitch‘DP-1’per- formed poorly, and the remaining testing materials performed generally. The leaves of Vitis quinquangu- laris Rehd. had a stable and efficient water use mechanism, and‘HX-9’could be used as the germ- plasm resources for further research and utilization. The difference in water metabolism characteristics among various populations was due to the genetic specificity, and the reason for difference among popu- lations was associated with the different habitats on genotype of vegetative organs. The water metabo- lism indexes of various wild Vitis groups tended to be different in their water metabolic mechanism. TheVitis quinquangularis Rehd. was KS and LSC; the V. davidii Foëx., V. bellula (Rehd.) W. T. Wang and V. flexuosa Thunb. were Hv and LSC; the V. adenoclada Hand-Mazz. was KH and LWP; the V. wilsonaeVeitch was Hv and KH; and the V. pseudoreticulata W. T. Wang was LSC and LWP. The seasonal varia- tion of LWP, KH, KS, Hv and other parameters of wild grapes showed that they were the highest in July (summer), then next was in the May (alternative spring or summer), and the lowest was in September (autumn). The seasonal variation of LSC and water metabolism parameters of V. pseudoreticulata W. T. Wang showed they were the highest in May (alternative spring or summer), the middle in July (sum- mer), and the lowest was in September (autumn). The correlation analysis showed that the characteristic values of the water metabolism of wild grapes were closely related to the environmental factors. The monthly average temperature, monthly precipitation and KH, KS, LWP, Hv were significantly or very significantly and positively correlated. The monthly average relative humidity and Hv were very signifi- cantly positively correlative. Among the characteristics correlation of water metabolism, the LSC was little affected by environmental factors and had little correlation with cane parameters, and the KH, KS, LWP and Hv had a stronger correlation. KS and LWP had significantly negative correlation, and the rest had significant correlation among characteristic values.【Conclusion】There were some differences in the water metabolism characteristics of population of wild Vitis resources in Karst environment in Gui- zhou province, and the Vitis quinquangularis Rehd. showed the best performance. The water metabolo- ism characteristics of wild Vitis varied with different seasons. In the season with high temperature and abundant rainfall, the ability of water metabolism was higher and showed the best in July (summer). The monthly precipitation and average temperature were the direct factors that caused the change of wa- ter metabolism characteristics of wild Vitis grapes. Because‘HX-9’(Vitis quinquangularis Rehd.) had the excellent capacity of using water in leaf and water transport mechanism cane, it can be used as one of the drought resistant Vitis resources to develop and utilize.