Response of Paris polyphylla var. yunnanensis with different provenances to drought stress

【Objective】 In order to select the drought-tolerant provenances of Paris polyphylla var. yunnanensis, and to provide the theoretical basis for drought-tolerant provenances screening and genetic improvement of germplasm.【Method】 Three provenances of P. polyphylla var. yunnanensis(temperate provenance, south subtropical provenance, and north tropical provenance) were selected as the research materials. The variation of root, stem and leaf traits, biomass distribution and the yield of total saponins under three treatments including sufficient water(W₀), mild drought(W₁) and severe drought(W₂) were studied by using One-way ANOVA, correlation analysis, orthogonal partial least squares-discrimination analysis(OPLS-DA), and variable importance in the projection(VIP) analysis. Meanwhile, the drought resistance of different provenances was evaluated.【Result】 The One-way ANOVA analysis showed that soil moisture significantly affected multiple of above and underground traits of P. polyphylla(P<0.05, the same below). The results showed under drought stress, the fresh weight and biomass of rhizome, fibrous root, stem, and leaf of the P. polyphylla var. yunnanensis in the three provenances decreased. With drought stress intensified, the root mass ratio of temperate provenances was decreased. Meanwhile, the root mass ratio of provenances collected from the south subtropical and the north tropical zones was increased. The provenances collected from the south subtropical zone had the highest value of rhizome biomass(W₀=6.16±2.78 g, W₁=4.78±1.51 g and W₂=2.98±0.59 g) and the yield of saponin(W₀=60.51±28.23 mg, W₁=45.96±16.88 mg and W₂=13.62±2.51 mg) under different soil moisture conditions. Correlation analysis showed that there was extremely significant(P<0.01) positive correlation among plant height, stem thickness, fresh stem weight, stem biomass, fresh leaf weight, leaf biomass, leaf length, and leaf width and fresh weight, biomass and total saponin content of root and rhizome. OPLS-DA showed the values of traits such as rhizome diameter, rhizome length, fibril diameter, fibril length, fibril number, stem fresh weight, stem biomass, leaf fresh weight, leaf biomass, leaf water content, plant height, stem diameter, leaf length, and leaf wide under W₁ were higher than W₂. Based on VIP analysis found that VIP value of plant height, leaf length, leaf width, stem fresh weight, fibril length, fibril number were >1.0. The results suggested that these traits were more sensitive to drought stress.【Conclusion】 Comprehensive analysis of underground organ biomass and total saponin production show that the south subtropical provenance has the strongest drought resistance, traits of high yield and high quality of the provenance should be paid attention to in the future drought-tolerant provenances breeding.