title: [Influence of drought on leaf photosynthetic capacity and root growth of soybeans at grain filling stage].
abstract: A drought-resistant soybean cultivar Jinda 70 and a drought-sensitive soybean cultivar Jindou 26 were taken as test materials. At the grain filling stage, the cultivars were subject to three water treatments including sufficient water supply, light drought stress, and severe drought stress by using pot experiments for research on influence of drought on leaf photosynthetic capacity and root growth of soybeans. The results showed that as the degree of drought stress was aggravated, all of the indices including leaf area, chlorophyll content, net photosynthetic rates (Pn), stomatal conductance (g(s)), transpiration rate (Tr), intercellular CO2 concentration (Ci), plant mass, plant height, seed yield, and harvest index in the two cultivars declined. The root length and root mass increased under light drought stress, and decreased under severe drought stress. Root-shoot ratio ascended as the degree of drought stress was aggravated. Under severe drought stress, the increase of root-shoot ratio of the drought-resistant soybean cultivar Jinda 70 was up to 135.7%, which was higher than the that (116.7%) of the drought-sensitive soybean cultivar Jindou 26. Simultaneously, leaf area and chlorophyll content in Jinda 70 were respectively 69.3% and 85.5% of those in the control, which were better than those of Jindou 26. g(s) and Pn of Jinda 70 respectively declined 67.9% and 77.9%, but still lower than those of Jindou 26. Therefore, the decline range of harvest index of Jinda 70 was 43.8%, which was lower than the range of 78.8% of Jindou 26. The Biplot revealed that under different dry treatments, there were significant positive correlations among the six indexes including leaf area, chlorophyll content, Pn, g(s), Tr, and Ci of the two cultivars. There were also significant positive correlations among the six indices including plant mass, plant height, root length, root mass, seed yield, and harvest index. Root-shoot ratio only had significant positive correlation with root mass and had significant negative correlations with other five indices.
authors.forename: Shu-jin
authors.initials: SJ
authors.lastname: Guo
authors.forename: Kai-min
authors.initials: KM
authors.lastname: Yang
authors.forename: Jin
authors.initials: J
authors.lastname: Huo
authors.forename: Yong-hang
authors.initials: YH
authors.lastname: Zhou
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: Wang
authors.forename: Gui-quan
authors.initials: GQ
authors.lastname: Li
mesh_terms: D002734:Chlorophyll / Q000032:analysis; D055864:Droughts; D010788:Photosynthesis; D018515:Plant Leaves / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development*; D012639:Seeds / Q000254:growth & development; D013025:Glycine max / Q000502:physiology*
chemical_list: D002734:Chlorophyll