title: Grafting of Cucumis sativus onto Cucurbita ficifolia leads to improved plant growth, increased light utilization and reduced accumulation of reactive oxygen species in chilled plants.
abstract: The effects of chilling at 14 and 7 degrees C on plant growth, CO(2) assimilation, light allocation, photosynthetic electron flux and antioxidant metabolism were examined in cucumber (Cucumis sativus L. cv. Jinyan No. 4, CS) plants with figleaf gourd (Cucurbita ficifolia Bouché, CF) and cucumber as rootstocks, respectively. Growth inhibition by chilling at 7 degrees C was characterized by irreversible inhibition of CO(2) assimilation in grafted plants with cucumber as rootstock and scion (CS/CS) but this effect was significantly alleviated by grafting onto CF roots (CS/CF). Chilled CS/CF plants exhibited a higher photosynthetic activity and lower proportion of energy dissipation than chilled CS/CS plants. Chilling resulted in a greater decrease in the electron flux in photosystem (PS) II (J (PSII)) than the rate of energy dissipation either via light-dependent (J (NPQ)) or via constitutive thermal dissipation and fluorescence (J (f,D)) in CS/CS plants. In parallel with the reduction in J (PSII), electron flux to oxygenation (J (o)) and carboxylation by Rubisco (J (c)) all decreased significantly whilst alternative electron flux in PS II (J (a)) increased, especially in CS/CS plants. Moreover, CS/CF plants exhibited higher activity of antioxidant enzymes, lower antioxidant content and less membrane peroxidation relative to CS/CS plants after chilling.
authors.affiliation: Department of Horticulture, Zhejiang University, Kaixuan Road 268, 310029 Hangzhou, People's Republic of China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.forename: Lifeng
authors.initials: L
authors.lastname: Huang
authors.forename: Xiaotao
authors.initials: X
authors.lastname: Ding
authors.forename: Kai
authors.initials: K
authors.lastname: Shi
authors.forename: Jingquan
authors.initials: J
authors.lastname: Yu
mesh_terms: D000042:Absorption; D000975:Antioxidants / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D018553:Cucumis sativus / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D028464:Cucurbita / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D004583:Electrons; D016166:Free Radical Scavengers / Q000378:metabolism; D005615:Freezing; D008027:Light; D055668:Photochemical Processes / Q000528:radiation effects; D017785:Photons; D010788:Photosynthesis / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism / Q000528:radiation effects; D018517:Plant Roots / Q000201:enzymology / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013312:Stress, Physiological / Q000528:radiation effects; D046509:Tissue Culture Techniques / Q000379:methods*; D014867:Water / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D045332:Photosystem II Protein Complex; D017382:Reactive Oxygen Species; D014867:Water; D002734:Chlorophyll; D002245:Carbon Dioxide