低温胁迫对不同基因型小麦生理生化特性的影响-作物栽培学与耕作学专业论文.docxVIP

PAGE PAGE III Abstract The experiments were conducted at Dayangdian test base of Anhui Agricultural Uniwersity in 2011-2013. The effects of low temperature stress on cell structure of leaf and tillering node, photosynthetic performance of leaf, endogenous protective enzyme system and endogenous hormones of leaf and root were studied among different wheat genotypes (spring wheat cultivars: yangmai 18 and huaimai 30, semi-spring wheat cultivar: zhengmai 9023, and semi-winter wheat cultivar: yannong 19) at tillering and elongation stages. The main results were as follows: Effects of low temperature stress on penultimate cell structure of different wheat genotypes at tillering and elongation stages The mesophyll cells of three wheat genotypes after the seedlings were exposed to low temperature stress at tillering and elongation stages were different dgree of contraction, and intercellular space of them increased. At tillering stage, the arrangement of the mesophyll cells of spring wheat cultivar (huaimai 30) and semi-spring cultivar (zhengmai 9023) were more irregular than semi-winter wheat cultivar (yannong 19), while the vessel and sieve tube of huaimai 30 tillering node ruptured after low temperature stress. At elongation stage, the dgree of cell contraction of spring wheat cultivar (huaimai 30) was more obvious than that of other cultivars. Effects of low temperature stress on photosynthetic performance of different wheat genotypes at tillering and elongation stages Tthe photosynthetic parameters which contained net photosynthetic rate (Pn), stomata conductance (Gs) and intercellular CO2 concentratio (Ci), and chlorophyll fluorescence parameters which contained minimal fluorescence (Fo), maximum quantum yield of PSII (Fv/Fm), photochemical quenching (qP), non-photochemical quenching coefficient (NPQ) and acyclic photosynthetic electron transfer rate of PSII (ETR) were all significant differences among three wheat genotypes after the seedlings were exposed to low