论文部分内容阅读
在盆栽条件下,以杂交棉泗杂3号为材料,以花铃期正常灌水[土壤相对含水量(SRWC)(75±5)%]为对照,设花铃期SRWC(60±5)%和SRWC(45±5)%持续干旱50 d两个处理,研究棉铃对位叶气体交换参数和叶绿素荧光参数在持续干旱过程中的动态变化和响应机制.结果表明:SRWC(60±5)%处理0~21 d棉铃对位叶的净光合速率(Pn)、气孔导度(gs)、胞间CO2浓度(Ci)下降,气孔限制值(Ls)上升,叶绿素荧光参数无显著变化,Pn下降的主要原因是气孔限制;处理21~49 d棉铃对位叶Pn持续下降,Ci上升,Ls下降,同时最大光化学效率(Fv/Fm)、实际光化学效率(ΦPSII)和光化学猝灭系数(qP)显著降低,非光化学猝灭系数(NPQ)先升后降,Pn下降的主要原因是非气孔限制;此时叶片PSII系统受到损伤,光合机构及光合酶系统被破坏,同时成铃强度急剧下降,成铃数降低,导致产量下降.SRWC(45±5)%处理0~14 d棉铃对位叶Pn、gs、Ci显著下降,Ls急剧上升,Fv/Fm、ΦPSII、qP无显著变化,Pn下降主要由气孔限制引起;处理14~49 d,棉铃对位叶Pn缓慢下降,Ci上升,Ls下降,Fv/Fm、ΦPSII和qP不断降低,而NPQ先升后降,表明Pn下降主要由非气孔限制引起,同时成铃强度急剧下降,成铃数减少,产量降低.本试验条件下,SRWC(60±5)%和SRWC(45±5)%处理下棉花生长的临界胁迫时间分别为21和14 d.
Under the condition of pot culture, SRWC (60 ± 5)% of hybridization cotton SZZ-3 was used as control, and the normal irrigation at the flowering and rhizosphere stage [soil relative water content (SRWC) And SRWC (45 ± 5)% for 50 days, the dynamic changes and response mechanisms of gas exchange parameters and chlorophyll fluorescence parameters of the boll plants under continuous drought were studied.The results showed that SRWC (60 ± 5)% The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and stomatal limitation (Ls) increased with the increase of leaf photosynthetic rate (Pn) and chlorophyll fluorescence (Pn) (P <0.05). The main reason for this is the stomatal limitation. The Pn of the boll leaves continuously decreased, Ci increased and Ls decreased, and the maximum photochemical efficiency (Fv / Fm), actual photochemical efficiency (ΦPSII) and photochemical quenching coefficient (qP) (NPQ) increased firstly and then decreased. The main cause of Pn decline was non-stomatal limitation. At this time, the PSII system of leaves was damaged, the photosynthetic system and photosynthetic enzyme system were destroyed, and the boll intensity dropped sharply to The number of bolls decreased, which led to the decrease of yield.The Pn, gs, Ci of the flag leaves on the boll of 0 ~ 14 d after treatment with 45% Fv / Fm, ΦPSII and qP did not change significantly. The decrease of Pn was mainly caused by stomatal limitation. From 14 to 49 days after treatment, the Pn of the leaf boll decreased slowly, Ci increased, Ls decreased, Fv / Fm, ΦPSII and qP decreased , While NPQ increased first and then decreased, which indicated that the decrease of Pn was mainly caused by the non-stomatal limitation, and the boll intensity dropped sharply and the number of bolls reduced and the yield decreased. Under the conditions of this experiment, SRWC (60 ± 5)% and SRWC 5)% under the treatment of cotton under the critical stress conditions were 21 and 14 d.