Abstract: 【Objective】 The study aims to clarify the response mechanism in physiological characteristics as well as dry matter accumulation and distribution to drought of cotton varieties with different drought resistance in the hope of providing theoretical basis for stress-resistant cultivation and drought-tolerant variety breeding of cotton. 【Method】 Xinluzao 17 (drought sensitive variety) and Xinluzao 22 (drought-tolerant variety) were used as materials and conventional irrigation (4,500 m³/hm², CK), mild drought (2,700 m³/hm², W1) and moderate drought (900 m³/hm², W2) were set for water treatment under the conditions of soil column cultivation. The changes of leaf area, chlorophyll content, gas exchange parameters, chlorophyll fluorescence parameters and dry matter accumulation and distribution during the stages of yield formation were determined. 【Result】 Leaf area, chlorophyll a content (Chl a), chlorophyll b content (Chl b), total chlorophyll content (Chl), net photosynthetic rate (Pn), stomatal conductance (gs), intercellular carbon dioxide concentration (Ci) and transpiration rate (Tr) decreased significantly with the increase of drought stress, and the performance of the variety was that the decline of Xinluzao 22 was smaller than that of Xinluzao 17. Compared with CK, the maximum photochemical efficiency (Fv/Fm) of the two cotton varieties treated by W1 was not significantly reduced, but the actual photochemical efficiency [Y(II)] and photochemical quenching coefficient (qP) of Xinluzao 17 were inhibited. The non-photochemical quenching coefficient (NPQ) was significantly increased during the mild and moderate drought stress. The dry matter of reproductive organs and vegetative organs at the boll opening stage of Xinluzao 17 treated by W1 were 30.44% and 16.61% lower than CK, respectively. However, Xinluzao 22 was only 12.50% and 5.74% lower than CK, respectively. In addition, the root to shoot ratio of Xinluzao 22 was 2.54%, 9.56% and 14.48% higher than that of Xinluohao 17 treated by CK, W1 and W2 at the full boll stage. 【Conclusion】 Xinluzao 22, a cotton variety with strong drought tolerance, maintains better photosynthetic performance and larger root-shoot ratio to guarantee the accumulation of dry matter of the reproductive organs to adapt to drought stress.

Key words: cotton; drought stress; photosynthetic characteristics; dry matter accumulation

摘要： 【目的】 研究抗旱性不同的棉花品种叶片光合生理特性及干物质累积与分配对干旱的响应机制,为棉花抗逆栽培和耐旱性品种选育提供理论依据。【方法】 在土柱栽培的条件下,以棉花品种新陆早17号(敏旱型)和新陆早22号(耐旱型)为材料,设常规灌溉(4 500 m³/hm²,CK)、轻度干旱(2 700 m³/hm²,W1)和中度干旱(900 m³/hm²,W2)水分处理,测定棉花产量形成期叶面积、叶绿素含量、气体交换参数、叶绿素荧光参数和干物质累积与分配的变化。【结果】 2个棉花品种的叶面积、叶绿素a含量(Chl a)、叶绿素b含量(Chl b)、叶绿素总含量(Chl)、净光合速率(Pn)、气孔导度(gs)、胞间二氧化碳浓度(Ci)、蒸腾速率(Tr)均随干旱胁迫程度的增加显著降低,品种间以新陆早22号降幅较小。与CK相比,W1条件下2棉花品种的最大光化学效率(Fv/Fm)并未显著降低,但新陆早17号的实际光化学效率[Y(II)]和光化学猝灭系数(qP)受到抑制,且轻度和中度干旱下非光化学淬灭系数(NPQ)在盛铃期显著增加。在W1条件下,新陆早17号吐絮期的生殖器官和营养器官干物质分别比CK下降了30.44%和16.61%,新陆早22号仅下降12.50%和5.74%。CK、W1、W2条件下,新陆早22号的根冠比在盛铃期较新陆早17号高2.54%、9.56%和14.48%。【结论】 耐旱性较强的棉花品种新陆早22号通过保持更好的光合性能和较大的根冠比,来保持生殖器官干物质的累积以适应干旱胁迫。

关键词: 棉花, 干旱胁迫, 光合特性, 干物质累积