针对西南喀斯特山区土壤瘠薄制约玉米单产提升的问题,探讨不同耐瘠型玉米光合特性及产量对地力水平的响应,为喀斯特山区耐瘠玉米品种选育、高产抗逆栽培提供理论与技术支撑。本研究以耐瘠型玉米贵卓玉9号(GZY9)和不耐瘠型玉米金贵单3号(JGD3)为试材,选取高(HSF)、低(LSF)两种地力水平田块进行田间试验,研究不同耐瘠型玉米叶面积指数、叶绿素相对含量、气体交换参数、叶绿素荧光特性、叶绿体超微结构、产量及产量构成因素对地力水平的响应。结果表明,与HSF条件相比,LSF条件下2个不同耐瘠型品种叶面积指数、叶绿素相对含量、叶片净光合速率、光化学猝灭系数均显著降低,但耐瘠玉米品种GZY9的降幅小于不耐瘠玉米品种JGD3。LSF条件下,GZY9 蜡熟期至成熟期间的LAI显著高于JGD3,大喇叭口期至乳熟期的SPAD比JGD3高2.11%-19.14%,净光合速率、最大光化学效率和非光化学猝灭系数比JGD3高33.93%、5.14%和9.8%,且乳熟期GZY9叶片叶绿体仍能保持规则、完整形态,基粒数量多且基粒片层、基质片层结构整齐。耐瘠玉米品种GZY9对地力的响应较不敏感,且在LSF条件下仍能保持高产稳产。LSF条件下,GZY9比JGD3的产量增加25.62%,其穗粒数和千粒重则分别增加10.96%和10.50%。可见,相对于不耐瘠型玉米,耐瘠型玉米在LSF条件下可显著提高生育中后期叶面积指数、叶片叶绿素相对含量,改善叶绿体的发育,进而延缓叶片衰老,增强叶片光合能力,增大穗粒数和千粒重,从而实现玉米增产稳产。

Aiming at addressing the issue that poor and thin soil in the karst mountainous areas of Southwest China restricts the improvement of maize yield per unit area, this study explored the responses of photosynthetic characteristics and yield of maize varieties with different poor-soil tolerance to soil fertility levels, so as to provide theoretical and technical support for the breeding of poor-soil tolerant maize varieties and high-yield and stress-resistant cultivation in karst mountainous areas. In this study, poor-soil tolerant maize variety Guizhuoyu 9 (GZY9) and poor-soil sensitive maize variety Jinguidan 3 (JGD3) were used as test materials, and field experiments were carried out in plots with two soil fertility levels, i.e., high soil fertility (HSF) and low soil fertility (LSF). The responses of leaf area index (LAI), relative chlorophyll content, gas exchange parameters, chlorophyll fluorescence characteristics, chloroplast ultrastructure, yield and yield components of maize varieties with different poor-soil tolerance to soil fertility levels were studied. The results showed that compared with the HSF condition, the leaf area index, relative chlorophyll content, net photosynthetic rate of leaves and photochemical quenching coefficient of the two maize varieties with different poor-soil tolerance under the LSF condition decreased significantly, but the decreasing amplitude of the poor-soil tolerant maize variety GZY9 was smaller than that of the poor-soil sensitive maize variety JGD3. Under the LSF condition, the LAI of GZY9 from the waxy stage to the maturity stage was significantly higher than that of JGD3; the SPAD value of GZY9 from the twelve-leaf stage to milk stage was 2.11%-19.14% higher than that of JGD3; the net photosynthetic rate, maximum photochemical efficiency and non-photochemical quenching coefficient of GZY9 were 33.93%, 5.14% and 9.8% higher than those of JGD3, respectively. Moreover, the chloroplasts in the leaves of GZY9 at the milk stage could still maintain a regular and intact shape, with a large number of grana and neat structures of grana lamellae and stroma lamellae. The poor-soil tolerant maize variety GZY9 was less sensitive to soil fertility, and could still maintain high and stable yield under the LSF condition. Under the LSF condition, the yield of GZY9 was 25.62% higher than that of JGD3, and its grain number per ear and 1000-grain weight increased by 10.96% and 10.50%, respectively. It can be seen that compared with the poor-soil sensitive maize variety, the poor-soil tolerant maize variety can significantly increase the leaf area index and relative chlorophyll content of leaves in the middle and late growth stages under the LSF condition, improve the development of chloroplasts, thereby delaying leaf senescence, enhancing the photosynthetic capacity of leaves, increasing the grain number per ear and 1000-grain weight, and ultimately achieving increased and stable maize yield.

S513.01

国家自然科学基金项目（面上项目，重点项目，重大项目）