Abstract:

To study the effect of nitrogen reduction on agronomic traits， photosynthetic characteristics and yield of sesame， Zhengtaizhi 4 was as material and 4 treatments were set including no fertilizer （N0）， nitrogen reduction treatment （75 kg·hm^-2， N1）， routinely nitrogen treatment （150 kg·hm^-2， N2） and high-nitrogen treatment （225 kg·hm^-2， N3）. The leaf photosynthetic characteristics were measured in seedling stage， budding stage， initial flowering stage， full-bloom stage， final flowering stage and maturation stage， and finally agronomic trait， yield and quality indexes were investigated in the harvest period. The results showed that， compared with N2 treatment， N1 treatment did not show significant differences on capsule axis length， I.e.capsules per plant， I.e.seeds per capsule， 1 000-seed weight and yield per plant， while significantly decreased on plant height， and economic coefficient increased by 6.10%. Compared with N2 treatment， the plant height， capsule axis length， I.e.capsules per plant， I.e.seeds per capsule， 1 000-seed weight， yield per plant and economic coefficient of N0 treatment decreased by 15.89%， 12.70%， 25.67%， 6.38%， 10.00%， 40.15% and 16.43%， respectively. The dry matter accumulation showed， compared with N2 treatment， N1 treatment did not show significant differences on dry weight of root， leaf， stem， capsule peel， total matter and seeds capsule ratio of sesame， while N0 treatment decreased significantly on dry weight of root， stem， capsule peel， total matter and seeds capsule ratio of sesame， declined by 19.40%， 25.40%， 28.40 %， 27.57% and 9.83%， respectively. The photosynthetic characteristics indicated that， compared with N2 treatment， N1 treatment did not show significantly differences on net photosynthetic rate （P_n）， transpiration rate （T_r）， water use efficiency （WUE）， stomatal conductance （G_s） and intercellular CO₂ concentration （C_i）， while N0 treatment declined significantly on P_n and WUEby 8.15% and 8.52%， respectively. To sum up， nitrogen reduction had no significant effect on agronomic traits， photosynthetic characteristics and yield of sesame， which provided theoretical basis and technical support for high yield of sesame in the high-nitrogen stubble land.

Key words: sesame, nitrogen reduction, agronomic trait, photosynthetic characteristics, yield

摘要：

为研究减施氮肥对芝麻农艺性状、光合及产量的影响，以郑太芝4号为试验材料，在大田设置不施氮肥（N0）、减施氮肥（75 kg·hm^-2，N1）、常规氮肥（150 kg·hm^-2，N2）和高施氮肥（225 kg·hm^-2，N3）共4个处理，系统研究不同处理下芝麻在苗期、现蕾期、初花期、盛花期、终花期和成熟期植株叶片的光合特性及收获期的农艺性状和产量、品质等。结果表明，与N2处理相比，N1处理的主茎果轴长度、单株蒴数、单蒴粒数、千粒重无显著变化；株高显著下降；单株产量略微增加，但未达到显著水平；经济系数增加6.10%。N0处理的株高、主茎果轴长度、单株蒴数、单蒴粒数、千粒重、单株产量和经济系数较N2分别显著降低15.89%、12.70%、25.67%、6.38%、10.00%、40.15%和16.43 %。从干物质积累来看，N1处理的根干重、叶干重、茎干重、蒴果皮干重、总干物质重和粒蒴比与N2处理差异不显著；N0处理的根干重、茎干重、蒴果皮干重、总干物质和粒蒴比重较N2分别显著降低19.40%、25.40%、28.40%、27.57%和9.83%。从光合特性来看，N1处理的净光合速率（net photosynthetic rate，P_n）、蒸腾速率（transpiration rate，T_r）、水分利用率（water use efficiency， WUE）、气孔导度（stomatal conductance，G_s）和胞间CO₂浓度（intercellular CO₂ concentration，C_i）与N2处理差异不显著；N0处理的P_n和WUE分别较N2处理降低8.15%和8.52%。综上所述，氮肥减施50%对芝麻农艺性状、产量性状及光合特性无显著影响，为芝麻高产、高效栽培提供了理论指导与技术支撑。

关键词: 芝麻, 减施氮肥, 农艺性状, 光合特性, 产量