追氮量对不同试点小麦旗叶光合特性及产量的影响

为探究小麦在不同地区合理的追氮量,在北京和石家庄2个试点以强筋小麦藁优2018(B₁)和师栾02-1(B₂)为试验材料,设置75 kg·hm^-2(C₁)、105 kg·hm^-2(C₂)、135 kg·hm^-2(C₃)3种追氮水平的大田试验,研究不同追氮量对不同试点小麦光合特性及产量的影响。结果表明,在75~135 kg·hm^-2追氮量范围内,增加追氮量,可提高小麦旗叶净光合速率(Pn),增大气孔导度(Gs)、蒸腾速率(Tr),降低胞间CO₂浓度(Ci)。随着开花后天数的增加,藁优2018的旗叶Pn和Gs下降速度均较师栾02-1快,且Ci升高;随着追氮量的增加,各处理叶绿素(Chl)(a+b)含量均呈增加趋势,开花后14 d,C₂、C₃处理Chl(a+b)含量相对C₁分别平均增加了6.01%和13.81%。籽粒产量、生物产量及收获指数(HI)均随追氮量的增加而提高,平均提高幅度分别为6.235%、3.11%和3.015%。试点间比较表明,两强筋小麦品种的旗叶Chl含量、Pn、Gs、Tr等在北京试点的结果均优于石家庄试点,表明北京试点的环境条件较石家庄试点更有利于小麦旗叶光合性能潜力的发挥,但后者环境更适宜供试品种的生长,更能充分发挥其产量潜力。各光合指标及Chl含量均在追氮量为135 kg·hm^-2(C₃)时最高(旗叶Pn除外),且两品种均获得最高产量,但追氮量为105 kg·hm^-2(C₂)与追氮量为135 kg·hm^-2(C₃)的产量差异不显著,从高产及资源投入角度考虑,强筋小麦藁优2018和师栾02-1的适宜追氮量均为105 kg·hm^-2。本研究结果可为强筋小麦在不同生态区的优质高效生产提供理论与技术参考。

Effects of Topdressing Nitrogen Rate on Photosynthetic Characteristics and Yield of Flag Leaves of Wheat in Different Regions

In order to explore the reasonable amount of nitrogen in wheat,in different regions, Beijing and Shijiazhuang, two strong gluten wheat Gaoyou 2018 and Shiluan 02-1 were as experimental materials and we set three nitrogen uptake rates that are 75 kg·hm^-2, 105 kg·hm^-2 and 135 kg·hm^-2. The effects of topdressing nitrogen on photosynthetic characteristics and yield of flag leaves of wheat was studied through field experiments to provide reference for high-yield and high-efficiency cultivation of wheat. In the range of 75~135 kg·hm^-2 nitrogen application, increasing the amount of nitrogen application could significantly increase the net photosynthetic rate of flag leaves of wheat at flowering stage, increase stomatal conductance and decrease the concentration of carbon dioxide in the intercellular space. With the increase of the number of flowering days, the net photosynthetic rate and stomatal conductance of flag leaf of Gaoyou 2018 decreased faster than Shiluan 02-1, but the intercellular CO₂ concentration increased. With the increase of nitrogen application rate, the content of chlorophyll increased with the increase of nitrogen application rate. At 14 days after flowering, C₂ and C₃ increased by 6.01% and 13.81%, respectively, relative to C₁ treatment. The grain yield, biomass yield and harvest index of two gluten- resistant wheat increased with the increase of N application rate, the average increase was 6.235%, 3.11% and 3.015% respectively. But they differed due to different varieties. Comparing the two strong gluten cultivars selected in this study, the Beijing pilot is more conducive to the display of the photosynthetic performance potential of the flag leaves than the Shijiazhuang pilot, but the Shijiazhuang environment is more suitable for the growth of the tested cultivars and can give fuller play to its production potential. The photosynthetic indexes and chlorophyll content were the highest when the nitrogen topdressing amount was 135 kg·hm^-2 (excluding the net photosynthetic rate of the flag leaf), and the maximum yield was obtained for both varieties. However, the yield difference between 105 kg·hm^-2(C₂)and 135 kg·hm^-2(C₃)was not significant, the suitable topdressing amount of nitrogen for strong gluten wheat Gaoyou 2018 and Shiluan 02-1 is 105 kg·hm^-2. The results of this study can provide theoretical and technical references for high-quality and efficient production of strong gluten wheat in different ecological regions.