开放式空气二氧化碳浓度增高对小麦产量形成的影响

利用农田开放式空气CO₂浓度增高(FACE)系统平台，以弱筋小麦宁麦9号为供试品种，研究大气CO₂浓度增高和不同施氮水平对小麦生育期、株高、产量和产量构成因素的影响.结果表明：FACE处理的小麦播种至抽穗期、抽穗至成熟期及全生育期天数分别比对照缩短1.3、1.3和2.6 d，但均未达到显著水平；FACE处理的小麦穗长、穗下第1和第2节间长度显著变长，成熟期株高显著增加，比对照增加4.0%；低、中、高氮条件下，FACE处理小麦的籽粒产量分别比对照提高15.2%、21.4%和35.4%，平均增产24.6%，均达极显著水平；FACE处理小麦的单位面积穗数极显著增加，比对照增加17.8%，使穗粒数和粒重显著增加，分别比对照增加了2.9%和4.8%.FACE处理使小麦显著增产主要是由于单位面积穗数显著增加，而单位面积穗数的增加主要是由于小麦的分蘖能力明显增强所致.

Effects of free-air CO2 enrichment (FACE) on yield formation of wheat

To investigate the effects of predicted higher CO₂ levels on the growth duration, plant height, yield, and yield components of wheat (Triticum aestivum L.), a free-air CO₂ enrichment (FACE) experiment with weak gluten variety Ningmai 9 was conducted at Anzhen of Wuxi in Jiang-su Province in 2001-2002 and 2002-2003 growth seasons. The target ［CO₂］ in FACE plots was 200 μl·L^-1 above that in ambient air. Three levels of N were supplied, i . e., 90 kg·hm^-2 (2001-2002) and 125 kg·hm^-2 (2002-2003) (low level, LN), 180 kg·hm^-2(2002-2003) (medium level, MN), and 250 kg·hm^-2 (high level, HN).The durations from sowing to heading and from heading to maturity and the whole growth period of wheat in FACE plots shortened 1.3, 1.3 and 2.6 days, respectively, compared with the control. FACE increased the plant height (+4.0%) significantly, due to the increases of panicle length and of the first and second internode lengths. FACE also greatly increased the grain yield by an average of 24.6%. Across the two years, there was a positive ［CO₂］×N interaction for grain yield, with a yield increase of 15.2%, 21.4% and 35.4% at LN, MN and HN, respectively. The ears per square meter in FACE plots was increased by an average of 17.8%, mainly due to the increase of maximum tiller number per unit ground area rather than that of the percentage of productive tiller (panicle bearing). In addition,FACE increased the grain number per ear(+2.9%)and the individual grain mass (+4.8%).