Frick J, Nielsen S S, Mitchell C A
National Aeronautics and Space Administration Specialized Center of Research and Training in Bioregenerative Life Support, Purdue University, West Lafayette, IN 47907-1165, USA.
J Am Soc Hortic Sci. 1994 Nov;119(6):1137-43.
Effects of N level (15 to 30 mM), time of N increase (14 to 28 days after planting), and planting density (1163 to 2093 plants/m2) were determined for crop yield responses of dwarf, rapid-cycling brassica (Brassica napus L., CrGC 5-2, Genome: ACaacc). Crops were grown in solid-matrix hydroponic systems and under controlled-environment conditions, including nonsupplemented (ambient) or elevated CO2 concentrations (998 +/- 12 micromoles mol-1). The highest seed yield rate obtained (4.4 g m-2 day-1) occurred with the lowest N level (15 mM) applied at the latest treatment time (day 28). In all trials, CO2 enrichment reduced seed yield rate and harvest index by delaying the onset of flowering and senescence and stimulating vegetative shoot growth. The highest shoot biomass accumulation rate (55.5 g m-2 day-1) occurred with the highest N level (30 mM) applied at the earliest time (day 14). Seed oil content was not significantly affected by CO2 enrichment. Maximum seed oil content (30% to 34%, dry weight basis) was obtained using the lowest N level (15 mM) initiated at the latest treatment time (day 28). In general, an increase in seed oil content was accompanied by a decrease in seed protein. Seed carbohydrate, moisture, and ash contents did not vary significantly in response to experimental treatments. Effects of N level and time of N increase were consistently significant for most crop responses. Planting density was significant only under elevated CO2 conditions.
研究了氮水平（15至30 mM）、增施氮肥时间（种植后14至28天）和种植密度（1163至2093株/m²）对矮生、快速循环型甘蓝型油菜（Brassica napus L., CrGC 5-2，基因组：ACaacc）作物产量响应的影响。作物在固体基质水培系统中生长，并处于可控环境条件下，包括不补充（环境）或升高的二氧化碳浓度（998±12微摩尔/摩尔）。在最晚处理时间（第28天）施用最低氮水平（15 mM）时获得了最高种子产量率（4.4 g m⁻²天⁻¹）。在所有试验中，二氧化碳富集通过延迟开花和衰老的开始并刺激营养枝生长，降低了种子产量率和收获指数。在最早时间（第14天）施用最高氮水平（30 mM）时出现了最高的地上部生物量积累率（55.5 g m⁻²天⁻¹）。种子油含量不受二氧化碳富集的显著影响。使用最晚处理时间（第28天）开始的最低氮水平（15 mM）获得了最大种子油含量（30%至34%，干重基础）。一般来说，种子油含量的增加伴随着种子蛋白质的减少。种子碳水化合物、水分和灰分含量对实验处理的响应没有显著变化。氮水平和增施氮肥时间的影响对大多数作物响应始终具有显著意义。种植密度仅在二氧化碳浓度升高的条件下具有显著意义。
