Wheeler Raymond M, Fitzpatrick Ann H, Tibbitts Theodore W
NASA Exploration Research and Technology, Kennedy Space Center, Merritt Island, FL, United States.
Horticulture Department, University of Wisconsin, Madison, WI, United States.
Front Plant Sci. 2019 Dec 19;10:1632. doi: 10.3389/fpls.2019.01632. eCollection 2019.
Potatoes ( L.) have been suggested as a candidate crop for future space missions, based on their high yields of nutritious tubers and high harvest index. Three cultivars of potato, cvs. Norland, Russet Burbank, and Denali were grown in walk-in growth rooms at 400 and 800 µmol m s photosynthetic photon flux (PPF), 12-h L/12-h D and 24-h L/0 h D photoperiods, and 350 and 1,000 ppm [CO]. Net photosynthetic rates (P) and stomatal conductance (g) of upper canopy leaves were measured at weekly intervals from 3 through 12 weeks after planting. Increased PPF resulted in increased P rates at both [CO] levels and both photoperiods, but the effect was most pronounced under the 12-h photoperiod. Increased [CO] increased P for both PPFs under the 12-h photoperiod, but decreased P under the 24-h photoperiod. Increased PPF increased g for both [CO] levels and both photoperiods. Increased [CO] decreased g for both PPFs for the 12-h photoperiod, but caused only a slight decrease under the 24-h photoperiod. Leaf P rates were highest with high PPF (800), elevated [CO] (1,000), and a 12-h photoperiod, while growing the plants under continuous (24-h) light resulted in lower leaf photosynthetic rates for all combinations of PPF and [CO]. The responses of leaf photosynthetic rates are generally consistent with prior published data on the plant biomass from these same studies (Wheeler ., Crop Sci. 1991) and suggest that giving more light with a 24-h photoperiod can increase biomass in some cases, but the leaf P and overall photosynthetic efficiency drops.
鉴于土豆（茄属）营养丰富的块茎产量高且收获指数高，已被提议作为未来太空任务的候选作物。三种土豆品种，即诺兰（Norland）、褐皮伯班克（Russet Burbank）和德纳利（Denali），在步入式生长室中种植，光合光子通量（PPF）分别为400和800 μmol m⁻² s⁻¹，光周期为12小时光照/12小时黑暗和24小时光照/0小时黑暗，[CO₂]浓度分别为350和1000 ppm。从种植后第3周到第12周，每周测量一次植株上部冠层叶片的净光合速率（P）和气孔导度（g）。PPF增加导致在两种[CO₂]水平和两种光周期下P速率均增加，但在12小时光周期下这种效应最为明显。在12小时光周期下，[CO₂]增加使两种PPF下的P均增加，但在24小时光周期下P降低。PPF增加使两种[CO₂]水平和两种光周期下的g均增加。在12小时光周期下，[CO₂]增加使两种PPF下的g均降低，但在24小时光周期下仅导致轻微降低。在高PPF（800）、高[CO₂]（1000）和12小时光周期条件下，叶片P速率最高，而在连续（24小时）光照下种植植株，对于PPF和[CO₂]的所有组合，叶片光合速率均较低。叶片光合速率的响应通常与这些相同研究中先前发表的关于植物生物量的数据一致（惠勒等人，《作物科学》，1991年），这表明在某些情况下，采用24小时光周期给予更多光照可增加生物量，但叶片P和总体光合效率会下降。
