Key Lab. Agricultural Engineering in Structure and Environment of Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing 100083, China.
College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China.
J Plant Physiol. 2020 Nov;254:153274. doi: 10.1016/j.jplph.2020.153274. Epub 2020 Sep 6.
Vine cuttings with six to eight unfolded leaves are utilized as is conventional in sweetpotato (Ipomoea batatas (L.) Lam.) seedling production. However, most vine cuttings wilt after transplanting into the field. Moreover, few researchers have examined the influence of photon flux density (PFD) provided by white or white plus red light-emitting diodes (LEDs) on sweetpotato plantlets. In this study, hydroponic sweetpotato (cv. Beniharuka) seedlings using single-node cutting were grown under 20 combinations of five levels of PFDs of 150, 200, 250, 300, and 350 μmol m d and four light qualities: white LEDs with a red light to blue light ratio (R:B ratio) of 0.9, white plus red LEDs with R:B ratios of 1.2 and 2.2, respectively, and fluorescent lamp with an R:B ratio of 1.8 as control, for 20 days under a controlled enviroment. Results showed that the number of newly developed leaves on hydroponic sweetpotato seedlings increased with time in a quadratic function, regardless of light quality. Fluorescent lamps led to greater numbers of new leaves on hydroponic sweetpotato seedlings compared with those grown under LEDs. Plant height, leaf area, and fresh and dry weights increased initially and then decreased with increasing daily light integral (DLI) in quadratic funcitons with a highest value under a PFD of 250 μmol m d. However, no significant differences were observed in fresh and dry weights of hydroponic sweetpotato seedlings grown under PFDs of 200 and 250 μmol m s. The quantum yield of photosystem II (ФPSII) decreased linearly as DLI increased from 8.6-20.2 mol m d. Power consumptions based on fresh and dry weights were lowest in sweetpotato seedlings grown under a PFD of 200 μmol m s provided by white LEDs with an R:B ratio of 0.9. White LEDs also showed higher light energy use efficiency than white plus red LEDs. In summary, it is recommended that a PFD of 200 μmol m s with DLI at 11.5 mol m d provided by white LEDs with an R:B ratio of 0.9 is suitable for hydroponic sweetpotato (cv. Beniharuka) seedling production under a controlled environment.
薯蓣（Ipomoea batatas (L.) Lam.）种苗生产中，通常使用带有 6-8 片展开叶片的薯蓣藤蔓进行扦插。然而，大多数薯蓣藤蔓在移栽到田间后会枯萎。此外，很少有研究人员研究过白光或白光加红光发光二极管（LED）提供的光量子通量密度（PFD）对薯蓣植物的影响。在这项研究中，使用单节扦插的水培甘薯（Beniharuka 品种）幼苗在 20 种 5 个 PFD 水平（150、200、250、300 和 350 μmol m d）和 4 种光质的组合下生长：白光 LED 的红蓝光比（R:B 比）为 0.9，白光加红光 LED 的 R:B 比分别为 1.2 和 2.2，荧光灯的 R:B 比为 1.8 作为对照，在控制环境下进行了 20 天。结果表明，无论光质如何，水培甘薯幼苗上新叶的数量都随时间呈二次函数增加。荧光灯导致水培甘薯幼苗上长出的新叶数量多于 LED 下的新叶数量。植株高度、叶面积和鲜重与干重最初增加，然后随每日光积分（DLI）的增加呈二次函数下降，在 PFD 为 250 μmol m d 时达到最大值。然而，在 PFD 为 200 和 250 μmol m s 下生长的水培甘薯幼苗的鲜重和干重没有显著差异。当 DLI 从 8.6-20.2 mol m d 增加时，光系统 II（ФPSII）的量子产率呈线性下降。基于鲜重和干重的功率消耗在 PFD 为 200 μmol m s 下由白光 LED（R:B 比为 0.9）提供时最低。白光 LED 的光能利用效率也高于白光加红光 LED。总之，建议在受控环境下，使用 PFD 为 200 μmol m s、DLI 为 11.5 mol m d 的白光 LED（R:B 比为 0.9），适合水培甘薯（Beniharuka 品种）幼苗生产。
