The development of the aquatic -like roots of three foliage plants Pachira macrocarpa, Dracaena deremensis 'Corapacta' and Agave americana and the effects of different concentrations of a-Naphthaleneacetic acid (NAA) on rooting were investigated as potted in hydroculture. The results showed that three foliage plants initiated the roots at 9.7, 14.4 and 3.5 d respectively hydroculture on and reached the peak of rooting at 40* day, while P. Macrocarpe produced the most of roots to the first 20 d of the hydroculture. The root of A. Americana stopped increasing in length at about 20 d of the hydroculture, but the roots of other two plants kept growing as hydroculture continued. The maximum root diameters were measured at 20 d for P. Macrocarpaand A. Americana and at 40 d for D. Deremensis 'Compacta'. However, The Root of three plants were found to shrink in diameter after 20 d or 40 d. NAA treatment with the concentrations of 100、 200 and 300 mg/L increased root number significantly and the optimal concentration was 200 mg/L for three plants. NAA treatments delayed the root formation of P. Macrocarpa and A. Americana and decreased root growth velocity. Compared to the control the aquatic-like roots of three plants with NAA treatments were shorter in length and bigger in diameter.%研究发财树、螺纹铁和龙舌兰3种观叶植物水培中水生性根系发生与生长特性、NAA的诱导效应.结果表明,3种植物分别在水培后的第9.7、14.4和3.5 d开始出根,40 d左右发根数达到最高峰,其中发财树在水培后的前20d就产生大部分根系.龙舌兰的根在20d左右就达最长,其它2种植物根的生长随时间延长而增长.发财树、龙舌兰培养到20 d,螺纹铁培养到40 d,水生性根的基部粗度达到最大,但之后3种植物水生性根系基部径粗均会出现不同程度的缩小.不同浓度NAA(100、200和300mg/L)处理可提高3种植物根系产生的数量,以200mg/L NAA处理产生的根数最多；NAA处理会延迟发财树、龙舌兰的出根时间；降低根生长速率,处理后的根长较对照短,根系更加粗壮.
展开▼
