BACKGROUND Haworthia are desert succulents belonging to the Asphodelaceae family. Haworthia species are cultivated commercially as ornamentals and some rare species are quite valuable at retail market but growth slowly and difficult to propagation. However, an efficient micropropagation protocol was remained insufficient. RESULTS The organogenic cultures obtained from inflorescence explants were cultured on Murashige and Skoog (MS) medium supplemented with various combinations of 6-benzylaminopurine (BA) and α-naphthalene acetic acid (NAA) under a light intensity of 10 μmol m-2 s-1 or 45 μmol m-2 s-1. The highest callus proliferation index (93.15%) with 1.0 mg L-1 BA + 0.1 mg L-1 NAA under a light intensity of 10 μmol m-2 s-1. The best shoot proliferation rates were on media with either 1 mg L-1 BA + 0-0.4 mg L-1 NAA (65.57-81.01%) under a light intensity of 45 μmol m-2 s-1. The highest root length (15.57 mm) and the highest rooting frequency (17 roots per shoot) were obtained when adventitious shoots were inoculated on MS medium with 0.4 mg L-1 NAA + 0.4 mg L-1 IBA. The survival rate of the transplanted plantlets was about 100%. The efficient micropropagation protocol proliferated Haworthia regenerate plants from inflorescence within 11 weeks. CONCLUSIONS The present study determined the best combination of light intensity and plant growth regulators (PGRs) for improved organogenesis of Haworthia during propagation by tissue culture. This optimized protocol showed light intensity is an important factor for efficient callus or shoot regeneration. These results indicate that it will be useful to optimize the light conditions for future commercial cultivation, germplasm conservation, genetic engineering and molecular biology research of this ornamental plant.

中文翻译：

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光强和植物生长调节剂对观赏多肉植物Haworthia愈伤组织增殖和枝条再生的影响。

背景Haworthia是属于Aphodelaceae科的沙漠多肉植物。Haworthia物种作为观赏植物进行商业种植，一些稀有物种在零售市场上非常有价值，但生长缓慢且难以繁殖。但是，有效的微繁协议仍然不够。结果从花序外植体获得的器官发生培养物在10μmolm-2 s-的光强度下在补充了6-苄基氨基嘌呤（BA）和α-萘乙酸（NAA）各种组合的Murashige和Skoog（MS）培养基上进行培养。 1或45μmolm-2 s-1。在10μmolm-2 s-1的光强度下，1.0 mg L-1 BA + 0.1 mg L-1 NAA具有最高的愈伤组织增殖指数（93.15％）。具有1 mg L-1 BA + 0-0.4 mg L-1 NAA（65.57-81。01％）在45μmolm-2 s-1的光强度下。当不定芽在0.4 mg L-1 NAA + 0.4 mg L-1 IBA的MS培养基上接种时，可获得最高的根长（15.57 mm）和最高的生根频率（每个芽17根）。移植苗的成活率约为100％。有效的微繁殖方案在11周内使花色重生花序再生植物。结论本研究确定了光强度和植物生长调节剂（PGR）的最佳组合，以改善组织培养繁殖过程中Haworthia的器官发生。这种优化的方案表明光强度是有效愈伤组织或枝条再生的重要因素。这些结果表明，优化光照条件对于将来的商业化种植非常有用，