Concentrations of cytokinin and the use of agricultural residues in the in vitro propagation media of highbush blueberry

ABSTRACT: The objective of the research was to evaluate cytokinin concentrations and agricultural residues as physical structuring agents of the culture medium in the in vitro propagation of highbush blueberry (Vaccinium corymbosum ‘Duke’). To that end, three different concentrations of 2-isopentenyladenine (2iP) (0, 5, and 10 mg L-1)in woody plant medium (WPM) and five structuring agents (in natura rice husks, carbonized rice husks, coconut fiber, S-10 Beifort®, and agar)were tested. After 60days of culture, the following parameters were evaluated: survival (%),sprout and shoot lengths (cm),propagation rate, number of sprouts, and shoot dry mass (g). The substrates used as structuring agents were analyzed in terms of pH and electrical conductivity. The in natura rice husk, S-10 Beifort®, and carbonized rice husk did not differ from the agar in terms of the sprout length. The shoots were longer (1.64 cm) in cultures within natura rice husk than in other treatments. In the absence of 2iP, S-10 Beifort® resulted in the highest propagation rate (2.97). Concerning the number of sprouts, S-10 Beifort®, in natura rice husks, and carbonized rice husks did not differ from agar. However, when the regulator was added, the agar performed better in comparison to the other residues. Thus, in natura rice husks, carbonized rice husks, and S-10 Beifort®are potential physical structuring agents of the culture medium that can be used without 2iP.

摘要：本研究旨在评估细胞分裂素（cytokinin）浓度与农业废弃物作为培养基物理结构化剂，在高丛蓝莓（highbush blueberry，Vaccinium corymbosum ‘Duke’）离体快繁中的应用效果。为此，实验在木本植物培养基（woody plant medium，WPM）中设置3种浓度的2-异戊烯基腺嘌呤（2-isopentenyladenine，2iP）处理（0、5及10 mg·L⁻¹），并测试了5种物理结构剂：天然稻壳、炭化稻壳、椰纤维、S-10 Beifort® 与琼脂。培养60天后，测定如下指标：存活率（%）、芽与嫩茎长度（cm）、繁殖系数、芽数及嫩茎干质量（g）；同时对作为结构剂的基质开展pH值与电导率分析。
结果表明：天然稻壳、S-10 Beifort® 及炭化稻壳的嫩茎长度与琼脂无显著差异；其中天然稻壳基质中的嫩茎最长，达1.64 cm，优于其余处理组。在未添加2iP的情况下，S-10 Beifort® 获得最高繁殖系数（2.97）。在芽数指标上，S-10 Beifort®、天然稻壳与炭化稻壳的表现与琼脂无显著差异，但当添加该生长调节剂后，琼脂的表现优于其余农业废弃物基质。
综上，天然稻壳、炭化稻壳与S-10 Beifort® 可作为潜在的培养基物理结构化剂，且无需添加2iP即可投入应用。