温度对马尾松组培单芽不定根发生的影响

Effects of temperature on adventitious root formation of tissue-cultured shoots in Pinus massoniana

关键词:  组培快繁, 生根率, 生根解剖, 不定根诱导

Key words:  rapid propagation by tissue culture, rooting percentage, rooting anatomy, induction of adventitious root

摘要:

马尾松(Pinus massoniana)组织培养生根困难,该研究在严格控制光温条件的光照培养中,以马尾松无性系组培继代芽为材料,分析了在不同温度处理下马尾松组培单芽生根率、生根时间、根系条数和移栽成活率等生根能力指标以及生根解剖构造的变化。所有数据均采用SPSS 19.0统计分析软件,进行单因素分析(ANOVA)的显著性检验及最小显著性差异法(LSD)的多重比较。结果表明:在25 ℃最适温度培养下,马尾松组培生根效果较佳,移栽成活率最高,可达98.1%。低温处理下,生根时间显著延长,根系条数减少,生根率偏低; 高温处理下,根茎愈伤组织明显,移栽成活率显著降低。从生根解剖构造来看,马尾松不定根主要由维管形成层细胞分化而成。与25 ℃适温处理相比较,在20 ℃较低温处理下,细胞分裂活动缓慢,不定根原始体诱发较少; 而在30 ℃较高温处理下,细胞活动旺盛,但髓射线与维管组织细胞染色颜色加深、排列紧密,将诱发的不定根原基细胞团区隔成带状或片状。该研究结果探讨了培养环境温度对马尾松组培单芽生根能力的影响,为马尾松组培苗生产提供了参考。

Abstract:

Pinus massoniana is one of the most important tree species for afforestation in South China, and it is of great economic value and ecological benefit. P. massoniana is famous for the wide application of its timber and resin, being of very important high-value tree species. Breeding programs for P. massoniana were initiated in the 1980s in China. To capture the best genetic stock from the breeding program, an efficient system for rapid clonal propagation is of considerable value. Therefore, the application of biotechnology and especially tissue culture provides an important tool to propagate the selected genotypes. The regeneration of plants under aseptic and controlled environmental conditions is referred to as micropropagation because very small pieces of plant tissue or organs are used as starting vegetative tissue. Previous studies revealed that P. massoniana was hard to root by tissue culture, and culture temperature was correlated to the stability of in vitro rooting in P. massoniana. In the illumination incubator with strictly controlled conditions of light and temperature, variations of rooting ability index, including rooting percentage, rooting time, number of roots and transplantation survival percent, and rooting anatomic structure from in vitro single buds were investigated using subcultured shoots of Pinus massoniana clone under rooting treatments of different temperatures. SPSS 19.0 statistic software was used to analyze those data. In vitro rooting performance was good and the highest transplantation survival percentage was 98.1% for shoots of P. massoniana cultured at 25 ℃. Rooting time was prolonged, number of roots was decreased and rooting percent was low under the lower temperature treatment, while rhizome callus was serious and transplantation survival percent remarkably was reduced under the higher temperature treatment. For P. massoniana, vascular cambium cells were differentiated into adventitious root in terms of root anatomical structure. Compared with the normal temperature treatment at 25 ℃, cell division was passive, induced adventitious root primordial at 20 ℃ treatment, however, cells were active, the color of stained cells from pith ray and vascular tissue was deepened and those cells were arranged densely, resulting in induced adventitious root primordial was separated into being zonal or schistose at 30 ℃ treatment. This study revealed the effects of temperature on in vitro rooting ability, and provides the supports for the industrial production of tissue cultured plantlets in P. massoniana.