廣藿香毛狀根多倍體誘導及其植株再生

為了提高藥用植物廣藿香的次生物質廣藿香醇含量，采用秋水仙素人工誘導染色體加倍技術，進行了廣藿香毛狀根多倍體誘導及其植株再生、倍性鑒定和揮發油組分廣藿香醇含量的測定。結果表明，廣藿香毛狀根多倍體誘導的最佳條件為0.05%秋水仙素處理36 h，其多倍體誘導率可達40%以上；經秋水仙素加倍的廣藿香毛狀根在MS+6-BA 0.2 mg/L+NAA 0.1 mg/L培養基中培養60 d后可獲得毛狀根多倍體再生植株。與對照(二倍體植株)相比,廣藿香毛狀根多倍體再生植株根系更發達、莖更粗、節間變短、葉片的長度、寬度和厚度均較二倍體明顯增大。根尖細胞染色體壓片觀察證實，所獲得的廣藿香毛狀根多倍體再生植株為四倍體，其根尖細胞染色體數約為128；同時，其葉片的氣孔保衛細胞體積及其葉綠體數目均約為對照的兩倍;但其氣孔密度則隨著倍性增加而下降，二倍體植株葉片的氣孔密度約為四倍體植株葉片的1.67倍。GC-MS測定結果表明，廣藿香毛狀根多倍體再生植株的廣藿香揮發油組分廣藿香醇的含量為4.25 mg/g干重，約為二倍體植株的2.30倍。該結果證實毛狀根多倍體化可提高藥用植物廣藿香的廣藿香醇含量。
In order to enhance the content of secondary metabolites patchouli alcohol in Pogostemon cablin, we induced polyploid hairy roots and their plant regeneration, and determined the content of patchouli alcohol through artificial chromosome doubling with colchicine. The highest rate of polyploidy induction was more than 40% when hairy roots were treated with 0.05% colchicine for 36 h. The obtained polyploid hairy roots formed adventitious shoots when cultured in an MS medium with 6-BA 0.2 mg/L and NAA 0.1 mg/L for 60 d. Compared with the control diploid plants, the polyploid hairy root-regenerated plants of P. cablin had more developed root systems, thicker stems, shorter internodes and longer, wider and thicker leaves. Observation of the chromosome number in their root tip cells reveals that the obtained polyploid regenerated plants were tetraploidy, with 128(4n=128) chromosomes. The leaves contained around twice as many stomatal guard cells and chloroplasts as the controls, but the stomatal density declined with increasing ploidy. The stomatal density in diploid plants was around 1.67 times of that in polyploid plants. GC-MS analysis shows that the content of patchouli alcholol in the hairy root-derived polyploid plants was about 4.25 mg/g dry weight, which was 2.3 times of that in diploid plants. The present study demonstrates that polyploidization of hairy roots can stimulate the content of patchouli alcholol in medicinal plant of P. cablin. Copyright © 2014 Chin J Biotech, All rights reserved.