On the application of flow cytometry in the genomic size determination of bamboo plants

Abstract

Objective This research is aimed to study the effects of material tissue and the treatment method on the genome size of bamboo plants with the ultimate purpose to improve the genome size determination accuracy of bamboo plants. Method With the leaves and shoots of different bamboo species selected as materials, and the rice used as the reference standard while the nuclear staining time set for 9 different gradients, that is 1, 3, 5, 7, 9, 12, 18, 24 and 30 minutes, an investigation was carried out of the tissue sites and staining materials of different bamboo plants with the employment of flow cytometry. Result (1) With the same bamboo species, the leaves and shoots were similar in the fluorescence peak and genome size with the genome size difference range as narrow as 0.04~0.20 pg. (2) The 12 bamboo species are different in their nuclear staining time, with the fluorescence intensity of Sinobambusa tootsik, Sinobambusa tootisik f. albo-striata, Pseudosasa japonica var. tsutsumiana, Pseudosasa japonica f. akebono, Indocalamus decorus, Sasaella glabra f. albo-striata and Chimonobambusa mamorea f. variegata reaching the maximum within 1 minute, that of Bambusa multiplex and Phyllostachys sulphurea reaching the maximum within 3 minutes, that of Pseudosasa amabilis var. amabilis and Thyrsostachy ssiamensis reaching the maximum within 5 minutes, while that of Phyllostachys sulphurea (leaf) reaching the maximum within 7 minutes. (3) The fluorescence intensity of the 12 bamboos varies greatly from 1 to 30 minutes, all exceeding 5% except for the leaf of P. amabilis var. amabilis, T. ssiamensis, B. multiplex and the shoot of S. tootsik. In fact, the fluorescence intensity of P. japonica var. tsutsumiana and S. glabra f. albo-striata have reached 12.93% and 12.88% respectively. (4) As for the genome size of 12 bamboo species, 2 tropical woody bamboo species of B. multiplex and T. ssiamensis changed from (2.64±0.54) pg to (2.69±1.01) pg, however, that of the 10 temperate woody bamboo species changed from (3.76±1.51) pg to (5.73±1.85) pg; of the 10 temperate bamboo species, the genome size of Phyllostachys changed from (3.76±1.51) pg to (3.91±0.95) pg, yet that of the other bamboo genus changed from (4.82±0.54) pg to (5.73±1.85) pg, which is obviously larger than Phyllostachys. Conclusion (1) Both leaves and shoots of bamboo can be used as experimental materials to determine their genome sizes by flow cytometry. The nuclear staining time has a certain effect on the determination of the bamboo genome size with 3 to 5 minutes as the optimal staining time. (2)The genome size of tropical woody bamboo species is obviously smaller than that of temperate woody bamboo species while among the temperate woody bamboo species, the genome size of Phyllostachys is obviously smaller than that of the other genus bamboo species. [Ch, 1 fig. 5 tab. 29 ref.]