Comparative study on photosynthetic characteristics of different ploidy Rhodiola sachalinensis germplasm / 中国中药杂志

<p><b>OBJECTIVE</b>To compare the photosynthetic characteristics difference of different ploidy Rhodiola sachalinensis germplasm and provide the scientific basis for their cultivation.</p><p><b>METHOD</b>LI-6400/XT photosynthesis system was used to measure leaf light response curve and CO2 response curve of diploid and autotetraploid. Biomass, leaf area, stomatal characteristics and chlorophyll content differences were compared in the study.</p><p><b>RESULT</b>Stomata of the two germplasms were open during daytime obviously, and stomata conductance responded to the changes of light intensity and CO2 concentration which was not consistent with the characteristics of CAM (crassulacean acid metabolism) plants. Light compensation point of autotetraploid was significantly lower than that of the diploid, and light saturation points of both germplam were close, and their light saturation points were near 500 micromol x m(-2) x s(-1). Quantum efficiency of autotetraploid was significantly higher than the diploid, and the net photosynthetic rate of autotetraploid significantly higher than the diploid when light intensity was higher than 500 micromol x m(-2) x s(-1). Stomata conductance, transpiration rate of autotetraploid was also significantly higher than that of diploid. Biomass, leaf area, stomata diameter and chlorophyll content of autotetraploid were much higher than that of diploid, while the stomata density of autotetraploid was less than diploid.</p><p><b>CONCLUSION</b>The results above provide scientific basis for the cultivation of different ploidy Rh. sachalinensi germplasm.</p>

Acquiring homozygous tetraploid germplasm by PEG-mediated protoplast fusion of Rhodiola sachalinensis / 中国中药杂志

<p><b>OBJECTIVE</b>To acquire homozygous tetraploid germplasm of Rhodiola sachalinensis.</p><p><b>METHOD</b>PEG-mediated protoplast fusions were conducted using callus of Rh. sachalinensis as materials. Protoplast fusion products were embedded and cultured in low-density, low-melting-point agar and marked according to the protoplast size, and single-celled sister lines were established to acquire genetically homozygous tetraploid germplasm.</p><p><b>RESULT</b>R(D) and R(M) of newborn daughter cells or protoplasm, metaphase cells or protoplasm were approximately in line with the formula R(D) = 0.793 7R(M). The change range in diameter of the diploid cells without fusion, two protoplasts fusion product were: 16.7 microm < or = R < 21.3 microm, 21.0 microm < or = R' < 26.8 microm respectively. There is an overlap between the two diameter ranges. The protoplast inoculation density of 1 x 10(4) cells x mL(-1) was appropriate when protoplasts were anchored by low-intensity, low-melting-point agar. Under the conditions of this density, plating efficiency was high and single cell origin of the sister lines microclones grew rapidly, and it was easy to mark the single cell microclones, and separate from each other to subculture. The chromosome counts results showed that chromosome numbers of diploid and tetraploid of single cell lines were 26 and 52, respectively. The result from flow cytometry assay showed that there is no presence of chimerism in single-cell regeneration plantlets.</p><p><b>CONCLUSION</b>The results of this study provide a scientific basis for polyploid breeding of Rh. sachalinensis.</p>

Protoplast isolation and plant regeneration from leaves of Rhodiola sachalinensis / 中草药

Objective To isolate protoplasts from tube plant leaves of Rhodiola sachalinensis and regenerate plantlets after protoplast culture.Methods Preculture treatment and size of explants,enzyme concentration,mannitol concentration in enzyme mixture related with protoplasts isolation were studied to determine the superior optimized conditions.Results Explants could be used to isolate protoplast without dark preculture,and leaf length should be longer than 1.5 cm.The best incubating enzyme solution contains 1.0% cellulase Onzuka R-10,0.5% Macerozyme R-10,10 mmol/L CaCl2?2H2O,0.1% MES,0.7 mmol/L KH2PO4,and 0.5 mol/L mannitol.The enzyme and explants mixture were shaken for 4 h at 25 ℃.The protoplasts yield and viability were 39.43?106/g fresh weight and 78.6%,respectively.Purified protoplasts were cultured in medium 1/2 MS+1 mg/L 2,4-D+0.5 mg/L ZT+0.5 mol/L mannitol +500 mg/L hydrolysis of casein initially with shallow liquid layers,and calli formed within 40 d.After calli were transfered to MS+1 mg/L 6-BA+0.1 mg/L NAA,adventitious buds were induced from calli.Shoots longer than 2 cm rooted within 30 d when they were transfered to 1/2 MS medium.Conclusion The study provides the scientific base for protoplast fusion in polyploidy breeding of R.sachalinensis.