The Study Of The Relationship Between Nuclear DNA Content Of Hippophae L. Species And Their Hybrid Origin

In this study,we aimed to examine nuclear DNA content of Hippopha goniocarpa and H. gyantsensis with possible hybrid origin and their parental species(H.rhamnoides subsp. sinensis,H.neurocarpa subsp,neurocarpa,H.rhamnoides subsp,yunnanensis and H. neurocarpa subsp,stellatopilosa),respectively,applying the recently well-established method flow cytometry(FCM) to confirm the hybrid origin of H.goniocarpa and H.gyantsensis. We also compare the same species from different regions,in order to elucidate the influence of environment(altitude and latitude) on nuclear DNA content.(1) The nuclear 2C DNA value of H.goniocarpa was 2.95±0.08pg,while those of H. rhamnoides subsp,sinensis varied from 2.54±0.09pg to 2.66±0.12pg pg and those of H. neurocarpa subsp,neurocarpa altered from 3.15±0.19pg to 3.49±0.06pg.The nuclear DNA content of H.goniocarpa was intermediate between those of two parental species,and significant variation was detected between the hybrid species and their parental species used One-way ANOVA(P＜0.01),confirming that this species is of diploid hybrid origin and further suggesting it is at the early speciation stage.(2) The mean nuclear 2C DNA value of H.gyantsensis was 3.55±0.10pg,while those of the parental species H.rhamnoides subsp,yunnanensis(from Zhongdian,Yunnan and Lulang,Xizang) were 2.63±0.13pg and 2.65±0.12pg,respectively,and those of H. neurocarpa subsp,stellatopilosa(from Bangda and Zuogong,Xizang,and Dege,Sichuan) were 3.30±0.06pg,3.22±0.13pg and 3.29±0.07pg.The nuclear DNA content of H. gyantsensis was higher than those of two parental species,and the variation was significant (P＜0.01),showing that this species may be a mature and stable hybrid species.(3) The six Hippophae species contained in our research are as follows:H. goniocarpa,H.rhamnoides subsp,sinensis,H.neurocarpa subsp,neurocarpa,H.gyantsensis, H.rhamnoides subsp,yunnanensis,H.neurocarpa subsp,stellatopilosa,there are nearly no intraspecific difference in most of them(P＞0.05),only H.neurocarpa subsp,neurocarpa and H.gyantsensis showing significant intraspecific differences from different regions(Yushu, Qinghai and Jiangzi,Xizang,respectively),which suggesting that the relationship between environmental factors(altitude and latitude) and the variation of nuclear DNA content in H. rhamnoides genus are uncorrelated,but the exception exists.