| Coix plants of the Graminea,Coix lacryma-jobi L.,are important food-medicine homologous plants,which is widely distributed in Southeast Asia.The seeds are of high value in nutrition,health-protection and in medicinal purposes.However,due to its past inadequate emphasis on research,the cultivation area has been on a sharp drop and its wild resources has been greatly reduced.In recent years,with the increase of the awareness of health protection among the public,the researches of Coix lacryma-jobi L.,especially on its cultivation,germplasm resources conservation and the roles in food and medicine,has been on the rise.In thi`s research,the shapes,dimensions and one-hundred-grain weight of the fruits and caryopses and the hardness of fruits of the 11 current cultivars and 2 wild varieties of Coix L.collected from 9 Provinces across China,were measured and compared;the agronomical traits and reproductive growth features in field cultivation in Chongqing were comparatively analyzed;the main quality traits such as the contents of various carbohydrates,proteins,fats and fatty-acid composition etc.of Coix caryopses were also analyzed;preliminary SOD,POD and EST zymogram analyses of the caryopses of different varieties and different color of fruit shells have been performed;and the phylogenetic trees based on the ITS sequences of Coix obtained from PCR amplification and those from the GenBank were constructed and analyzed.Major results are as follows:1.Shapes,Dimensions of Fruits and Caryopses,Hardness of Fruits and Other Agronomic Traits of the Different Coix L.VarietiesBased on field observation,we supposed that the Coix fruit shell coloration may have something to do with genetics,degree of pollination and embryo development as well as environmental factors(such as the presence and intensity of UV light).Therefore the Coix fruits(thereby caryopses)were sorted as black-and white-shelled in this research.It has been shown that the dimensions of Coix fruits(expressed as long×short diameter)were 8.43~11.12 mm×5.60~7.44 mm,with long/short diameter ratios of 1.21~1.82.Those of the caryopses were 4.36~5.42 mm×4.08~5.54 mm,with long/short diameter ratios of 0.89~1.23.There was no significant difference in fruit and caryopsis dimensions between different shell colors among the same variety.The shapeof the caryopses was more spherical than that of the fruits and the shape of the wild Coix fruits was more spherical than that of the cultivated.Comparison on hardness of the fruits showed that the fruits of the wild Coix were harder than those of the cultivated,which needs tools to crack the shells.Measurements and analyses of the agronomical traits of the Chongqing cultivated Coix varieties showed that the plant heights was ranged from 81.4 to 146.0 cm,the wild Coix plant height was higher than the cultivated varieties,with the highest being HCYSYY and BBYSYY and the shortest being HBYY,and 5 varieties(HBYY,LYYH,GXYY,FJYY and LNBK)could be categorized as exceptional-dwarf type and the other8 varieties,as dwarf-typed;the number of tillers was from 3.4 to 10.7 per plant,with the largest and lowest being BBYSYY and LNBK respectively;the diameters of the main stalk ranged from 0.78 to 1.24 cm,with the thickest being ZYYH,XRXHK and XRXBK and the thinnest being FJYY and HBYY;the number of nodes of the main stalk was from 6.0 to 12.6,XRXHK and XRXHK being the highest and the lowest being LNBK,PNYH and FJYY;the length of the last 5th leaf was from 33.75 to 53.75 cm,with the longest being ZYYH and HCYSYY;the width of the last 5th leaf was from2.93 to 4.08 cm with the widest being XRXBK and the narrowest being PNYH;the leaf color was dark green and yellowish green.One-hundred-grain weight of Coix fruit ranged from 5.85 to 19.84 g,with the highest being the black-shelled HCYSYY;the one-hundred-grain weight of black shelled Coix fruit was greater than that of the white shelled of the same variety.One-hundred-grain weight of Coix caryopses was from 2.80 to 7.85 g,with the highest being XRXBK;and the one-hundred-grain weight of black shelled caryopses was greater than that of the white shelled of the same variety.The kernel percentage of Coix L.was from 29.84 to 64.14%,the highest being XRXBK;and the kernel percentage of the white shelled was bigger than the black shelled of the same variety;kernel percentage of the wild Coix was the lowest.The kernel percentage may be related to the hardness of the shell.Observation of the reproductive growth in field showed that the time duration from heading to stamen withering was from 7 to 20 days.The heading and stigma growth of most varieties were in mid-June and the flowering and withering of the male flowers were mostly in First-July.The reproductive growth of the wild Coix was later and shorter in duration than the cultivated ones.In all the varieties the development of male flowers were prevalently later than that of the female flowers of the same spikelet.However,also observed was some proportions of earlier development of male flowers as well as synchronization of both.There were white and purple stigmata observed among all the Coix varieties and in some varieties there were plants with white stigmata and plants with purple stigmata coexisted within the same variety.and both stigma colors coexisted in separate plants and in various proportions among the other varieties.Usually bifurcated stigmata were observed in majority among all the varieties.However there were also some proportions of tri-and hexa-furcated stigmata of both colors.There were also green and purple stalks observed and they were interestingly corresponding to the white and purple stigmata.It is suggested that there might be some genetic linkage between the two traits and further researches are needed to ascertain this relationship.2.Analyses of the Main Quality Traits of the Caryopses of Different Coix L.VarietiesThe water content of caryopses was from 10.51 to 13.32%;the water content of the wild Coix was lower than that of the cultivated ones;the reducing sugar content ranged2.91 to 11.99%;soluble sugar content was 7.21 to 17.46%;and the total sugar content was 27.64 to 40.24%.The amylose content was 4.13 to 6.16% and amylopectin content was 46.69 to 61.06%;the crude protein content was 13.68~21.18%;prolamin content was 0.58 to 2.41%;soluble protein content was 1.5 to 3.69%;the crude protein contents of the two wild Coix were the highest,up to about 20.0% and contents of the other components showed not much difference to the cultivated varieties;the average contents of reducing sugar,soluble sugar,amylose,prolamin and soluble protein in white shelled caryopses were higher than those of the corresponding black shelled ones.Except the amylose content,the contents of other components were significantly different among differently colored shells.The crude fat content was 5.19 to 11.65%,with an average of 8.02% and the lowest and highest were respectively of XRXBK and ZYYH;the relative content of unsaturated fatty acids were very high,up to from82.69% to 89.83%.The total antioxidant capacity was 11.92 to 70.57 mM/g;for the black shelled,the lowest was XRXHK and the highest was HBYY and for the white shelled,the lowest was XRXBK and the highest was ZYYH;the total antioxidant capacity of the white shelled was higher than the corresponding black shelled.3.Preli minary Analyses of SOD,POD and EST Zy mogra ms of the Caryopses inDifferent Coix L.Varietie sThe preliminary analyses of SOD,POD and EST zymograms of the caryopses of different Coix L.varieties showed that there were roughly three bands for both SOD and EST and many indistinct bands of POD.The zymograms of the 3 enzymes in caryopses were unable to distinguish the different Coix varieties.4.Genetic Diversity Analyses Based on Internal Transcribed Spacer(ITS)of Different Coix L.VarietiesAnalysis of the ITS sequences amplified from different Coix L.varieties showed that the length of ITS sequence of Coix L.is 588 to 589 bp and there has been 17 variable sites,among which 12 transversions,2 transitions,2 deletions and 1 insertion,with a variation rate of 2.9%.The ITS sequence of individual plants in FJYY has repeated segments.The N-J tree constructed from ITS of individual plants showed that the different Coix from different regions has no close relationship geographically;the N-J tree constructed within the Coix genus showed that the genetic relationship among Coix lacryma-jobi var.ma-yuen,Coix lacryma-jobi L.and Coix agrestis Lour's is closer but all the three are genetically distant from Coix gasteenii;the N-J tree constructed with the ITS sequence of Coix L.and its related genera and species suggest that Coix L.is closest to Dioscorea oppositifolia,closer to Erianthus,Miscanthus,Narenga and Sorghum but is distant from Discorea ploystachy and Dioscorea alata.These results provided some novel ideas for the further studies of Coix L on its breeding,genetics,basic biology etc. |
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