Spore Propagation And Protein Nutrient Value Of Several Common Edible Ferns In China

Wild vegetables collection is a tradition and the application of edible ferns can be traced back to more than 3,000 years ago in China.There are abundant wild fern resources in our country,but the development of edible fern resources still have many problems,such as limited development species,harvest time concentration,unclear nutrient value especially protein nutritive value and so on,have greatly influenced on consumer's purchase demand.In this study,Chinese common edible fern species,ethnobotanical catalog and quantitative research were investigated and listed.Several kinds of potential ferns eat by wide range ofpeople from different area were cultured from spore,and the suitable system of fern propagation technology was established as well.In addition,crude nutrient and animo acids of edible parts from cultivars were also described here.The aim of this research is to provide a theoretical and useful practical basis for the developent of edible fern resources,then maximize its utilazation.Firstly,we investigated 204 people from 24 provinces,municipalities and autonomous regions of China using ethnobotany methods for Chinese common edible ferns,with 39 species.Amang them,Botrychium ternatum,Anisocampium niponicum,Cornopteris crenulatoserrulata,Diplazium dilatatum Blume,Microsorum fortunei,Microsorum insigne and Histiopteris incisa was reported for the first time.Our survey data was less than 104 species compared with literature reports,as a result of many edible ferns reported in literatures were generally used for other aspects in the actual production and life.An ethnobotanical catalog of common edible ferns in China with species,vernacular name,edible parts,edible methods and distribution area was created.Besides,Jaccard index and utilization frequency were also analysed.Results showed that the Jaccard index of edible ferns in Jiangxi and Fujian was highest with 0.50 while Hainan and Henan,Hebei,Sichuan,Guangxi,Inner Mongolia and Shanxi were no common in edbile ferns' uses,whose Jaccard index were all 0.The most commonly edible fern,Pteridium aquilinum var.latiusculum,whose utilization frequency is0.418,in turn,is Callipteris esculenta,Ceratopteris thalictroides,Osmunda japonica,Blechnum orientale,Matteuccia struthiopteris and Neottopteris nidus,all of them have development potential.Secondly,we cultured the spores of 4 typical ferns—C.esculenta,M.struthiopteris,P.latiusculum and C.thalictroides.Meanwhile,spore propagation characteristics and the time ofthe gametophyte development at each stage were observed and recorded.Results showed that the spore germination types of 4 species were all of Vittaria-Type,except for gametophyte development of C.thalictroides was Ceratopteris-Type,the other three types were all Adiantum-Type.Cyclogenl of C.esculenta,M.struthiopteris,P.latiusculum and C.thalictroides respectively are 80 d,64d,42 d and 33 d.By compiling the reported data,the culture conditions,such as light and temperature,were analyzed in 4 key development stages,including spore germination,prothallus,sexual organs and young sporophyte.We found that(1)longer illumination time may promote spore germination in the range of 9 to 24 hour;(2)while higher light intensity may prolong the formation of prothallus in the range of 1000 to7000lx;(3)growth rate and temperature had no correlation during gametophyte formation in the range of 20 to 25 ?.Thirdly,we detected basic nutrient composition and amino acids composition of 4 edible ferns from spore propagation,and the chemical assessment methods including fuzzy identification,chemical score,amino acid score,essential amino acid index,chemical biological value,nutrition index and ratio coefficient of amino acids were applied for overall nutritional assessment of their proteins for the first time.It is worth mentioning that(1)all 4edible ferns have some common characters with high protein and fat content,rich in mineral elements as well as crude fiber content.Besides,their amino acids contents are abundant and essential amino acids ratio is close to 40% of total amino acids,which shows that their protein nutritional value are higher;(2)The highest total amino acids among 4 ferns was 974.2 mg/g protein in P.latiusculum,next with 760.3 mg/g protein in M.struthiopteris and the lowest was670.7 mg/g protein in C.thalictroides;(3)Leucine was the most abundant essential amino acid and no significant difference in 4 samples while glutamic was the most abundant non-essential amino acid in all the samples tested.P.latiusculum's glutamic content was the highest with 319.8 mg/g protein,3.3 times higher than C.esculenta,2.6 times higher than M.struthiopteris,3.0 times higher than C.thalictroides;(4)The first limiting amino acid of 4species were all methionine + cysteine;(5)Compared with Apium graveolens var.dulce,the protein nutritive value of Pteridium aquilinum var.latiusculum was the highest,followed by M.struthiopteris,C.esculenta,A.dulce and C.thalictroides.Therefore,P.latiusculum,M.struthiopteris and C.esculenta as new cultivated vegetables have great potential for development.Although protein nutritive value of C.thalictroides was lower than A.dulce inprotein nutritive value,it still has great development potential because it belongs to second grade national protected endangered plants.