Study On Quality And Chlorophyll Fluorescence Characteristics Of Wild And Cultivated Apocynum Venetum

Apocynum venetum is a perennial plant with many good characters, such as draught tolerance, salt and alkaline tolerance, cold tolerance, heat tolerance and wind resistance, which is of higher value in fiber and medicine. Both the dynamic laws of nutrient and total flavonoid accumulation and characteristics of fast chlorophyll fluorescence induction dynamics of wild and cultivated Apocynum venetum were studied by such methods as wild investigation, measure, field tests, physical and chemical analysis, and chlorophyll fluorescence technology. The aim was to find out the difference of photosynthetic efficiency, explore their suitability and best utilize time of wild and cultivated Apocynum venetum as forage and medicinal plant, and to promote the resource to be developed quickly. The results were as follows:(1) With the prolonging of growth stage,the stem/leaf ratio and crude fiber content of wild and cultivated Apocynum venetum at mature period were increased by 3.36, 1.14 times and 1.17, 1.21 times, respectively, compared to those at seedling stage. However, the crude protein and ash contents at mature period were 22.65%, 39.90% and 48.89%, 80.32% of those at seedling stage, respectively. There was no obvious differences in crude fat content. Overall, the nutritional value of cultivated Apocynum venetum was lower than that of wildness. Both of those presented a continuous descending trend during the whole growing period. According to above study results, the best collecting time of Apocynum venetum was suggested before florescence.(2) The total flavonoid contents, which is the main bioactive substances, in leaf and stem of wild Apocynum venetum, were 20.77 and 3.54 times as many as those of cultivated Apocynum venetum. All the trends of total flavonoid contents in leaf of wild and cultivated Apocynum venetum and stem of wild Apocynum venetum increased first and then decreased. However, it is opposite to that in stem of cultivated Apocynum venetum. Overall, the medicinal value of wild Apocynum venetum was higher than that of cultivation. The leaf and flower were suggested to be the best organs used as natural medicine at anthesis.(3) The wild and cultivated Apocynum venetum had similar OJIP curves, but fluorescence intensity of wild Apocynum venetum was lower. Based on reaction center(RC), there were no significant difference in absorption flux per RC(ABS/RC) and dissipated energy flux per RC(DIo/RC), but the wild Apocynum venetum had higher trapped energy flux per RC(TRo/RC) and electron transport flux per RC(ETo/RC). Compared to cultivated Apocynum venetum, the absorption flux per CS(ABS/CSo), trapped energy flux per CS(TRo/CSo), electron transport flux per CS(ETo/CSo) and dissipated energy flux per CS(DIo/CSo) of wild Apocynum venetum significantly reduced, because of the decrease of density of RC(RC/CSo), 67.23%, 69.26%, 70.38% and 60.69% of those in cultivated Apocynum venetum, respectively. However, maximum quantum yield for primary photochemistry(φPo) and performance index on absorption basis(PIabs) of wild Apocynum venetum were 1.03 and 1.22 times as high as those of cultivated Apocynum venetum. Overall, wild Apocynum venetum had better resistibility.