[Objective] The aim of this study was to investigate the content changes and their correlations of the photosynthetic pigment,phenols,including total phenols,total flavonoids and anthocyanins,and total saponins of the one-year-old P.notoginseng plants under supplemental UV-B stress in fields.[Method] The one-year-old plants were irradiated by UV-B in field for 1 min per day,and the plants under the UV-B lamp were regarded as a circle center,achieving an annular leaf-sampling.The photosynthetic pigment,phenols and total saponins of the leaves were determined spectrophotometrically.[Result] With the increase of sampling radius,the supplemental UV-B intensity decreased significantly,the contents of chlorophyll （Chl） a,Chl b,Chl （a＋b）,carotenoid （Car） and total photosynthetic pigment （Chl＋Car） of the leaves increased extremely significantly,the Chl a/b and total phenol content （TPC） decreased extremely significantly,but the Chl （a＋b）/Car changes were not significant.The contents of total flavonoids,anthocyanins and saponins all increased due to the increasing of UV-B,displaying dose effects.The UV-B intensity was positively correlated with the Chl a/b,and negatively with the Chl a,Chl b,Chl （a＋ b）,Car and （Chl＋Car） contents; and the two of TPC,total flavonoid content （TFC）,total anthocyanin content （TAC） and total saponin content （TSC） were positively correlated,all reaching extremely significant level.The UV-B intensity was positively and significantly correlated with the total flavonoid content （TFC）,negatively and significantly with the Chl （a＋b）/Car,and positively and insignificantly with the TPC,TAC and TSC.[Conclusion] For one-year-old plants of P.notoginseng,UV-B can decrease the contents of the Chl a,Chl b,Chl （a＋b）,Car and （Chl＋Car） and increase the Chl a/b and TPC,and,furthermore,induce the increases of the TFC,TAC and TSC in a dose-dependent manner.However,UV-B can hardly change the Chl （a＋b）/Car.The supplemental UV-B of well
This paper summarized the possible physiological mechanism by which anthocyanins strengthen the tolerance of plants to drought. Drought stress can in-duce plant cel s to synthesize and accumulate anthocyanins. The photochemical properties, subcel ular accumulation sites and spatial distributions in plant organs and tissues of anthocyanins determine their function of strengthening plant tolerance, which is realized by three possible physiological mechanisms： （1） anthocyanins and their chelated metal ions can optimize the osmoregulation ability of the plant cel s by directly acting as the osmoregulation substances of the cel s, （2） anthocyanins with suitable spatial locations can reduce the photoinhibition of the plants under drought stresses, （3） anthocyanins can effectively maintain and improve the active oxygen-scavenging capacity of the plant cel s under drought conditions. Therein, that the anthocyanins enhance the antioxidant capacity of the plant cel s under drought stresses is probably the main reason for the anthocyanins to strengthen the drought tolerance of plants. This review could provide a reference for the mechanism re-search of the drought resistance and the breeding of the drought-resistant cultivars for the plants holding the ability to synthesize and accumulate anthocyanins.
[Objective] This study aimed to identify red pigment of Panax notoginseng fruits and explore the correlation between pigment content and total saponins of the fruits. [Method] The red pigment of Panax notoginseng fruits was preliminarily identi- fied with specific color reactions and UV-vis spectra, and the contents of the pigment and total saponins were determined via spectrophotometry. [Result] The red hues of the fruits were contributed by anthocyanins and/or the anthocyanidins. The contents of anthocyanins and total saponins of the fruits both decreased along with thinning of the red hues. The content difference of the anthocyanins in fruits with different red hues reached extremely significant level, but that of total saponins just reached significant level. [Conclusion] The red pigment of P. notoginseng fruits is anthocyanins which are of extremely significant positive correlation with total saponins in contents.
Objective] The aim of this study was to simultaneously isolate and identify the main pathogenic fungi of the root rot, black spot and round spot from the Panax notoginseng plants cultivated in Wenshan Eparchy of Yunnan Province of China. [Method] The pathogenic fungi were isolated and purified by using potato dextrose agar （PDA） medium. The morphological identification was accomplished first according to the colony forms of the fungi when cultivated in vitro, then accord-ing to the symptom characteristics and colony forms of the re-isolated fungi in the reverse inoculation experiments. The molecular identification was performed accord-ing to the amplification and alignment of the internal transcribed space （ITS） se-quences of the fungi. The increases of the diameters and thickness of the colonies of the fungi cultivated in vitro were employed to indicate the growth rates of the fungi. [Results] The consistency of the colony forms and symptom characteristics and the 96%-99% similarities revealed in the ITS sequence alignments al proved that the main pathogenic fungi of the root rot, black spot and round spot of the P. notoginseng plants raised in Wenshan were Cylindrocarpon didymium, Alternaria panax and Mycocentrospora acerina, respectively. When cultivated in vitro in the same temperature, humidity and il umination, the increases of the colony diameters and thickness of C. didymium were the highest, fol owed by those of A. panax, then those of M. acerina. During different cultivation periods, the differences of the colony diameters and thickness of the three fungi al reached extremely significant level. However, at the same cultivation time, the differences of the diameters and thickness among the three fungi only reached significant level. [Conclusion] The main pathogenic fungi which result in the root rot, black spot and round spot of the P. notoginseng in Wenshan are C. didymium, A. panax and M. acerina, respec-tively. When these three diseases break out at the same time, the root rot wil spread faste
