Studies On Photosynthetic Characteristics, Cytology And Content Of Total Alkaloids Of The Genus Lycoris From Anhui Province

The species in Lycoris Herb. of Amaryllidaceae which are all typical bulbous geophytes with leaf appearing in autumn or spring, are endemic to East Asia and principally native to China, Japan and Korea. To date, studies of the genus Lycoris have focused mainly on morphology and anatomy, karyotypes, tissue culture and propagation, medicine and molecular aspects. Little is known about the leaf photosynthetic characteristics of Lycoris species. All species in Lycoris are traditional medicine, while the medicine elements of only a few species have been separated and identified. There are many prodigious disputes remained on the systematic and karyotypic studies of the genus Lycoris.This paper made detailed studies through measuring photosynthetic characteristics, analyzing karyotype and determining the content of total alkaloids on the materials including seven species of the genus Lycoris and different populations of L. radiata and L. chinensis from Anhui province. It could afford some basic scientific data for the discussion on the systematic ralationships and karyotype evolution of the genus Lycoris, and the further exploitation and comprehensive utilization of the Lycoris resources. Moreover, much difference was found not only in different Lycoris species, but also in different inter-populations and intra-populations of L. radiata and L. chinensis. The results were as follows:1. The diurnal changes of gas exchange and chlorophyll fluorescence parameters of four species with leaf appearing in autumn and three species with leaf appearing in spring in the genus Lycoris from Anhui province were determined and compared by a portable photosynthesis analysis system (CI-340). The results showed that marked difference existed in photosynthetic characteristics among different species; the other six species all exhibited a typical decline which was not observed in L. aurea in net photosynthesis rate (PN) during midday; all species had relatively low light saturation point (LSP), low light compensation point (LCP) and high apparent quantum yield (AQY), with the ranges being 322~1189μmol m-2 s-1, 8.11~15.36μmol m-2 s-1 and 0.0457~0.0798, respectively. It was supposed that the seven species were all typical shade plants.2. The effects of shading on the growth, leaf photosynthetic characteristics and chlorophyll fluorescence parameters of Lycoris radiata var. radiata (3n=33) were determined under differing irradiances. The plants experienced a pronounced depression in PN under full light at midday unlike those under shading condition. It was indicated that 15 % of ambient irradiance was too low and the open sky irradiance was too high for L. radiata var. radiata growth. When the integrated daytime carbon gain, leaf area and total leaf area per plant which are the main factors determining the productivity of L. radiata var. radiata plant were taken into account together, this species could be grown in moderate-shade environment with about 60~70 % of ambient irradiance to promote its growth.3. Great variations existed in the karyotype of the genus Lycoris, and a lot of new karyotypes and chromosome numbers were found by detailed cytological analysis. Tremendous inter-populational and intra-populational variations were also found in the karyotype of L. chinensis: (1) the variation of the chromosome numbers was very great, from 16, 17, 18, 19, 21 to 24; and one population of triploid (3n=24) cytotype (Huangpushan Population CytotypeⅠ) was first discovered here; (2) the terminal point chromosome (T) had diverse variations and some rearranged chromosomes which were aberrant had been found; the aberrants included small median centromeric chromosome (m'), submedian centromeric chromosome (sm), subterminal centromeric chromosome (st), terminal centromeric chromosome (t) and satellite chromosome (SAT); (3) Most of the karyotypes of L. chinensis were"3B"type, but there were also some"2B","2C"or"3C"types. The results of studying on the karyotypes of L. straminea and L. houdyshelii being new records in Anhui province showed that L. straminea probably derived from hybridization between L. chinensis and L. radiata var. pumila, and L. houdyshelii was possibly from hybridization between L. radiata var. pumila and L. chinensis or L. longituba.4. The best technological conditions for ultrasonic extraction of total alkaloids in L. chinensis were explored by one single factor and orthogonal experiments and the contents of that in different organs and in bulbs during different growth stages and from different places were determined. It was indicated that with the ultrasonic frequency being 40 KHz, the optimum technological conditions were: temperature at 60°C, the extraction reagent of 65% ethanol, material to extraction reagent 1 : 20, and the extraction time for 2 hours. There were significant differences in the content of total alkaloids among different places. The content of total alkaloids in fruit was the highest, followed by the inflorescence, with the lowest in leaf. The content of total alkaloids in bulb was lower than that in reproductive organs.