Production of deoxyschizandrin and γ-schizandrin in shoot-differentiating and undifferentiating callus cultures of Schisandra chinensis (Turcz.) Baill. (Chinese magnolia vine).

Shoot-differentiating and undifferentiating callus cultures of Schisandra chinensis were cultured, respectively, on six and two variants of the Murashige and Skoog (MS) medium, differing in the concentration of cytokinin, 6-benzyladenine (BA) and auxin, α-naphthaleneacetic acid (NAA). In methanolic extracts from the biomass of both types of culture the amounts of two lignans: deoxyschizandrin and γ-schizandrin were estimated using the HPLC method. The levels of both compounds in the shoot-differentiating callus extracts were dependent on the concentration of BA and NAA in the MS medium variants. The amounts of deoxyschizandrin were high and varied over a wide range from 34.23 to 308.51 mg 100 g(-1) dry weight (DW); the amounts of γ-schizandrin were of a different order and ranged from 1.07 to 22.09 mg 100 g(-1) DW. In the extracts from undifferentiating callus the amounts of both compounds were lower and almost identical on the tested variants of the MS medium, equal, respectively, to about 18.5 mg 100 g(-1) DW deoxyschizandrin, and about 1.0 mg 100 g(-1) DW γ-schizandrin. The maximum amounts of deoxyschizandrin were obtained on the MS medium variant containing 3 mg l(-1) BA and 1 mg l(-1) NAA. These amounts were 7.5 and 5.1 times higher, respectively, than in the extracts from the leaves (41.01 mg 100 g(-1) DW) and fruits (60.72 mg 100 g(-1) DW) of native plant, analyzed for comparison. The maximum amount of γ-schizandrin in shoot-differentiating callus (22.09 mg 100 g(-1) DW) was comparable with its amount in the leaves (22.27 mg 100 g(-1) DW), but 3 times lower than in the fruits (66.50 mg 100 g(-1) DW). The obtained high amounts of deoxyschizandrin in the extracts of shoot-differentiating callus are of interest from the practical perspective.

Intercarpellary growth of pollen tubes in the extragynoecial compitum and its contribution to fruit set in an apocarpous species, Schisandra sphenanthera (Schisandraceae).

PREMISE OF THE STUDY: Apocarpous plants possess carpels that are separated in the gynoecium. Extragynoecial compita, commonly occurring in basal angiosperms, have been proposed to have the potential to increase offspring quantity in apocarpous species through the intercarpellary growth of pollen tubes. To date, the impact of an extragynoecial compitum on fruit or seed set has not been studied in any species. This study investigated the pollen tube pathway between adjacent carpels and its contribution to fruit set in Schisandra sphenanthera. METHODS: We investigated the fruit set ratio in the field and collected hundreds of gynoecia at their full flowering stage. Pollinated carpel ratio and pollen tube pathway observations were performed using fluorescence optics. KEY RESULTS: Pollen grains germinated and tubes extended along the pseudostyle surface. Some of them turned and entered the ovules at the end of the stigmatic crest, whereas others subsequently grew into neighboring carpels through promontory connections located at the base of the unfused carpels. No tubes were found growing on the surface of the receptacle. More than 24 carpels could be fertilized by pollen tubes from one carpel through hand pollination. The pollinated carpel ratio was significantly lower than the fruit set ratio under natural conditions. CONCLUSIONS: Pollen tubes from one carpel can easily cross in the extragynoecial compitum between the adjacent carpels of S. sphenanthera, and this intercarpellary growth of pollen tubes can significantly increase the fruit set of apocarpous species, at least in S. sphenanthera.