[Tissue culture effect of different size explants of Lycoris aurea].

OBJECTIVE: To solve the puzzle about the right size of the explant of wild medicinal plant Lycoris aurea for tissue culture. METHODS: Three-size explants: 9.0 x 8.0 mm, 6.0 x 5.0 mm, 3.0 x 2.0 mm of endothecium bulb-scale joined by a strip of stem plate and middle-layer bulb-scale joined by a strip of stem plate were cultured on two kinds of the medium: MS +9 mg/L BA +5 mg/ L NAA +0.7% agar +3% cane sugar and MS +5 mg/L BA +9 mg/L NAA +0.7% agar +3% cane sugar, and the culture effects of the three-size explants for Lycoris aurea were studied. RESULTS AND CONCLUSION: The results showed that the explant size on 6.0 x 5.0 mm of the endothecium bulb-scale cultured on the medium: MS +9 mg/L BA +5 mg/L NAA +0.7% agar +3% cane sugar had the advantage of forming adventitious buds and roots, and inhibiting brown samples, and to the middle-layer bulb-scale explant of the same size cultured on the same medium was next. Correlation analysis showed that the culture effect of the three-size explants on one kind of medium was significantly correlated with that of theirs on another kind of medium, which further proved that the result of Duncans multiple range test, i.e. if the effect of an explant size on one kind of medium were better, its effect on another kind of medium would also be better. Both Duncan's multiple range test and correlation analysis indicated that the effect of the size on 6.0 x 5.0 mm explant of the double endothecium bulb-scale joined by a strip of stem plate was better than those of the other sizes on the experimental explants, and to that of 6.0 x 5.0 mm size of the double middle-layer bulb-scale joined by a strip of stem plate was next.

Photosynthesis of the flag leaf blade and its sheath in high-yielding hybrid rice 'Liangyoupeijiu'.

Using high-yielding hybrid rice 'Liangyoupeijiu' (LYP9) and hybrid rice 'Shanyou 63' (SY63) as the experimental materials and using (14)C radio-autography, the photosynthetic capacities and distribution of photosynthates in flag leaf blades and sheaths of LYP9 were studied. The results showed that net photosynthetic rates (Pn) of the flag leaf blades and sheaths of LYP9 were much higher than those of SY63; the light transmissivity rates (LT) measured at the medium height of the flag leaf sheaths and the penultimate leaf sheaths were also significantly higher than those of SY63. The incipient activities, total activities and activation percentages of Rubisco in the flag leaf blade and sheath of LYP9 were all higher than those of SY63. The photosynthate transport rate in the sheaths of LYP9, and the quantity of photosynthate transported to the spikes and transformed to economic yield of LYP9 were all higher than those of SY63. The photosynthates produced by the sheaths were mainly transported to spike to make a certain contribution (about 15%) to yield.