Effects of 1-butanol, neomycin, and calcium on the photosynthetic characteristics of pepc transgenic rice

Abstract

The effects of 1-butanol, neomycin, and calcium on the photosynthesis of pepc transgenic rice were studied with over-expressed pepc transgenic rice (PC) of the 8th generation as study materials and with non-transgenic wild type (WT) rice and maize, a typical C4 plant, as control. The results indicated that 0.04% 1-butanol, 0.1 mmol L−1 neomycin, and 0.05 mmol L−1 calcium ions had not a significant effect on the net photosynthetic rate (Pn) of the three tested materials. The stepwise multiple linear regression analysis showed that the pepc transgenic rice maintained its relative high net photosynthesis rate through increasing stomatal conductance. It was proved by the scanning electron microscope (SEM) that compared with the WT, the stomatal density of PC leaves increased while the stomatal aperture also increased under the 1-butanol treatment. The separate 1-butanol treatment significantly inhibited the PEPC activity of PC and maize leaves, while neomycin treatment alone had no significant effects on the PC and maize. However, the combined treatment with 1-butanol and neomycin evidently promoted the PEPC activity of PC and WT. Moreover, exogenous calcium significantly promoted the PEPC activity of the three materials. It is clear that the exogenous regulation on PEPC enzyme of pepc transgenic rice is different from both C4 and C3 plants.