Comparison in photosynthetic characteristics of Larix kaempferi, L. olgensis and their hybrids

Photosynthetic parameters calculated from lightresponse curves and CO2response curves were compared among Larix kaempferi, L. olgensis and their hybrids grown in a cutting orchard to compare their photosynthetic characteristics. The results showed that compared with L. kaempferi, L. kaempferi×L. olgensis had lower Pmax (maximum net photosynthetic rate), AQY (apparent quantum yield), Pm (photosynthetic capacity) and higher Rd (dark respiration rate) and thinner usable range in light quantum and CO2 concentration, while no differences were observed in CE (carboxylation efficiency) and Rp (photorespiratory rate) between the two taxa. L. olgensis×L. kaempferi had lower AQY and Rd but higher Г (compensation point) relative to L. olgensis, while their CE, Rp and LCP (light compensation point) exhibited no differences. Compared with L. olgensis×L. kaempferi, L. kaempferi×L. olgensis had higher Rp and Г but lower CE, while no differences were observed in AQY, Rd, and LCP between the two taxa. In conclusion, our findings show that larch hybrids photosynthetic efficiency does not exhibit super parent heterosis.