Photosynthetic and fluorescent characteristics of precocious walnut in field
Photosynthetic and fluorescent characteristics of three precocious walnuts Liaoning No.1, Liaoning No.7and Zhonglin No.1 were studied in field.The results indicated that precocious walnuts's photosynthetic "nap" phenomenon was caused by the non-stoma limitation factors.The response curves of photosynthesis in mature precocious walnut leaves to the illumination intensity, air CO2 concentration and leaves temperature could all be described by quadratic equations.The light saturation point values (VLSP) of the three precocious walnut cultivars were in range from 1 106 to 1 750μmol · m-2s-1 , which showed that precocious walnut was a kind of heliophile.Light compensation point values (VLCP) were from 18.12 to 25.04 μmol · m-2s-1, and Liao No.7 showed good adaptability of strong light.The CO2 saturation point values(VCSP) of the precocious walnut cultivars were range from 500to 628 μmol · mol-1 , and CO2 compensation point values(VCCP) were range from 29 to 119 μmol · mol-1, Liao No.7 had maximum carboxylation efficiency and net photosynthetic rates (Pn).The most suitable temperature scope of precocious walnuts photosynthesis was from 28 ℃ to 36 ℃, and Liao No.1 had better adaptability to temperature Correlation of most parameters between fluorescence and photosynthetic were significant.Around noon,primary photochemical efficiency (Fv/Fm), the effective quantum yield of photosystem Ⅱ (EYield) and photochemical quenching coefficient (CqP) were lower than those in other time frame, while non-photochemical quenching (VNPQ)and electron transport rate (RETR) were higher, PS Ⅱ 's activity decreased, photosynthetic effect was low, plants were limited by photoinhibition.But the photoinhibition was a self-protective mechanism, and heat dissipation and light breathing were the main protective ways of the precocious walnuts.
NETL
NSTL
万方数据
维普
