Photosynthetic performance of Lycoris radiata var. radiata to shade treatments

Abstract

The effects of shade on the growth, leaf photosynthetic characteristics, and chlorophyll (Chl) fluorescence parameters of Lycoris radiata var. radiata were determined under differing irradiances (15, 65, and 100% of full irradiance) within pots. The HI plants exhibited a typical decline in net photosynthetic rate (P N ) during midday, which was not observed in MI-and LI plants. This indicated a possible photoinhibition in HI plants as the ratio of variable to maximum fluorescence (F v /F m ) value was higher and the minimal fluorescence (F 0 ) was lower in the , and LI plants. Diurnal patterns of stomatal conductance (g s ) and transpiration rate (E) were remarkably similar to those of P N at each shade treatments, and the intercellular CO 2 concentration (C i ) had the opposite change trend. Under both shading conditions, the light saturation point, light compensation point and photon-saturated photosynthetic rate (P max ) became lower than those under full sunlight, and it was the opposite for the apparent quantum yield (AQY). The higher the level of shade, the lower the integrated daytime carbon gain, stomatal and epidermis cell densities, specific leaf mass (SLM), bulb mass ratio (BMR), leaf thickness, and Chl a/b ratio. In contrast, contents of Chls per dry mass (DM), leaf area ratio (LAR), leaf mass ratio (LMR), leaf length, leaf area and total leaf area per plant increased under the same shade levels to promote photon absorption and to compensate for the lower radiant energy. Therefore, when the integrated daytime carbon gain, leaf area and total leaf area per plant, which are the main factors determining the productivity of L. radiata var. radiata plant, were taken into account together, this species may be cultivated at about 60~70% of ambient irradiance to promote its growth.

Effects of Melatonin on Anti-oxidative Systems and Photosystem II in Cold-Stressed Rice Seedlings

“…After dark adaptation for 30 min, the fluorescence (F0), maximum fluorescence (Fm) and the non-photochemical quenching (NPQ) were determined (Zhou et al, 2010). The maximal quantum yield of PSII photochemistry in the dark-adapted state was calculated as Fv/Fm.…”

A new natural allotriploid, Lycoris × hubeiensis hybr. nov. (Amaryllidaceae), identified by morphological, karyological and molecular data

“…In this study, twenty quantitative characters were measured from each sample (Table 1). Eight leaf segments about 2 cm long from the central part of eight leaves (one leaf for each individual) were used for micromorphologic measurements, according to the methods of Zhou et al (2010). For all characters the values were the averages of the eight samples.…”

Effects of irradiance on the photosynthetic traits, antioxidative enzymes, and growth of Cryptotaenia japonica

“…Variable fluorescence (F v ) equals F m minus F 0 . The maximum quantum yield of PS II electron transport was calculated as F v /F m (Zhou et al 2010). …”

“…Plant height and stem diameter were measured with a ruler and a vernier caliper, and leaf area (LA) was determined using the grid method (1 × 1 mm). After the fresh masses of all samples were measured with electronic balances, they were dried in an oven at 80 °C for at least 72 h. Root mass per unit of total mass (root mass ratio, RMR), stem mass per unit of total mass (stem mass ratio, SMR), and leaf mass per unit of total mass (leaf mass ratio, LMR), leaf mass per unit leaf area (specific leaf mass, LMA), leaf area per unit of total mass (leaf area ratio, LAR), leaf water content (LWC), and root to shoot ratio were determined according to Zhou et al (2010).…”