Seasonal changes in photochemistry, light use efficiency and net photosynthetic rates of wild blueberry (Vaccinium angustifoliumAit.)

Abstract

Percival, D., Kaur, J., Hainstock, L. J. and Privé, J.-P. 2012. Seasonal changes in photochemistry, light use efficiency and net photosynthetic rates of wild blueberry (Vaccinium angustifolium Ait.). Can. J. Plant Sci. 92: 1135–1143. The seasonal variation of carotenoid concentration, chlorophyll a and b levels, dark- (Fv/Fm) and light-adapted (Fv′/Fm′) variable to maximal chlorophyll fluorescence (an indication of the quantum efficiency of PSII photochemistry) and net photosynthesis of the wild blueberry (Vaccinium angustifolium Ait.) was examined in the vegetative and cropping phases of production. Chlorophyll levels ranged from 2.0 to 12 µg cm−2 and from 0.042 to 1.4 µg cm−2 for chlorophyll a and b, respectively, were significantly lower in the cropping phase of production, and were also lower in the latter stages of the growing season. Similarly, carotenoid concentrations ranged from 0.67 to 4.1 µg cm−2 and were lower in the cropping phase of production. However, carotenoid concentration and dark- and light-adapted variable to maximal chlorophyll fluorescence (Fv/Fm and Fv′/Fm′) decreased marketably at the mid-point of the growing season, presumably as a result of photoinhibition. Net photosynthetic values of upright stems ranged from 2.1 to 7.6 µmol m−2 s−1, were substantially higher in the vegetative phase of production and also decreased significantly in the latter part of the growing season. Results from this investigation indicate that the wild blueberry has a relatively low photosynthetic rate, which may be prone to photoinhibition and limited carbohydrate supply (i.e., source) when compared with other temperate fruit crops.

Are Wild Blueberries a Crop with Low Photosynthetic Capacity? Chamber-Size Effects in Measuring Photosynthesis

“…The underestimation rate of stomatal conductance measurement using the big chamber was 52.2 ± 2.9% (Figure 3g,h). These results suggest that the photosynthetic rates of wild blueberries reported in the literature (Table 1; [16][17][18]) could also be underestimated as big leaf chambers were used [16][17][18]. Under saturated light, the photosynthetic rates of wild blueberries measured by the small leaf chamber could be as high as 16 µmol CO 2 m −2 s −1 with a mean of 11 µmol CO 2 m −2 s −1 , which is higher than those measured by the big leaf chamber and reported in the literature [16][17][18].…”

“…While photosynthesis measurements and modeling have been conducted extensively for various crops, only a few studies measured the photosynthesis of the wild lowbush blueberry crop (Vaccinium angustifolium Aiton) [16][17][18][19]. The wild blueberry crop is one of the most important crops in North America.…”

“…In previous studies that measured photosynthesis in wild blueberry plants during the vegetative year (Table 1; [16][17][18]) using a controlled leaf gas exchange system, big leaf chambers enclosing a stem with multiple leaves were used, as shown in Figure 1a. In this measurement process, the photosynthetic rate (CO 2 assimilation rate) needs to be corrected using the total leaf area of all the leaves inside that big leaf chamber.…”

Seasonal variation in non-structural carbohydrates, sucrolytic activity and secondary metabolites in deciduous and perennial Diospyros species sampled in Western Mexico

“…Testimony to its metabolic ubiquity, Suc can also act as a feedback regulator of photosynthetic activity and of sink-source relationships in plants. In such manner, Suc levels may determine phenologic variation of growth patterns, trigger negative feed-back loops that limit C assimilation rates and C availability for growth and development [ 5 ]. The above processes are central for the resolution of the constant conundrum faced by plants growing in a continuously changing environment, in which they must decide between employing costly C resources for growth and reproduction, or for survival under usually multiple, perduring and simultaneous (a)biotic stress conditions.…”

In situ estimation of foliar nitrogen in wild blueberry using reflectance spectra

“…Although not as effective as the green region, the VIS-range, Chl a, Chl b and Chl (a'b) regions yielded comparable results ( Table 2). The predictive ability of Chl a region was probably due to a higher proportion of Chl a in blueberry leaf tissues (Percival et al 2012), and a resulting stronger Chl a correlation with foliar N. Results from this study also indicate that foliar N could be accurately predicted using REPrange (R 2 00.71, RMSECV 00.23%) and NIR-plateau (R 2 00.81 and RMSECV 00.18%). Given that leaf water variations in NIR-plateau, we think that this good correlation simply results from the two proteinabsorbing bands centered at 910 nm and 1020 nm.…”