Measurement of physiological traits can be used to monitor plant water status, for irrigation scheduling or to predict the expected yield in open-field production of vegetables. This study evaluates the changes in stomatal conductance, chlorophyll fluorescence (Fv/Fm), relative chlorophyll content (SPAD), and canopy temperature at different stages of development of processing tomato to show their relationships with the yield and quality under well-irrigated, deficit irrigated, and non-irrigated conditions. Under non-irrigated conditions, during flowering with fruit setting and early fruit development the highest canopy temperature, lowest stomatal conductance, and Fv/Fm were measured, while the SPAD value was the highest. Under this condition, the correlation between the SPAD value, fruit weight, and marketing yield was positive, but it was negative with the total soluble solid (°Brix). During flowering with fruit setting, under deficit irrigation conditions a close significant positive correlation was found between the SPAD value and the fruit weight, marketing yield, and vitamin C content of fruits. During this period, under regularly irrigated conditions, the SPAD, Fv/Fm, and canopy temperature related to stomatal conductance. Stomatal conductance had significant influence on yield and quality under non-irrigated and well-irrigated conditions while the SPAD value and canopy temperature had significant influence on under deficit irrigated conditions.

Water supply is a primary contributor to the growth and phytonutrient composition in chili peppers. Several physiological stress factors can influence phytonutrients in chili peppers, resulting in their differential synthesis. Maintaining the right and exact amount of water through a drip system can promote an effective fruit set and crop quality. Four pepper cultivars (‘Hetényi Parázs’; HET, ‘Unikal’; UNIK, ‘Unijol’; UNIJ and ‘Habanero’; HAB) were investigated under different water supply treatments: RF or rain-fed, DI or deficit irrigation, and OWS or optimum water supply. The two-year experiment was carried out in May 2018 and 2019 under open field conditions. Physiological parameters (relative chlorophyll content, chlorophyll fluorescence, and canopy temperature) were measured during the growth stage and phytonutrients (vitamin C, capsaicinoids and carotenoids) analyzed using high-performance liquid chromatography (HPLC) at harvest in September. The study revealed that, due to higher precipitation and rainfall interruption, increased water supply affected physiological response and phytonutrients in the cultivars. HAB under OWS had a lower response during the growth period when compared to HET, UNIK, and UNIJ. As water supply increased, measured individual carotenoid concentration increased in some cultivars. On the other hand, as water supply decreased, vitamin C and capsaicinoids concentration increased. Even though cultivars responded to the water supply treatments differently, HET exhibited a more uniform and stable composition in all treatments.

Mycorrhizal inoculations were investigated to reveal their effects on the growth and productivity of processing tomato grown under field conditions. Plants inoculated at sowing (M1), sowing + transplanting (M2) and non-inoculated plants (M0) were grown under regularly irrigated (RI), deficit irrigated (DI), and non-irrigated (I0) conditions. In dry years, under non-irrigated conditions (M2) treatment significantly decreased the canopy temperature, improved the photosynthetic efficiency expressed by chlorophyll fluorescence (Fv/Fm) and the fruit setting, significantly increased the total carotenoids and lycopene concentration of fruits but increased the ratio of green yield. Using deficit irrigation, (M2) plants produced more and larger weighed red fruits than (M1) plants but the β carotene, lutein and lycopene concentration of fruits, except for the vitamin C, decreased. Under severe drought conditions the mycorrhizal inoculations positively influenced the all carotenoids and lycopene concentration of fruits (r = 0.8150, r = 0.7837), but their impact was negative under deficit irrigation. Under water deficiency (I0, DI) the mycorrhizal symbiosis increased the marketable yield and resulted in a 33% increase in green yield and an 18 % increase in the total carotenoids content in dry years but the unmarketable yield decreased. Under water deficiency (M2) treatment produce more marketable yield resulting in 9.8% higher total carotenoids in the tomato fruits than (M1) treatment under field conditions.

Changes in total phenolic content (TP) and total antioxidant capacity (AC) during the vegetation period (April-November) were analysed in Phyllostachys aureosulcata f. aureocaulis (PAA), P. flexuosa (PF), P. humilis (PH), P. sulphurea var. sulphurea (PSS). Different extraction methods were compared: infusion or decoction with water or aqueous methanol. The highest significant value for TP was measured in the case of infusion at 90 °C for 5 min, which lead to the highest value for AC. During the vegetation period the highest values of TP were measured in April and May in the case of PAA (409.5; 314.9 and 258.7; 119.0 μg GA/ml) and PH (388.4; 411.6 and 252.9; 253.3 μg GA/ml). There was a clear trend in the changes of TP, with high values in April and November and a peak during August-September. Similar to TP, the highest values of AC were measured in April and May in PH (519.7; 566.3 and 513.5; 510.4 μg AA/ml) and PAA (534.5; 337.8 and 394.9; 275.4 μg AA/ml). We compared the change of TP in all taxa with stress index values derived from daily maximum and minimum air temperature, cumulative precipitation plus irrigation and cumulative evapotranspiration values. A close correlation R² = 0.32 (p=0.001) was found between stress index values and the change in TP of all taxa. The correlation is even closer R² = 0.52 (p=0.001) with PF, PH and PSS. Our results with PAA can be explained by possible inter/intra-specific differences in freeze tolerance and cold-acclimation.

Total phenolic content (TP) and total antioxidant capacity (AC) were analysed in shoots of Phyllostachys aureosulcata (PA), P aureosulcata f. aureocaulis (PAA), P. aureosulcata f. spectabilis (PAS), P. bissetii (PB), P. flexuosa (PF), P. humilis (PH), P. iridescens (PI), P. nigra var. nigra (PNN), P. nigra var. henonis (PNH), P. mannii (PM), P. sulphurea var. sulphurea (PSS), P. violascens (PVI), P. viridiglaucescens (PVG), P. vivax f. aureocaulis (PVA), collected on four harvest dates. Both TP and AC were determined following three processing methods, fresh, boiled and pickled in shoots of PF. Comparative study of TP and AC in the above Phyllostachys species shoots has not been reported before. The highest TP (1,227.6 μg GA/ml) and AC (154.0 μg AA/ml) values were measured in fresh shoots and the lowest in pickled ones. The highest values of TP were measured in the case of PA (1,321.95 μg GA/ml). The other taxa followed in decreasing order: PF, PVI, PI, PAA, PB, PAS, PNN, PNH, PM, PH, PSS and PVA. The highest AC values were obtained in the case of PI (184.24 μg AA/ml). The other taxa followed in decreasing order: PA, PF, PSS, PNN, PNH, PVG, PB, PAA, PAS, PV, PVA, PM and PH. The highest TP values were measured in taxa harvested on the first collection date and the values consequently decreased in taxa collected at later harvest dates. Our findings suggest that the earlier harvest date, through the influence of lower temperatures, could enhance the phytochemical content of bamboo shoots.