Nitrogen and Aeration Levels of the Nutrient Solution in Soilless Cultivation Systems as Important Growing Conditions Affecting Inherent Quality of Baby Leaf Vegetables: A Review (original) (raw)
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HortScience
The objective of this research was to study the effects of growing cycle (spring vs. winter) and nutrient solution aeration [no aeration (NA), low aeration (LA) or high aeration (HA)] on yield, quality, and on shelf life as a fresh-cut product of watercress grown in a floating system. The growing cycles lasted 25 days in spring and 39 days in winter. In the spring cycle, the plants had significantly higher yield and antioxidant capacity and lower specific leaf area, total root length, root diameter, length of 0 to 0.5 mm diameter root, and oxalate content than in the winter cycle. The absence of aeration increased the antioxidant capacity and vitamin C content in both cycles. Several adventitious roots developed exogenously from the watercress stem at the nodes as a morphological adaptation to oxygen depletion, particularly in NA conditions. The nitrate, oxalate, Ca2+, K+ contents, and microbial populations were affected by both the cycle and the aeration conditions. Hue angle of th...
Frontiers in Plant Science, 2021
Soilless cultivation systems are efficient tools to control nitrates by managing nutrient solution (NS) salinity and nitrogen availability, however, these nitrate-lowering strategies require appropriate calibration based on species/genotype-specific responses interacting with climate and growing conditions. Three experiments were carried out on lettuce and Cichorium endivia grown in ebb-and-flow (EF) and floating (FL) systems at two levels of NS salinity (EC = 2.5 and 3.5 dS m−1) (EC2.5, EC3.5, respectively) under autumn and early-spring (lettuce) and winter and late-spring conditions (C. endivia). Nitrogen deprivation (NS withdrawal a few days before the harvest) was tested at EC2.5, in the autumn and winter cycles. The EF-system caused an increase in salinity in the substrate where roots mainly develop so it mimicked the effect of the EC3.5 treatment. In the winter-grown lettuce, the EF-system or EC3.5 treatment was effective in reducing the nitrate level without effects on yield,...
Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 2021
Ammonium (NH4+) to nitrate (NO3-) ratio and growth media significantly alter plant development and NO3- accumulation in lettuce. Nitrate accumulation is regarded harmful for environment and human health. The quality of lettuce is assessed by NO3-concentration, size, and weight. This study determined the impact of five different growth media (cocopeat, peat, bark, perlite and rockwool) and four different NH4+:NO3- ratios (0:100, 20:80, 40:60 and 60:40) on NO3- accumulation in lettuce, yield, and several growth attributes. The experimentation was conducted according to open feeding system of soilless agriculture. The ‘Cosmos’ variety of lettuce was used as experimental material in the study. Growth mediums and NH4+:NO3- ratios significantly altered NO3- accumulation, head, leaf, stem and root traits. The results revealed that instead of growing lettuce with NO3- only in peat and rockwool, addition of NH4+ (20:80 of NH4+:NO3-) into nutrient solution increased head weight. While head we...