THE EFFECTS OF VAPOUR PRESSURE DEFICIT (VPD) AND ENRICHMENT WITH CO2 ON PHOTOSYNTHESIS, STOMATAL CONDUCTANCE, TRANSPIRATION RATE AND WATER USE EFFICIENCY (WUE) OF SWEET PEPPER (Capsicum annuum L.) GROWN BY NFT

1998 ◽  
pp. 351-356 ◽  
Author(s):  
A.W. Zabri ◽  
S.W. Burrage
2014 ◽  
Vol 94 (2) ◽  
pp. 303-310 ◽  
Author(s):  
Olanike Aladenola ◽  
Chandra Madramootoo

Aladenola, O. and Madramootoo, C. 2014. Response of greenhouse-grown bell pepper (Capsicum annuum L.) to variable irrigation. Can. J. Plant Sci. 94: 303–310. In order to optimize water use in bell pepper production information about the appropriate irrigation water applications and agronomic and physiological response to mild and severe water stress is necessary. Different water applications were tested on yield, quality and water stress threshold of greenhouse-grown bell pepper (Capsicum annuum L.) cultivar Red Knight in 2011 and 2012 on the Macdonald Campus of McGill University, Ste Anne De Bellevue, QC. The study was carried out on a soil substrate in the greenhouse. Irrigation was scheduled with four treatments:120% (T1), 100% (T2), 80% (T3), and 40% (T4) replenishment of crop evapotranspiration in a completely randomized design. The highest marketable yield, water use efficiency and irrigation water use efficiency were obtained with T1 in both years. T1 received 20% more water than T2 to produce 23% more marketable yield than T2. Fruit total soluble solids content was highest in T4, and smallest in T1. The mean crop water stress index (CWSI) of the irrigation treatments ranged between 0.08 and 1.18. Leaf stomatal conductance of bell pepper was 75 to 80% lower in T4 than in T1. Regression obtained between stomatal conductance and CWSI resulted in a polynomial curve with coefficients of determination of 0.88 and 0.97 in 2011 and 2012, respectively. The result from this study indicate that the yield derived justifies the use of an extra quantity of water. Information from this study will help water regulators to make appropriate decision about water to be allocated for greenhouse production of bell pepper.


2012 ◽  
Vol 39 (5) ◽  
pp. 366 ◽  
Author(s):  
J. G. Pérez-Pérez ◽  
I. C. Dodd ◽  
P. Botía

To determine whether irrigation strategy altered the sensitivity of Citrus leaf gas exchange to soil, plant and atmospheric variables, mature (16-year-old) Fino 49 lemon trees (Citrus limon (L.) Burm. fil. grafted on Citrus macrophylla Wester) were exposed to three irrigation treatments: control (irrigated with 100% of crop potential evapotranspiration, ETc), deficit irrigation (DI) and partial rootzone drying (PRD) treatments,which received 75% ETc during the period of highest evaporative demand and 50% ETc otherwise. Furthermore, to assess the physiological significance of root-to-shoot ABA signalling, the seasonal dynamics of leaf xylem ABA concentration ([X-ABA]leaf) were evaluated over two soil wetting–drying cycles during a 2-week period in summer. Although stomatal conductance (gs) declined with increased leaf-to-air vapour pressure deficit (LAVPD), lower leaf water potential and soil water availability, [X-ABA]leaf was only related to stomatal closure in well irrigated trees under moderate (<2.5 kPa) atmospheric vapour pressure deficit (VPD). Differences in [X-ABA]leaf were not detected between treatments either before or immediately after (<12 h) rewatering the dry side of PRD trees. Leaf water potential was higher in control trees, but decreased similarly in all irrigation treatments as daily LAVPD increased. In contrast, DI and PRD trees showed lower stomatal sensitivity to LAVPD than control trees. Although DI and PRD decreased stomatal conductance and photosynthesis, these treatments did not significantly decrease yield, but PRD increased crop water use efficiency (WUE) by 83% compared with control trees. Thus PRD-induced enhancement of crop WUE in a semiarid environment seems to involve physiological mechanisms other than increased [X-ABA]leaf.


2021 ◽  
Author(s):  
Fasih Ullah Haider ◽  
Muhammad Farooq ◽  
Muhammad Naveed ◽  
Sardar Alam Cheema ◽  
Noor ul Ain ◽  
...  

Abstract The synergistic effects of biochar and microorganisms on the adsorption of Cd and on cereal plant physiology remained unclear. Therefore, this experiment was performed to evaluate the combined effects of biochar pyrolyzed from (maize-straw (BC1), cow-manure (BC2), and poultry-manure (BC3), and microorganisms including (T. harzianum L. and B. subtilis L.), to evaluate, how incorporation of biochar positively influences microorganisms growth and nutrients uptake in plant, and how it mitigates under various Cd-stress levels (0, 10, and 30ppm). Cd2 (30 ppm) had the highest reduction in the intercellular CO2, SPAD value, transpiration rate, water use efficiency, stomatal conductance, and photosynthesis rate, which were 22.36, 34.50, 40.45, 20.66, 29.07, and 22.41% respectively lower than control Cd0 (0 ppm). Sole application BC, resulted in enhanced intercellular CO2, SPAD value, transpiration rate, water use efficiency, stomatal conductance, and photosynthesis rate were recorded in BC2, which were 7.27, 20.54, 23.80, 5.96, 13.37, and 13.50% respectively greater as compared to control and decreased the Cd-concentration in root and shoot of maize by 34.07 and 32.53%, respectively as compared to control. Similarly, among sole microorganism’s inoculation, minimized the Cd-concentration in shoot, root, and soil by 23.77, 20.15, and 10.35% respectively than control. These results suggested that integrated application of cow manure biochar BC2 and inoculation of microorganisms MI3 as soil amendments had synergistic effects in improving the adsorption of nutrients and decreasing the Cd-uptake in maize, and enhancing the physiology of plant grown in Cd-polluted soils as opposed to using either biochar or inoculating microorganisms alone.


2017 ◽  
Vol 47 (5) ◽  
Author(s):  
Márcia Vitória Santos ◽  
Evander Alves Ferreira ◽  
Daniel Valadão ◽  
Fabiana Lopes Ramos de Oliveira ◽  
Vitor Diniz Machado ◽  
...  

ABSTRACT: This study aimed to assess the effects of Eucalyptus and maize shading on characteristics related to water use by Brachiaria in agroforestry systems. Treatments were arranged in a split-split-plot design, with plots consisting of different spacing between Eucalyptus plants (12.0×2.0m and 12.0×4.0m), split-plots of different distances between Brachiaria and Eucalyptus (6.0, 4.0, and 2.0m), and split-split-plots of Brachiaria sowing sites (maize row and inter-row). One treatment with Brachiaria under full sunlight was included. Bread grass intercropping in maize inter-rows associated with the densest Eucalyptus spacing and bread grass proximity to Eucalyptus tree crowns adversely affected the stomatal conductance, internal carbon, and transpiration rate of bread grass. Water use efficiency of bread grass intercropped in maize rows decreased, regardless of the Eucalyptus plot design and distance between forages and trees.


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