scholarly journals Leaf gas exchange and chlorophyll index in guava fertirrigated with bovine biofertilizer and nitrogen

2020 ◽  
Vol 9 (9) ◽  
pp. e588997606
Author(s):  
Elisson Alves Santana ◽  
Francisco Eduardo dos Santos Gomes ◽  
Jackson Teixeira Lobo ◽  
Alberto de Andrade Soares Filho ◽  
Ítalo Herbert Lucena Cavalcante ◽  
...  

The objective of this work was to evaluate the influence of fertirrigation with nitrogen and liquid bovine biofertilizer on gas exchange and leaf chlorophyll index of 'paluma' guava (Psidium guajava L.). The experimental design was randomized blocks with treatments distributed in a factorial arrangement (2 × 4) referring to mineral fertilizing with N (50% and 100% of N recommended) and biofertilizer concentrations (0, 2.5, 5.0 and 7.5% of the fertirrigated volume). Variables evaluated were chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll indexes (Chltotal), internal CO2 concentration (Ci), stomatal conductance (gs), transpiration (E), net photosynthesis (A), instant carboxylation efficiency (iCE) and water use efficiency (WUE). The biofertilizer significantly affected Chl a, Chl b, Chltotal, A, gs and E, with quadratic polynomial adjustment of the results. However, there was no effect of N fertilization and interaction between the factors. Maximum index of Chltotal was 32.31 obtained with the estimated dose of 3.8% of the biofertilizer; while A, gs and E presented maximum responses of 19.09 µmol of CO2 m-2 s-1, 0.28 mol of H2O m-2 s-1 and 4.93 mmol of H2O m-2 s-1, with estimated doses of 3.6%, 3.6%, and 3.7%, respectively. Generally, liquid bovine biofertilizer applied via fertirrigation affects positively the photosynthetic responses in 'paluma' guava, however, with decreasing effects for doses above 3.8%.

2017 ◽  
Vol 47 (3) ◽  
pp. 345-352
Author(s):  
Álvaro Henrique Cândido de Souza ◽  
Roberto Rezende ◽  
Marcelo Zolin Lorenzoni ◽  
Fernando André Silva Santos ◽  
André Maller

ABSTRACT Adequate crop fertilization is one of the challenges for agriculture. Measuring gas exchange and biomass accumulation may be used to adjust crop management. The effect of fertigation with potassium (0 kg ha-1, 54 kg ha-1, 108 kg ha-1 and 216 kg ha-1) and nitrogen (0 kg ha-1, 67 kg ha-1, 134 kg ha-1 and 268 kg ha-1) on gas exchange and biomass accumulation in eggplant was assessed under greenhouse conditions. The net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, instantaneous carboxylation efficiency, water-use efficiency and total dry weight were evaluated. With the exception of K for water-use efficiency and N for internal CO2 concentration, all the other gas exchange parameters were significantly affected by the K and N doses. There was an interaction between N and K doses for net photosynthesis, stomatal conductance, transpiration and instantaneous carboxylation efficiency. The highest values for net photosynthesis, stomatal conductance, transpiration rate, carboxylation instantaneous efficiency and total dry weight were found in the range of 125-185 kg ha-1 of K and 215-268 kg ha-1 of N.


Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 663
Author(s):  
James Bunce

Attempts to identify crop genetic material with larger growth stimulation at projected elevated atmospheric CO2 concentrations are becoming more common. The probability of reductions in photosynthesis and yield caused by short-term variation in CO2 concentration within elevated CO2 treatments in the free-air CO2 enrichment plots raises the question of whether similar effects occur in glasshouse or indoor chamber experiments. These experiments were designed to test whether even the normal, modest, cyclic variation in CO2 concentration typical of indoor exposure systems have persistent impacts on photosynthesis and growth, and to explore mechanisms underlying the responses observed. Wheat, cotton, soybeans, and rice were grown from seed in indoor chambers at a mean CO2 concentration of 560 μmol mol−1, with “triangular” cyclic variation with standard deviations of either 4.5 or 18.0 μmol mol−1 measured with 0.1 s sampling periods with an open path analyzer. Photosynthesis, stomatal conductance, and above ground biomass at 20 to 23 days were reduced in all four species by the larger variation in CO2 concentration. Tests of rates of stomatal opening and closing with step changes in light and CO2, and tests of responses to square-wave cycling of CO2 were also conducted on individual leaves of these and three other species, using a leaf gas exchange system. Reduced stomatal conductance due to larger amplitude cycling of CO2 during growth occurred even in soybeans and rice, which had equal rates of opening and closing in response to step changes in CO2. The gas exchange results further indicated that reduced mean stomatal conductance was not the only cause of reduced photosynthesis in variable CO2 conditions.


2014 ◽  
Vol 60 (No. 6) ◽  
pp. 274-279 ◽  
Author(s):  
A. Nasraoui-Hajaji ◽  
H. Gouia

N-fertilization type affected differently tomato growth. In the field experiment, hydroponic cultures were conducted using NO<sub>3</sub>-N (5 mmol); mixture of KNO<sub>3</sub>-N (3 mmol) and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>-N (2 mmol); NH<sub>4</sub><sup>+</sup>-N (5 mmol) or urea&nbsp;(5 mmol) as nitrogen source. Compared to nitrate, ammonium and urea had negative effects on morphology and dry matter production. Effects of the different nitrogen forms were investigated by measuring several photosynthesis parameters and chl a fluorescence. Two different significant types of reaction were found. When nitrogen was added as ammonium or urea, dry weight, chlorophyll tenor, transpiration rate, stomatal conductance and photosynthetic activity were inhibited. Supply of ammonium or urea, reduced the ratio (F<sub>v</sub>/F<sub>m</sub>), photochemical quenching and enhanced the non photochemical quenching. These data suggest that the adverse decrease in tomato growth under ammonium or urea supply may be related principally to inhibition of net photosynthesis activity. The high non photochemical quenching shown in tomato fed with ammonium or urea indicated that PS II was the inhibitory site of NH<sub>4</sub><sup>+</sup>-N which was directly uptaken by roots, or librated via urea hydrolysis cycle.


2010 ◽  
Vol 40 (6) ◽  
pp. 1290-1294 ◽  
Author(s):  
Inês Cechin ◽  
Natália Corniani ◽  
Terezinha de Fátima Fumis ◽  
Ana Catarina Cataneo

The effects of water stress and rehydration on leaf gas exchange characteristics along with changes in lipid peroxidation and pirogalol peroxidase (PG-POD) were studied in mature and in young leaves of sunflower (Helianthus annuus L.), which were grown in a greenhouse. Water stress reduced photosynthesis (Pn), stomatal conductance (g s), and transpiration (E) in both young and mature leaves. However, the amplitude of the reduction was dependent on leaf age. The intercellular CO2 concentration (Ci) was increased in mature leaves but it was not altered in young leaves. Instantaneous water use efficiency (WUE) in mature stressed leaves was reduced when compared to control leaves while in young stressed leaves it was maintained to the same level as the control. After 24h of rehydration, most of the parameters related to gas exchange recovered to the same level as the unstressed plants except gs and E in mature leaves. Water stress did not activated PG-POD independently of leaf age. However, after rehydration the enzyme activity was increased in mature leaves and remained to the same as the control in young leaves. Malondialdehyde (MDA) content was increased by water stress in both mature and young leaves. The results suggest that young leaves are more susceptible to water stress in terms of gas exchange characteristics than mature leaves although both went through oxidative estresse.


2018 ◽  
Vol 10 (6) ◽  
pp. 171
Author(s):  
João Everthon da Silva Ribeiro ◽  
Arliston Pereira Leite ◽  
José Eldo Costa ◽  
Manoel Bandeira de Albuquerque ◽  
Fábio Mielezrski

Among nutrients, nitrogen is required in the greatest quantities by bean culture. The objective of this work was to evaluate growth, physiological responses and productivity of the common bean cultivar, ‘IAC Imperador’ under varying nitrogen doses in Brejo Paraibano. The experiment was carried out at Fazenda Experimental Chã-de-Jardim (Chã-de-Jardim Experimental Farm), of the Centro de Ciências Agrárias of the Universidade Federal da Paraíba, in the municipality of Areia, state of Paraíba. The treatments comprised 0, 50, 100, 150 and 200 kg of nitrogen ha-1, applied in coverage at 35 days after sowing. To assess growth, plant height, stem diameter and number of leaves were evaluated. For gas exchange, photosynthesis rate, internal CO2 concentration, transpiration, stomatal conductance, instantaneous water use efficiency and instantaneous carboxylation efficiency were evaluated. For chlorophyll “a” fluorescence, minimum leaf fluorescence, maximum leaf fluorescence, variable maximum fluorescence, potential quantum efficiency of PSII (Photosystem II) and ratio (Fv/F0) were evaluated. For the components of primary productivity, the height of insertion of the first pod, number of pods per plant and the number of grains per pod were evaluated. Nitrogen fertilization in coverage significantly affected most of the growth, gas exchange and productivity variables, with the dose of 200 kg ha-1 being responsible for the highest values (p < 0.05). Chlorophyll fluorescence showed no significant differences among the nitrogen doses. The nitrogen doses influenced the growth, gas exchange and productivity of the common bean in the region of Brejo Paraibano. 


2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 1377-1381 ◽  
Author(s):  
J. P. Privé ◽  
L. Russell ◽  
A. LeBlanc

A field trial was conducted over two growing seasons in a Ginger Gold apple orchard in Bouctouche, New Brunswick, Canada to examine the impact of Surround (95% kaolin clay) on leaf gas exchange [net photosynthesis (Pn), stomatal conductance (gs), intercellular CO2 (Ci) and transpiration (E)]. In 2004, a greater rate of Pn and gs was achieved at the higher than at the lower frequency of Surround applications. This was particularly notable at leaf temperatures exceeding 35°C. In 2005, no significant (P ≤ 0.05) differences among leaf residue groupings [Trace (< 0.5 g m-2), Low (0.5 to 2 g m-2), and High (≥ 2 g m-2)] were found for the four leaf gas exchange parameters at leaf temperatures ranging from 25 to 40°C. It would appear that under New Brunswick commercial orchard conditions, the application of Surround favours or has no effect on leaf gas exchange. Key words: Surround, particle film, leaf physiology, photosynthesis, stomatal conductance, intercellular CO2, transpiration


2015 ◽  
Vol 105 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Sandro Dan Tatagiba ◽  
Fábio Murilo DaMatta ◽  
Fabrício Ávila Rodrigues

This study was intended to analyze the photosynthetic performance of rice leaf blades infected with Monographella albescens by combining chlorophyll (Chl) a fluorescence images with gas exchange and photosynthetic pigment pools. The net CO2 assimilation rate, stomatal conductance, transpiration rate, total Chl and carotenoid pools, and Chl a/b ratio all decreased but the internal CO2 concentration increased in the inoculated plants compared with their noninoculated counterparts. The first detectable changes in the images of Chl a fluorescence from the leaves of inoculated plants were already evident at 24 h after inoculation (hai) and increased dramatically as the leaf scald lesions expanded. However, these changes were negligible for the photosystem II photochemical efficiency (Fv/Fm) at 24 hai, in contrast to other Chl fluorescence traits such as the photochemical quenching coefficient, yield of photochemistry, and yield for dissipation by downregulation; which, therefore, were much more sensitive than the Fv/Fm ratio in assessing the early stages of fungal infection. It was also demonstrated that M. albescens was able to impair the photosynthetic process in both symptomatic and asymptomatic leaf areas. Overall, it was proven that Chl a fluorescence imaging is an excellent tool to describe the loss of functionality of the photosynthetic apparatus occurring in rice leaves upon infection by M. albescens.


2020 ◽  
Author(s):  
Wellington L Almeida ◽  
Rodrigo T Ávila ◽  
Junior P Pérez-Molina ◽  
Marcela L Barbosa ◽  
Dinorah M S Marçal ◽  
...  

Abstract The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and metabolism are affected in coffee (Coffea arabica L.) trees by drought and fruiting. Field-grown plants were irrigated or not, and maintained with full or no fruit load. Under mild water deficit, irrigation per se did not significantly impact growth but markedly reduced branch mortality in fruiting trees, despite similar leaf assimilate pools and water status. Fruiting increased net photosynthetic rate in parallel with an enhanced stomatal conductance, particularly in irrigated plants. Mesophyll conductance and maximum RuBisCO carboxylation rate remained unchanged across treatments. The increased stomatal conductance in fruiting trees over nonfruiting ones was unrelated to internal CO2 concentration, foliar abscisic acid (ABA) levels or differential ABA sensitivity. However, stomatal conductance was associated with higher stomatal density, lower stomatal sensitivity to vapor pressure deficit, and higher leaf hydraulic conductance and capacitance. Increased leaf transpiration rate in fruiting trees was supported by coordinated alterations in plant hydraulics, which explained the maintenance of plant water status. Finally, by preventing branch mortality, irrigation can mitigate biennial production fluctuations and improve the sustainability of coffee plantations.


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