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EFFECT OF GASES ON YIELD AND QUALITY OF VEGETABLESSpeaker - Richa Naula Id.no. - 40100

What is a gas ?

A gas is a sample of matter that conforms to the shape of a container in which it is held and acquires a uniform density inside the container ,even in the presence of gravity and regardless of the amount of substance in the container.

Composition of Atmosphere

GASESCarbon dioxideNitrogen dioxideEthyleneOzoneSulfurdioxide

National ambient air quality standards given by CPCB(November,2009)

GasesTime weighted averageConcentration in ambient airIndustrial, residential, rural and other areaEcologically sensitive areaMicro gm/m3ppbMicro gm/m3ppbSulphur dioxideAnnual*501920824 hours**8030.48030.4Nitrogen dioxideAnnual*4021.23015.924 hours**8042.48042.4OzoneAnnual*100511005124 hours**18091.818091.8

** 24 hourly or 1 hourly monitored values as applicable shall be complied with 98% of thetime, 2% of the time, they may exceed the limits but not on two consecutive days ofmonitoring.* Annual arithmetic mean of minimum 104 measurement taken in a year at a particular sitetwice a week, 24 hourly at uniform levels.

Carbon dioxideCarbon dioxide is an essential component of photosynthesis.

The present concentration of CO2 in the atmosphere is increasing at the rate of 1.47 ppm/year ( Source-ESRL Global Monitoring Division).

AUGUST 2014397.01ppmSource- ESRL Global Monitoring DivisionAUGUST 2015398.92 ppmSource- ESRL Global Monitoring Division

Source-Energy Information Agency (Department of Energy)

Sources of Carbon Dioxide

IncreasedAutomobilesIndustrializationDeforestationPollution

Supplemental Source in Greenhouse

CO 2 generatorHot water boiler with condenserCO 2 condenser & blowerDistribution pipesDistribution in greenhouseDistribution in plants through clear Polythene tubes

Source-ESRL Global Monitoring Division

SourceESRL Global Monitoring Division

Estimates of Future Levels of CO2

IPCC, 2001

Effect of rise in CO2 on C3 & C4 plants

Photosynthesis increase (60-80%)Stomatal conductance decreases Transpiration reducesWUE increases (70%)

Kimball et al.,1993

Impact of elevated CO2 on growth, physiology, yield and quality of tomato cv. Arka Ashish under polyhouseCO2 (ppm)Plant height (cm)No. of leaves Leaf area (cm2 /p)No. of branches Leaf mass(mg/cm2)No. Of flower /pNo. Of fruits /pFruit set (%)Fruit yield (kg/p)

380(control)92.367.310,2009.54.6214045.832.82.49550115.080.816,60413.03.2517165.038.13.8470081.788.311,50217.35.3222795.842.25.61CD at 5%1.501.405.800.870.110.941.561.131.38

Mamatha et al., 2014

CO2 (ppm)PhenolsFlavanoidsAscorbic acidCarotenoidsLycopene TSS (0Brix)Acidity (%)38014.62.4812.423.215.13.500.445508.21.7916.023.815.43.450.3070012.42.3014.421.113.73.100.32CD at 5%0.3830.0550.2320.9840.6590.0940.033

Effect of elevated carbon dioxide on quality parametersMamatha et al., 2014

Photosynthesis and nutrient composition of spinach and fenugreek grown under elevated carbon dioxideParameterPlant40 DAEx60 DAEx80 DAEx350ppmA -CO2600 ppmE -CO2350ppmA -CO2600ppmE-CO2350ppmA-CO2600ppmE-CO2 Leaf area (cm2)Spinach495.74558.40610.52724.45732.45780.24Fenugreek166.60248.0220.50285.60247.30291.10PN (micro mol/m2/s1)Spinach13.0516.4012.6619.5215.7816.47Fenugreek9.7013.4511.2616.8110.4715.62Stomatal conductance g s (cm/s)Spinach0.890.841.050.910.730.69Fenugreek0.740.720.810.700.430.40

Jain et al., 2007

Effect on nutrient contentParameterPlant40DAEx60 DAEx80 DAExA-CO2E-CO2A-CO2E-CO2A-CO2E-CO2 C:N ratioSpinach12.7812.0817.5822.659.8013.82Fenugreek7.647.569.5210.625.929.17 Ca(microg/g)Spinach63.59 72.1363.0067.5855.0857.35Fenugreek18.5842.3240.5463.7045.9459.01Mg(microg/g)Spinach5.612.999.615.773.921.54Fenugreek4.161.457.264.263.602.55Fe(microg/g)Spinach11.095.0510.016.948.923.98Fenugreek3.572.396.813.594.632.89

Jain et al., 2007

Sulfur DioxideIt act as a nutrient in plants(at a conc. less than 18.5ppb) since sulfur is a required element for plant growth and development.

The plants have developed mechanisms that allow them to control the internal levels of sulfur obtained from soil or atmosphere (natural and anthropogenic sources).

Sources

Klimont et al.., 2012

Current Scenario

In 2010, India surpassed the United States as the worlds second highest emitter of sulfur dioxide (after China).Klimont et al.,2012

SO2 emission in IndiaSource Zifeng lu, 2013

Effect on plantsWhen 45 days old plants of tomato were exposed to 0.1 ppm of sulfur dioxide gas it was found that it increase the vegetative growth in the plant at the expense of reproductive growth (Pandey et al.,1995).Its main damage caused by its product sulfuric acid.It result in dry papery blotches that are generally white, tan or straw coloured.In some spp. chronic injury, causes brown to red blotches.

Contd....

Young and middle aged plants and leaves are sensitive.

Sensitivity is highest during day with bright Sunlight and high relative humidity.

Effect of sulfur dioxide pollution on the translocation and accumulation of heavy metals in soybean (Peijun et al., 2011)TreatmentsYield(g/plant)Plant dimension(cm)GrainTotal massPod skinLeafStemHeightDiameterInternodeControl SO2 (1.2 ppb)9.224.36.03.95.359.70.85.5Low SO2(97 ppb)8.821.95.43.34.352.50.75.2High SO2(490 ppb)6.718.65.03.03.847.40.64.4

Effect of SO 2 on average growth and production of soybean in metal control plants, i.e., plants grown in potting mixtures with no added heavy metals

Nitrogen DioxideThe uptake of nitrogen dioxide by plants occurs predominantly by foliar deposition.NO2 emissions over the Indian region are growing at an annual rate of 5.5% per year (Garg et al., 2001).Annual average NO2 concentrations varied from 4.3 to 42.9 ppb in various parts of the country (CPCB, 2009).

Contd....

At higher concentration, NO2 can cause acute injuries on plant leaves, while chronic exposure to lower concentration of NO2 reduces the growth of plants.In Haridwar ,India when wheat and mustard crops, were exposed to higher concentration of NO2 at the rate of 9 ppb showed maximum reductions in growth, yield, ascorbic acid content and photosynthetic pigments(Chauhan and Joshi , 2010).

Ozone (O3 )Ozone is a powerful oxidizing agent in a very dilute conc.(0.4 microl/l)Broccoli , Brussels sprouts , Cabbage , CarrotlowLow(0.01-0.02 microl/l)Cauliflower , cucumber , lettucelowHigh(0.03-0.1microl/l)Potato , SpinachlowHighAsparagus , Bean, Celery, BrinjallowMedium(0.04-0.2 microl/l)

Romero et al., 2007

Detrimental effects of ethylene related to quality in vegetablesEthylene effectsSymptoms / affected organCommodityReferencePhysiological disorderRusset spottingLettuceSalvador et al., 2003 and Pesis et al., 2002AbscissionBunchCherry tomatoBeno-Moualem et al., 2004StalkMuskmelonLima et al., 2004BitternessIsocoumarinCarrot , LettuceFan and Mattheis, 2000ToughnessLignificationAsparagusHennion et al., 1992SproutingTubers, BulbPotato, OnionWills et al., 2004; Benkeblia andSelselet-Attou, 1999ColourYellowingBroccoliSuzuki et al., 2004

Detrimental affects of ethylene

Avoiding Exposure to Ethylene

Removal of ethylene from storage rooms by-Use of ozone at conc. of 0.4microl/l was used to oxidize ethylene (Skog et al., 2001).1. O2 + UV O32. C2H4 + [O] CO2 + H2O

Avoiding Exposure to Ethylene Removal of ethylene from storage rooms by- Adequate ventilation (air exchange) . Ethylene absorbers: potassium permanganate (alkaline KMnO4 on inert pellets Ethysorb, etc . Use of low pressure (vacuum) system (i.e.hypobaric CA storage).

EFFECT OF GASES ON POST-HARVEST MANAGEMENT OF VEGETABLE CROPS

Gases used in post harvest managementIt is an asphyxiant and slightly corrosive in the presence of moisture.

It dissolves readily (1.57 g/ kg at 100 kPa, 20 C) in water to produce carbonic acid that increases the acidity of the solution and reduces the pH. This has significant implications for MAP of foods.Oxygen promotes several types of deteriorative reactions in foods including fat oxidation, browning reactions and pigment oxidation. Most of the common spoilage bacteria and fungi require oxygen for growth. To increase shelf life of foods the pack atmosphere should contain a low concentration of residual oxygen.

Carbon dioxideOxygen

Contd....Nitrogen does not support the growth of aerobic microbes and therefore inhibits the growth due to aerobic spoilage but does not prevent the growth of anaerobic microbes. The low solubility of nitrogen in foods can be used to prevent pack collapse by including sufficient nitrogen in the gas mix to balance the volume decrease due to carbon dioxide going into solution.Nitrogen

Controlled Atmosphere (CA)Reduction of oxygen and/or elevation of carbon dioxide concentration inside the storage chamber is maintained.

Retard ripening, respiration and senescence.Prolong shelf life Beneficial effect Prolonged storage life of perishable by arresting the respiration and senescence process.

Reduction in sensitivity to ethylene. Decrease in the incidence and severity of disease causing organism.

Inhibition of senescence and of ethylene effects by CA in parsley

Modify the concentration of gases in the produce packing. Reduce respiration rate.Reduce ethylene action.Delay ripening & senescence.Increase products shelf life.

O2

CO2

O2

CO2

21% O2 0.035%CO2Modified atmosphere (MAP)

Environment

Types of MAPIn this commoditys respiration characteristics are properly matched to film permeability values. If a film of correct intermediary permeability is chosen, then a desirable equilibrium modified atmosphere is established when the rates of O 2 and CO2 transmission through the package equal a products respiration rate.Replacing the package atmosphere with a desired mixture of CO2,O2 and N2 or the use of ethylene, CO2,O2 and N2 scavengers.E.g. Oxygen Absorber- Ferrous oxide and Iron Powder.Carbon dioxide absorber- Hydrated lime, Activated charcoal, Magnesium dioxide. Ethylene absorber- Potassium permangnet, Vermiculite etc.

PASSIVE MAPACTIVE MAP

VegetablesO2 CO2N2 Temp.Shelf lifeGreen asparagus10%5%85% 20C16-20 daysSea asparagus4%5%91%20C28-32 daysBroccoli3%8%89%30C35 daysCelery sticks6kPa7kPa-50C15 daysFresh cut peppers80/50kPa15kPa5/35kPa50C9-10 daysKhol Rabi5kPa10/15kPa80/85kPa50C14 days

Recommended gas mixture for MAP and its effect on storage life of vegetablesZhang et al., 2015

Effect of modified atmosphere packaging on quality changes of fresh Parsley, Spinach and Dill. In this vegetables were packaged in polyethylene pouches and were evaluated in three condition included perforated, modified atmosphere active, modified atmosphere passive at different temperature (5C, 10C, 20C, 25C).The following properties were determined vitamin C, chlorophyll, weight loss and total count. Results were indicated that storage of parsley in modified atmosphere active showed minimum loss weight and maximum chlorophyll retained. Parsley had the most moulds in perforated packages. However, maximum residual vitamin content was seen in MAP parsley.Masoud et al., 2011

Modified Atmosphere Packaging of precooked vegetables: effect on physicochemical properties and sensory quality (Barbosa et al., 2015)%O2 / %CO2Time (days)EC50(mg/ml)PHTotal colour change CFU/g0/40013.165.900.00< 101023.306.557.02< 101528.996.1116.98< 102035.385.7819.52>3.02.5/40013.165.900.003.02.5/60013.165.900.00