Laurenţiu Filipescu Department of Technology of Inorganic Substances and Environmental Protection, Faculty of Applied Chemistry and Material S cience , University Politehnica of Bucharest, Phone: (021)4023885, e-mail: [email protected]A NEW CONCEPT CONCERNING THE FOLIAR FLUID FORMULATIONS International Conference On Chemistry And Chemical Engineering, Timisoara, 2008
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Laurenţiu Filipescu Department of Technology of Inorganic Substances and Environmental Protection, Faculty of Applied Chemistry and Material Science, University.
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Laurenţiu FilipescuDepartment of Technology of Inorganic Substances and Environmental Protection, Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, Phone: (021)4023885, e-mail: [email protected]
A NEW CONCEPT CONCERNING THE FOLIAR
FLUID FORMULATIONS
International Conference On Chemistry And Chemical Engineering, Timisoara, 2008
1.1. FOLIAR FLUIDSFOLIAR FLUIDS
Composition Composition
Foliar nutritive products are concentrated fluids containing particular components of the following classes of
chemical compounds:
• macronutrients (N+P+K),
• mezonutrients (Ca+Mg),
• micronutrients (B+Mo+Zn+Cu+Fe+Mn),
• biostimulants (organic substances promoting growth in crop size and quality)
• Fungicides (inorganic and organic substances providing protection against fungi and other fruit
diseases both during vegetative growth and post harvesting storage).
Required properties
1. complete solubility and chemical stability at higher concentrations as commercial product,
2. compatible in mixture with diluting hard waters as sprinkling solutions,
3. hiding power,
4. adherence,
5. penetration power through waxy cuticles, cell walls and plasma cell membrane,
6. moderate pH,
7. low saline and contact stress,
8. environmental friendliness.
DestinationDestination
Complementary nutrient sources associated with growth enhancers or pesticides available
and used in the most simple and efficient ways to handle crop control during any vegetative
development stage.
Formulation pitfalls Formulation pitfalls
Refining quality of foliar products according to the plant transient demands is confined to
restrictive limits due to objectionable changes in physical properties required for foliar application.
Most of the researches in the field of foliar fertilizers/foliar growth enhancers and pesticide were
focusing on active formulas in term of nutrient ratios and concentrations or biological active
components availability and phytotoxicity. The problems of foliar product penetration and uptake
yields, or formula efficiency were chiefly treated in terms of adjuvant adding to improve foliage
distribution or to ease application.
2. NEW FORMULATION APPROACH2. NEW FORMULATION APPROACH
This paper brings about a new concept for approaching foliar nutrition, taking the leaf cuticle
penetration mechanism as a keystone in formula design and product properties assessment. According
to this concept the new foliar fluids are concentrated emulsions containing two distinctive phases:
•an organic phase which is the carrier of growth enhancing and fungicide functions,
•an aqueous phase yielding all the mineral constituents of usual NPK liquid/foliar fertilizers with or
without micronutrients.
Both phases after dilution and hydrolysis are dispatching all the mineral/organic plant
nutritive/enhancing entities at a prerequisite level.
Original approach of the hydrolyzing emulsion application and leaf born nutritive species was
fulfilled with high regard to the permeation of the biological active entities through cuticle by both lipophilic
and polar paths of diffusion.
Consequently, the emulsion components selection has been made in good agreement with the
mass transport mechanism of lipophilic species through cutin wax domains (Buchholz and Schonherr
2000), as well as with high humidity/hydrolysis promotion at leaf surface in order to activate the cuticular
permeability to water and non lipophilic species (Schreiber 2005).
Reliable correlations composition – property were searched for finding adequate balances in
chemical formulation and foliar products required properties.
3. 3. CUTICULAR PENETRATION OF THE NUTRIENTCUTICULAR PENETRATION OF THE NUTRIENT
The foliar fluids applied on the aerial organs of plants have to penetrate three barriers:
a) waxy cuticle covering the epidermal cells or stomata walls;
b) epidermal cell walls; and
c) the epidermal cells plasma membrane.
Permeation of the active entities through cuticle occurs by the lipophilic and polar paths of
diffusion.
Permeation through the cell wall and plasma membrane occurs by active enzyme transport
and takes place only if cuticle resistance is subdued.
Both processes are highly dependent on fluid composition and on particular properties of the
Overbasic potassium salts of the naphthenic and oleic acids, picked up as intermediaries
bearing the physical and chemical properties matching the above selection criterion, are non-
crystalline materials with poor solubility in water. Meaningful overbasicity and additives choice may
produce aqueous emulsions/solutions of these salts bearing mandatory properties for foliar applied
fluids.
The use of ethanol as the third component in the pseudoternary system overbasic salts of
the naphthenic and oleic acids – water - ethanol is a good replacement for the random and mostly
insecure choice of other compatibility additives, because the miscibility water – ethanol and
ethanol – organic acids provides a convenient weight in handling the mixture properties and
shifting them to worthwhile values.
Pseudoternary liquid – liquid diagrams in systems overbasic naphthenate/oleate – water –
ethanol isotherms subsuming overbasicities from 2/1 to 6/1 are providing valuable information
about the balanced compositions which may carry demanded properties in both concentrated
emulsified fluids and diluted hydrolyzing solutions (figure 4).
Figure 4. Pseudo ternary systems overbasic potassium naphthenate – water – ethanol (a) and overbasic potassium oleate – water – ethanol (b) at 30ºC; Overbasicity 2/1, 4/1 and
6/1; Composition – surface tension diagrams.
Composition - property diagrams like these from figures 4 yield new data and leverage prospects due to
ethanol share in properties adjustment and control. Some other properties linked to fluids foliar
application may be disclosed by similar composition-properties diagrams as those presented in figure 4.
The initial assumptions on hydrolysis process originate from the workable step by step reaction
of carbonation with free air carbon dioxide, able to push the pH beyond a certain hydrolyzing point
and help adherent layers precipitation, while other species of nutritive compounds are nucleated from
diluted emulsion over hydrolyzing mass and grew as amorphous or poor crystallized phases.
The figures 5(a) and 5(a) illustrate the hydrolysis onset process going on at a pH dependent
dilution ratio of the overbasic naphthenate (molar ratio 4/1 and 1M), respectively potassium overbasic
oleate (molar ratio 4/1 and 1M) emulsions.
a b
Figure 5. Hydrolysis of potassium overbasic naphthenate (4/1) 1M(K) non pre-carbonated (a) and pre-carbonated up to pH 10 (b) during dilution with deionized water
Figure 6. Hydrolysis of potassium overbasic oleate (4/1) 1M(K) non pre-carbonated (a) and pre-
carbonated up to pH 10 (b) during dilution with deionized water
a b
Working on overbasiciy, carbonation degree and ethanol concentration seems to be a fair
reasonable way for control diluted spaying fluid pH.
Hydrolysate particles have a relative mobility on the leaf surface within applied fluid layer, from where
they canpenetrate liphophilic or polar pathways inside cuticle. Sooner or lather, due to liquid phase
evaporation, hydrolysate particles are entrapped into semisolid matrix layer and released during daily
rewetting and transpiration. Both spontaneous freshly hydrolyzed and terminating released size particle
are critical facing the depth cross through cuticle. In other words as small is the hydrolysate particle size
as large is its probability to penetrate either liphophilic or polar pathways. We assume the unexpected
magnitude in stimulative performances of these hydrolysable products is originating from the hydrolysate
capacity to use both liphophilic and polar pathways through cuticle.
0
20
40
60
80
100
120
140
160
180
0 10 20 30 40 50
Time, minutes
Mo
de,
nm K Naphthenate, dilution 1/25
K Naphthenate, dilution 1/200
K Oleate, dilution 1/25
K Oleate, dilution 1/200
Figure 5 shows that the one of the ranking feature of the
overbasic sold hydrolysates is the particle dominant dimension
(expressed by the mode of particle size distribution), which is
placed between 10 nm and 200 nm. Dominant particle size in
1/25 diluted overbasic oleate lays in the same interval as
dominant size in concentrated emulsions. For other dilutions this
significant parameters is displaced to higher dimensions and
eventually on higher dilutions hydrolysis products are flocculated.
Figure 8. Hydrolysate particle size in layered matrix
ExpectationsExpectations
The new class biological activities are extending over:
- dormant buds stimulation;
- ratio fruitlets/flowers;
- growth enhancing both in fruits and shoots;
- boosting crop and quality;
-promotion against fungi and other fruit diseases;
-extended protection against fungi and fruit diseases during the
long term storage.
CONCLUSIONSCONCLUSIONS
There was demonstrated the viability of a new way to formulated emulsified foliar fluids
on the grounds of prominent attributes originating from the mechanism and kinetics of
foliar absorption. The two liquid phase emulsions enable the implementation of
multifunctional biological performances and best control of the foliar properties. Also, a
new mechanics in the waxy cuticle penetration was provided through reactive
components hydrolysis, pH control and particle size distribution.
Selectiv literature citedSelectiv literature citedBuchholz A, Schonherr J, Thermodynamic analysis of diffusion of non-electrolytes across plant cuticles in the
presence and absence of the plasticiser tributyl phosphate. Planta 212, 2000, 103–111;Calogrea M., Chitu V., Chitu E., Filipescu L. “A new class of multifunctional foliar nutritive products”, Proc. of
13th Romanian International Conference on Chemistry and Chemical Engineering, Bucuresti, 2003;C. Cristea, M. Calogrea, M. Murgea, V. Chitu, L. Filipescu, Nutrinaft products and their fungicide effects,
Analele Universitatii din Craiova, vol. IX (XLV), 2004, 103; Chitu V. , E. Chitu, A. Hororoi, M. Calogrea, M. Murgea, L. Filipescu, Researches concerning Nutrinaft
products effects on apple production and fruit quality, Analele Universitatii din Craiova, vol. IX (XLV), 2004, 123Cirjaliu – Murgea M, Chitu V, Chitu E, Isopescu R Filipescu L Sequential Foliar Nutritive Fluids Design And
Foliar Absorption Mechanism 14th International Conference On Chemistry And Chemical Engineerig Proceegings Bucharest, Romania, 2005;
Downer JD Ragoonanan D Non-phytotoxic micronutrient composition US 4125395, 14 November 1978.Filipescu L. “Designing ecological products for agricultural uses” invited lecture University Venice, 2004; Filipescu L., Pincovschi E., Echilibrul solid-lichid, Ed. Tehnica Bucuresti, 1981.Koch K., Barthlott W., Koch S., Hommes A., Wandelt K., Mamdouh W., De-Feyter S., Broekmann P. 2006.
Structural analysis of wheat wax ( Triticum aestivum, c.v. ‘Naturastar’ L.): from the molecular level to three dimensional crystals. Planta, 223: 258-270.
Schreiber L.() Polar paths of diffusion across plant cuticles: New evidence for an old hypothesis. Annals of Botany 95(7), 2005, 1069–1073;
Schreiber L. Copermeability of 3H-labelled water and 14C-labelled organic acids across isolated Prunus laurocerasus cuticles: effect of temperature on cuticular paths of diffusion. Plant, Cell and Environment 25, 2002, 1087–1094;
Schreiber L, Effect of temperature on cuticular transpiration of isolated cuticular membranes and intact leaf disks. Journal of Experimental Botany 52, 2001, 1893–1900;
Schonherr J, Schreiber L., Size selectivity of aqueous pores in a stomatous cuticular membranes isolated from Populus canescens (Aiton) Sm leaves. Planta 219, 2004, 405–411;
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Acknowledgment
The work was carried out with the financial support of CNCIS, Program Idei, project