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Phosphorous and Potassium (PK, Potash etc)

 

PK BENEFITS

 

  • Increased density and weight (Yield)
  • Increased essential oil production
  • Sweeter tasting fruit
  • Increased flowering sites

 

Potassium and phosphorous are important elements in flowerset. By providing increased amounts of potassium and phosphorous to the plant at the right times it is possible to optimize flower growth and essential oil/resin production.

 

Potassium

 

Potassium is used in large quantities by plants to maintain ion balances within the cells, maintain osmotic pressure throughout the plant and activate enzymes; it is also required for protein synthesis. Potassium is the most important element in flower and fruit development.

 

Phosphorous

 

Phosphorus plays an essential role in photosynthesis; it helps with the formation of oils and helps convert light energy into chemical energy, resulting in optimum plant maturation and development. Phosphorous effects rapid growth and encourages bloom.

 

This said…

 

PK Additives and The High P Myth – The Overuse of Phosphorous in Hydroponics

 

It has been shown that phosphorous (P) is possibly overused by many hydroponic growers. Tissue tests conducted in 2003 by Advanced Nutrients through BC Research Inc on numerous cannabis strains demonstrated that cannabis plants require far less P than is present in many hydroponic nutrient formulations and additives. The tissue tests also demonstrated that N, Ca and K are required at far higher levels than P and P, while required at somewhat higher levels in bloom than grow (as is shown in numerous studies), is required at far lower levels than would be expected. Another surprising outcome was N requirements in flower (re cannabis) were higher than previously believed. These findings contradicted conventional beliefs among hydro industry professionals and others that high levels of phosphorous are required to achieve optimal flowerset in hydroponic settings (among other things). 1

 

In recent trials conducted by several US based medical growers, it was shown that optimal P levels in DTW/RTW coco were at approximately 60ppm during mid to late bloom. This figure was shown to be similar in soils – with as low as 40ppm of P in soil producing extremely good results.

 

While these trials lacked what would be considered standard scientific qualitative checks and measures (eg. no control was used to measure outcomes with higher and lower ranges of P in side-by-side trials) what became apparent over several months and several crop cycles was, 1) low P in solution (approx 20-25ppm) helped to reduce stretch and shorten internode gaps (setting up better plant structure) during the first weeks of the 12/12 flower cycle, 2) no yield benefits were obtained above 60ppm P and 3) resin production was optimal at 60ppm of P and seemed unaffected at even lower levels in both soil and coco (<40ppm). 2

 

Similar findings with tomato crops grown in soilless culture support these findings.

 

According to Spensley et al.,3 a typical nutrient solution for tomato production has the following composition: N: 150-200 ppm, P: 30- 40 ppm, K: 200-300 ppm, Mg: 40-50 ppm, Ca: 150-200 ppm and Fe: 5 ppm. Moreover, Winsor and Massey noticed that yield of tomato fruit was reduced significantly by low potassium concentration. 4

 

What these findings suggests is that many manufacturers of hydroponic nutrients and additives have their NPK profiles wrong and that an optimized PK additive should contain higher levels of K to P than is typically found in the vast majority of Potash products.

 




Coco Veg and Bloom Formula’s (Based on the Research of Yosemite Sam, IC Mag)


Coco Veg

150-24-150-166-70-25

N-P-K-Ca-Mg-Si

 

Coco Bloom 

110-60-175-160-65-25

N-P-K-Ca-Mg-Si

 

Keep in mind that coco substrate requires higher levels of Ca and Mg than inert mediums so these numbers would differ from a formula developed for water based systems and/or inert medias such as rockwool. Factors such as genetics, crop type, growing method etc will  also play an important role in an optimized nutrient regime.

 


 

Evaluation of P in Hydroponic Working Solutions

 

We evaluated several off the shelf hydroponic nutrients at the same dilution rates to establish how many ppm of P (phosphorous) would be in working solution by average. The aim of the analysis was to establish roughly what ppm of P would be in working solution across a broad range of ECs as different nutrient brands are more concentrated than others and this reflects in EC at equivalent dilution rates. In all cases ppm of P equaled or exceeded 60ppm. The ppm data was calculated from lab analysis of concentrate formulas once diluted.

 

Samples (elemental P and not P as P2O5)

 

AN Sensi Bloom 4ml/L = 81ppm P

AN Connoisseur Bloom 4ml/L = 90ppm P

H and G Coco 4ml/L = 60ppm P

Canna Coco 4ml/L = 64ppm

Canna Aqua Flores 4ml/L = 60.8ppm P

 

When considering that many hydroponic growers use further P through the use of P and K additives during flowerset this too needs to be factored into the P equation. For instance, with a product that contained PK 13- 14 %w/w listed as P2O5 and K2O with a specific gravity of 1.25, used at 1.5mL/L this would equate to an additional 104.8ppm of P in working solution. This would mean that if you were using eg. Canna Coco nutrient at 4ml/L and our example PK 13-14 at 1.5ml/L there would be approximately 168ppm of P in solution – or approximately three times the required levels of P that are optimal for coco substrate growing.

 

The Problem with Excessive Phosphorous in Solution

 

High levels of a particular nutrient can interfere with the availability and uptake of other nutrients. The nutrients which interfere with one another are referred to as antagonistic.

 

Excessive phosphorus will reduce the availability of iron, calcium, potassium, nitrogen, copper, and zinc. This is particularly true of the microelements iron, and zinc.

 

What this means is that the overuse of phosphorous in solution will starve out other important nutrients that are required for healthy growth/optimal yields.

 


 

Iron

Iron has special importance in biological redox systems involved with chlorophyll formation and protein synthesis.

 

Iron is essential in the enzyme system in plant metabolism (photosynthesis and respiration).

 

The enzymes involved include catalase, peroxidase, cytochrome oxidase, and other cytochromes. Fe is part of protein ferredoxin and is required in nitrate and sulfate reductions.

 

Fe is essential in the synthesis and maintenance of chlorophyll in plants and has been strongly associated with protein metabolism.

 

Zinc

 

Zinc is an integral component of many enzymes. Zinc plays a major role in protein synthesis and is involved with the carbohydrate metabolic processes. Zinc is also required for maintaining integrity of biomembranes and protecting membranes from oxidative damage from toxic oxygen radicals.

 

Zinc is important in the formation of the growth hormone auxin. Auxin is produced by shoot tips, and controls cell division, leaf and shoot growth and fruit development.

 

Zinc is also needed by leaf cells to form the green leaf pigment chlorophyll. Chlorophyll is needed for leaves to make sugars (photosynthesis).

 

Trace elements such as zinc are only needed in small quantities, but when they are in short supply, serious problems can occur.

 

Severely affected plants develop small, misshapen fruits of poor quality. This is due to poor cell division early in fruit development, and fruits not getting enough sugars from photosynthesis.

 


 

Other than this…

 

Phosphorous in Combustible Crops

 

Burning phosphorus with sufficient oxygen results in the formation of phosphorus pentoxide (P4O10 but often simplified to P2O5 due to this being the simplest molecular breakdown of P pentoxide).

 

Phosphorus pentoxide is an irritant to the skin, mucous membranes, and respiratory tract/system (lungs etc) even at concentrations as low as 1 mg/m3. What this means in simple terms is that if phosphorous is present in a combustible crop (after drying and curing) the produce when ingested, via inhalation, will be harsh and chemically tasting. This may have health implications on the end user if they are ingesting phosphorus pentoxide on a regular basis.

 

High End PK Additive Formulations

 

It’s worth noting that sulfur (S) as well as magnesium (Mg) and ammonium nitrogen (NH4N) are also in demand by the plant during flowering.

 

In short…

 

Magnesium activates the plant enzymes needed for growth. Additional Mg in flowerset can prove beneficial to yields.

 

Low levels of ammonium nitrogen (NH4N) can be beneficial for increasing flowering sites and yield weights in some flowering/fruiting crops (eg. tomatoes).

 

Sulfur plays a key role in plant metabolism and is a molecular building block for a number of proteins, hormones and vitamins. Rapidly growing plants can gain from additional S in nutrient and additive formulations.

 

For this reason a premium/optimal Potash product should contain Mg, NH4N, and S, along with high levels of potassium and much lower levels of phosphorous.

 

Refs

  1. Advanced Nutrients. The Great Phosphorous Myth Exposed.
  2. IC Mag. The myth, of the high P myth. Trials conducted by Yosemite Sam, Spurr, and others.   http://www.icmag.com/ic/showthread.php?t=191007
  3. Spensley K., Winsor W., Cooper J., Nutrient film technique-crop production in flowing nutrient solution, Outlook of Agriculture (1978)
  4. Majid FANDI*, Jalal MUHTASEB**, and Munir HUSSEIN (2010) EFFECT OF N, P, K CONCENTRATIONS ON YIELD AND FRUIT QUALITY OF TOMATO (SOLANUM LYCOPERSICUM L.) IN TUFF CULTURE

 

Triacontanol

 

Triacontanol (TRIA) has been realized as a potent plant growth promoting substance for a number of agricultural and horticultural crops.1

 

Triacontanol can be applied to the plant during any stage of growth, from seed or cutting to harvest day. Triacontanol is non-toxic to plants, animals, and humans at all levels within reason and is safe to use on consumable crops. Triacontanol can be co-applied with Auxins, Gibberellins, Cytokinins, and Brassinosteroids.

 

The Science

 

1-Triacontanol is a fatty alcohol of the general formula C30H62O, also known as melissyl alcohol or myricyl alcohol. It is found in plant cuticle waxes and in beeswax. Triacontanol is a plant growth regulator in the subclass of “growth stimulant” shown to increase yields in many plants, most notably C3 plants. 2

 

C3 plants include wheat, rice, daisies, petunias, roses, fruit trees, conifers and cannabis. ALL C3 plants can benefit from TRIA applications, regardless of growing style or environmental conditions, although different types of C3 plants will have different optimum dosage rates of TRIA. Many investigators have shown that TRIA affects several basic metabolic processes including photosynthesis, nutrient uptake, and enzyme activity. 3

 

Triacontanol has shown the ability to (somewhat) alleviate negative effects of stress induced by salinity toxicity, cold temperatures, and CO2 and light deprivation.

 

Applications of Triacontanol have been shown to increase both water and nutrient uptake, CO2 fixation, endogenous levels of Adenosine triphosphate (essential units of energy for all life), Rubisco Activase (often the limiting factor in C3 photosynthesis), chlorophyll a & b content and increased essential oil content of plants (not relative to trichome density).

 

Triacontanol applied to tomato plants as a foliar spray caused a significant increase in total yield and yield per plant. When triacontantol was added to the growth medium, only a temporary increase in yield and number of fruits was observed.

 

[Quote]

 

TRIA applied as a foliar spray to tomato plants increased the total yield by 12% and the number of fruits from all plants by 25% as compared to the control group. However, TRIA added to the growth medium increased total yield by only 6% and the number of fruits by 3%. 4

 

[End Quote]

 

In research conducted by D. Skogen, et al (1981) two cultivars of Chrysanthemum morifolium, ‘Golden Horim’ and ‘Golden Miquel’, were cultivated in nutrient solution containing the growth regulator triacontanol. The dry weight of the whole plant and the shoot from both cultivars increased. The number of ‘inflorescences’ (a group of flowers growing from a common stem, often in a characteristic arrangement. Also called flower cluster) per plant and the number of flowers per inflorescence also increased in response to triacontanol treatment, which in turn enhanced the quality of flowers. The number of flowers of superior quality was more than doubled.5

 

While research conducted by N. K. Srivastava et al (1989) on Opium Poppies treated with Triacontanol via foliar application demonstrated:

 

[Quote]

 

Plant height, capsule number and weight, morphine content, CO 2 exchange rate, total chlorophyll and fresh and dry weight of the shoot were significantly maximum at 0 .01 mg/1 Tria. At the highest concentration (4mg/1) total chlorophyll, CO2 exchange rate and plant height were significantly inhibited. Thebaine (a crystalline, poisonous, and anodyne alkaloid from opium) and codeine contents remained unaffected at all the concentrations. The concentration of Fe, Mn, Cu in shoots were maximum at .01 and Zn at 0 .1 mg/l Tria. Increase in shoot weight, leaf area ratio and chlorophyll content were significantly correlated with morphine content…

 

(Concluding)…

 

The present investigation reveals that Tria at concentrations upto 0 .1 mg/1 significantly enhances various processes related to production physiology

in opium poppy . The primary processes in turn contribute significantly in

increasing overall yield of straw, capsule and morphine content .6

 

[End Quote]

 

In trials conducted on essential oil bearing plants (mint) by M. Naeem et al (2011) findings showed:

 

[Quote]

 

“Out of a large number of essential oil bearing plants, mint (Mentha arvensis L.) constitutes the most important source of therapeutic agents used in the alternative systems of medicine. The mint plant has marvelous medicinal properties. In view of enhancing growth, yield and quality of this medicinally important plant, a pot experiment was conducted according to simple randomized block design. The experiment was aimed at studying the effect of four concentrations of TRIA (10-0, 10-7, 10-6 and 10-5 M) on the performance of mint with regard to growth and other physiological attributes, crop yield and quality attributes and the yield and contents of active constituents of the plant. The growth and other physiological parameters as well as yield and quality attributes were studied at 100 and 120 DAP. The foliar application of TRIA at 10-6 M concentration significantly enhanced most of the growth and other physiological attributes, crop herbage yield and the yield and content of active constituents (menthol, L-methone, isomenthone and menthyl acetate) of mint at both the stages. However, the next higher concentration of TRIA (10-5 M) exhibited slightly negative effect and did not further increase the values of the attributes studied, but it proved significantly better than the control. Application of TRIA significantly enhanced the yield and content of all the active constituents… “ 7

 

[End Quote]

 

The only known negative side effect from TRIA other than over application is that it can suppress certain defence mechanisms that help ward off insect infestation. TRIA suppresses the production of certain proteinase inhibitors that are a main defensive mechanism against insect infestation. More often than not this effect is not noticeable, but we do not suggest applying TRIA to any plants that are having issues with an insect infestation.

 

Further to this, several factors can reduce the effectiveness of TRIA as a growth stimulator. Inhibitory compounds, which have been reviewed in detail, include long chain alcohols, morpholine (commonly found in distilled water from steam condensates), and phthalate esters, particularly from polyvinyl chloride tubing.8

 

When applying Triacontanol to the plant, it’s best to apply it to the foliage (as is shown in studies). Foliar applications of TRIA consistently have better improvements in growth and allow less use than applications of TRIA to the rhizosphere. There are several TRIA product patents claiming that adding cations with a valence of  >1 (most notably calcium) improves the growth enhancing capabilities of TRIA. At least one of the mentioned patents says applications of the same cations to the rhizosphere before application had the same effect. However, to date, there has been no legitimate scientific experimentation to prove or disprove the possible TRIA/Ca synergy.

 

The best time to apply any products to the foliage of your plant is the beginning of the night cycle for your plants to allow minimum evaporation of your foliar spray. If growing indoors be sure to turn all fans off for a minimum of 6 hours, preferably until all leaves are dry. If growing outdoors try to apply spray on a night where there will be little wind. The higher the humidity the longer the spray will stay on the leaves and the better the penetration through the leaf cuticles will be.

 

References

1. M. Naeem, M. Masroor A. Khan, Moinuddin, Mohd. Idrees, Tariq Aftab (2011) Triacontanol-mediated regulation of growth and other physiological attributes, active constituents and yield of Mentha arvensis L.

2. B. Eriksen, M. K. Haugstad and S. Nilsen (1982) Yield of tomato and maize in response to foliar and root applications of triacontanol

3. Stanley Ries (1990) Triacontanol and Its Second Messenger9-b-L (+)-Adenosine as Plant Growth Substances

4. A. B. Eriksen, M. K. Haugstad and S. Nilsen (1982) Yield of tomato and maize in response to foliar and root applications of triacontanol

5. D. Skogen, A.B. Eriksen, S. Nilsen (1981) Effect of triacontanol on production and quality of flowers of Chrysanthemum morifolium Ramat

6. N .K. SRIVASTAVA** & SRIKANT SHARMA (1989) Effect of Triacontanol on photosynthesis, alkaloid content and growth in opium poppy (Papaver Somniferum L)

7. Naeem, M.; Khan, M; Moinuddin; Idrees, Mohd; Aftab, Tariq (2011) Triacontanol-mediated regulation of growth and other physiological attributes, active constituents and yield of Mentha arvensis L.

8. Ries SK (1985) Regulation of plant growth with triacontanol.

9. Stanley Ries (1990) Triacontanol and Its Second Messenger 9-b-L (+)-Adenosine as Plant Growth Substances

 

AUXINS AND CYTOKININS


Plant Hormones/Phytohormones Overview

 

Plant hormones play pivotal roles in regulating plant development, growth, and stress responses, and the interactions (‘cross-talk’) among different hormones fine-tunes various aspects of plant physiology.

 

Botanists recognize eight major groups of hormones: auxins, gibberellins, ethylene, cytokinins, abscisic acid, jasmonates, brassinosteroids and strigolactones.

 

The concept of plant hormones originates from a classical experiment on phototropism, the bending of plants toward light, carried out by Charles Darwin and his son Francis in 1880. The Darwins were able to demonstrate that when young oat plants were exposed to a lateral light source, a transported signal originating from the plant apex promoted differential cell elongation in the lower parts of the plant that resulted in it bending toward the light source. This signal was subsequently shown to be IAA, the first identified plant hormone.

 

Thimann (1948) designated the plant hormones with the name ‘phytohormones’ in order to distinguish them from animal hormones. He defined a phytohormone as “an organic compound produced naturally in higher plants, controlling growth or other physiological functions at a site remote from its place of production and active in minute amounts.”

 

A broader definition of plant hormones was proposed by Johannes van Overbeek (1950). According to Overbeek, the plant hormones are defined as “organic compounds which regulate plant physiological process— regardless of whether these compounds are naturally occurring and/or synthetic ; stimulating and/or inhibitory ; local activators or substances which act at a distance from the place where they are formed.”

 

Therefore, plant hormones are produced naturally by plants and are essential for regulating growth. They act by controlling or modifying plant growth processes, such as formation of leaves and flowers, elongation of stems, development and ripening of fruit.

 

In modern agriculture, scientists have observed the benefits of applying plant hormones to regulate growth in plants. When natural or synthetic substances are used in this manner, they are often referred to as ‘growth regulators’ or ‘plant growth regulators’. Thus, through the application of plant hormones we are able to control certain aspects of plant growth, such as reducing stretch/stem elongation, inducing earlier budset, speeding up flowering times and increasing yields.

Because phytohormones are a complex subject, for now I’ll keep things simple and just discuss two of the more important plant hormones (where hydro growers are concerned), auxins and cytokinins. I go into more detail about phytohormones here..

 

Auxins

The term auxin is derived from the Greek word “auxein” which means to grow. Compounds are generally considered auxins if they can be characterized by their ability to induce cell elongation in stems and otherwise resemble indoleacetic acid (the first auxin isolated) in physiological activity. Auxins usually affect other processes in addition to cell elongation of stem cells but this characteristic is considered critical of all auxins and thus “helps” define the hormone (Arteca, 1996; Mauseth, 1991; Raven, 1992; Salisbury and Ross, 1992). Auxins also promote adventourous root initiation and growth and are shown to increase apical dominance/stretch.

 

Auxins cause several responses in plants:

  • Bending toward a light source (phototropism)
  • Downward root growth in response to gravity (geotropism)
  • Stimulates cell elongation
  • Promotes (via ethylene production) femaleness in dioecious flowers
  • Stimulates growth of flower parts Fruit set and growth
  • Promotes formation of adventitious roots
  • Can induce fruit setting and growth in some plants

 

Cytokinins

 

Cytokinins stimulate cell division and, in contrast to auxins, are shown to reduce apical dominance (stretch), among other things.

 

Cytokinin Functions


A list of some of the known physiological effects caused by cytokinins are listed below. The response will vary depending on the type of cytokinin and plant species (Davies, 1995; Mauseth, 1991; Raven, 1992; Salisbury and Ross, 1992).

  • Stimulates cell division.
  • Stimulates morphogenesis (shoot initiation/bud formation) in tissue culture.
  • Stimulates the growth of lateral buds-release of apical dominance.
  • Stimulates leaf expansion resulting from cell enlargement.
  • May enhance stomatal opening in some species.
  • Promotes the conversion of etioplasts into chloroplasts via stimulation of chlorophyll synthesis.

 

The Role of Auxins and Cytokinins in Plant Growth

 

Auxins and cytokinins are interrelated in terms of plant growth. By artificially shifting the balance of these hormones we are able to manipulate what the plant does. In simple terms, Introduce a cytokinin containing product (higher cytokinins to auxin ratio) the result will be more foliage growth and reduced apical dominance (stretch), while the Introduction of an auxin product (higher auxin to cytokinin ratio) will result in more cell elongation, apical dominance/stretch, and adventurous root growth.

 

For now let’s talk about auxins and their use in root and growth stimulants. We’ll cover more on cytokinins shortly.

 

Auxins

 

Auxin transport is required for important growth and developmental processes in plants, including gravity response and lateral root growth. Thus, one of the key roles of auxins is that they stimulate adventourous root growth.1

 

Products such as Canna Rhizotonic, House and Garden Algen etc thus contain auxins. Additionally, auxins (e.g. IBA, IAA, NAA) are the active in most rooting compounds in which cuttings are dipped during propagation (cloning). For instance, Clonex and other rooting compounds usually contain IBA (Indole-3-butyric acid) or NAA, or a combination of both.

 

Auxin containing products are ideal for early growth (when the plant is first introduced into the system) to ensure adventurous root development. This helps the plant to settle in early and aids in mineral element uptake. Through the right balance of auxins and the right form of auxins, along with other beneficial elements (e.g. kelp, triacontanol, vitamins, and cross-linked polyacrylate polymers) a product such as Manix Roots Xtreme can greatly enhance early growth rates and reduce stress when cuttings are first placed into high intensity lighting situations.

 

Ref:

 

1) Chambers. Science and Technology Dictionary. ISBN 1-85296-10-3

 

Cytokinins

 

Cytokinins are essential for the growth of intact and isolated plant organs and tissues. Their involvement in the processes of cell division, mobilization of inorganic and organic nutrients and senescence are well documented. The high levels of cytokinins in developing seeds and fruits are indicative of a function of this type of hormone during periods of active cell division.1

 

It is shown that sex expression in plants is regulated by gibberellins which are synthesized in leaves and cause male sex expression and by cytokinins which are synthesized in the roots and cause female sex expression.2

 

When the shoots of young hemp (Cannabis sativaL.) plants were cut off the roots, cultured as cuttings, and regenerating (adventitious) roots were removed as soon as appearing, ca. 80–90% of the plants became male (had staminate flowers) whereas if the roots were allowed to develop a similar percentage became female (pistillate flowers). Treatment of de-rooted cuttings with the synthetic cytokinin 6-benzylaminopurine (15 mg/l) restored the percent of female plants to ca. 80. It is suggested that the root system plays an essential role in sex expression in hemp and that this role is related to cytokinin synthesis in the root.3

 

Cytokinins are essential for flower bud development in grapevines (Lavee 1989) and, the cytokinin concentration in phloem is critical to the induction of flowering of the long-day-plant Chenopodium murale (Nettle-leaved Goosefoot).4

 

Cytokinins are known to overcome apical dominance (stretch) by stimulating the growth of lateral and axillary buds, respectively (Faust 1989; Helgeson 1968; Leopold and Kriedemann 1975).

 

As short, squat plants, with close internodes are ideal in indoor growing situations (under lights) the use of cytokinins can prove beneficial in encouraging these traits. Further, as numerous studies have shown, the use of cytokinins stimulate cell division, resulting in higher yields.

 

The Synthetic Cytokinins – BAP, BA

 

6-Benzylaminopurine, benzyladenine or BAP is a first-generation synthetic cytokinin that elicits plant growth and development responses, setting blossoms and stimulating fruit richness by stimulating cell division.

 

Research by Paul T. Wismer et al (1995) showed that when Benzyladenine (BA), was used on apples in comparative trials against NAA, carbaryl, and daminozide, BA produced the best results of all the chemicals with increases in fruit size and weight.  It was shown that BA increased the rate of cell layer formation in the fruit cortex, indicating that BA stimulated cortical cell division. The number of cells in an apple may be increased in three ways: 1) by more rapid cell division during the cell-division phase of fruit growth, 2) by extending cell division for a longer period than normal, or 3) by some combination of these two phenomena.5

 

Research by Kevin E. Crosby et al (1981) on soybean notes,

 

[Quote]

 

“Of the five cytokinins tested at 0.1 mm concentration in 1977, BA was found to be most effective in promoting fruit-set.”

 

[End Quote]

 

In the same research it was shown that BA increased soybean yields, hypothesizing that:

 

[Quote]

 

“BA may act by increasing the ability of the treated fruits to competitively mobilize nutrients. Shortages of assimilates, particularly during the period of fruit-set, may intensify nutrient competition between developing fruits and vegetative organs. This might cause abscission of young fruits deficient in substrate or hormones. Cytokinins are known to attract nutrients to sites of application.” 6

 

[End Quote]

 

BA to Reduce Apical Dominance (Stretch)

 

Apical dominance (stretch) is caused by the apical bud (top shoot of the plant) producing IAA (auxin) in abundance. Thus, a primary factor in the mechanism of apical dominance is a hormonal interaction between auxins and cytokinins. In simple terms apical dominance is antagonized by BA (cytokinin) which interferes with the abundance of IAA by increasing the naturally occurring cytokinin to auxin ratio. 7

 

In research conducted by Nii et al (1986) 6-benzylamino purine (BA), was used as a foliar spray in orchard and potted plants to study its effect on branching and leaf development in peach trees, and to analyze the factors influencing its effectiveness, it was shown:

 

1) During the expansion of cells in peach leaves sprayed with BA, the number of chloroplasts per cell and the amount of chloroplast DNA increased with the cell size, after this phase the chloroplast number per cell continued to increase, and 2) BA-treated trees were more compact than non BA treated trees and many branches of BA-treated shoots contributed to a less open growth habit.8

 

Similarly, in research conducted by Samanthi P. Herath et al (2004) on Hibiscus cannabinus L (Kenaf) it was shown that in BA treated plants supernumerary vegetative shoot buds were observed in and near the axillary buds. In the control plants (non BA treated plants) neither axillary nor adventitious buds developed. The results suggested that the treatment with BA reprogrammed the developmental fate of a large number of cells in the shoot apex of kenaf. Further, it reconfirmed the ability of BA to overcome the apical dominance of shoots.9

 

Conclusion and Discussion

 

The correct useage of auxins and cytokinins used at varying ratios and times during the grow and flowering cycles can greatly stimulate desirable effects in plants. Auxins used in early grow, promote adventurous rooting, help relieve plant stress, and promote plant health/vigour.

 

Cytokinins, used during early bloom, can greatly aid in setting up a better plant structure (short squat plants with close internodes), and used thereafter can stimulate cell division (growth rates) and as a result increase yields.

 

Which brings us to our next point. Kelps as biostimulants – or as the case may be, more on auxins and cytokinins and other…. (next page)

 

References:

 

  1. KEVIN E. CROSBY, LouIs H. AUNG, AND GLENN R. Buss (1981) Influence of 6-Benzylaminopurine on Fruit-Set and Seed Development in Two Soybean, Glycine max (L.) Merr. Genotypes’
  2. M. Kh. Chailakhyan (1979) Genetic and Hormonal Regulation of Growth, Flowering, and Sex Expression In Plants
  3. M. Kh. Chailakhyan and V. N. Khryanin (1978) The role of roots in sex expression in hemp plants
  4. T. Bubán (2000) The use of benzyladenine in orchard fruit growing: a mini review.
  5. Paul T. Wismer and J.T.A. Proctor (1995) Benzyladenine Affects Cell Division and Cell Size during Apple Fruit Thinning
  6. KEVIN E. CROSBY, LouIs H. AUNG, AND GLENN R. Buss (1980) Influence of 6 enzylaminopurine on Fruit-Set and Seed Development in Two Soybean, Glycine max (L.) Merr. Genotypes’
  7. Gary J. Keever and Thomas J. Brass Presence of Offsets Reduces Hosta’s Response to Benzyladenine http://www.ag.auburn.edu/hort/landscape/gary7.html
  8. N. Nii, T. Kuroiwa (1986) Morphological and anatomical development of peach shoot and leaves as influenced by 6-benzylamino purine
  9. Samanthi P. Herath, Takayuki Suzuki and Kazumi Hattori (2004) Light and Scanning Electron Microscopic Analysis of Benzyl Adenine Induced Multiple Shoot Regeneration in Kenaf (Hibiscus cannabinus L.)