Abstract
Recent reports have emphasized that foliar applications of stimulatory concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) induce greater growth and productivity of several crop plants. This stimulatory action of the hormone has been found to be augmented by simultaneous application of such micronutrients as iron, manganese, zinc, copper, and boron (Wort, 1964). However, no systematic attempt has so far been made to investigate physiological and biochemical changes induced in a relatively short period following these treatments. A correlation of such changes with final improvements in growth and yield may provide a better understanding of the mechanism of action of the hormone. In addition, the biochemical nature of the augmentory role played by micronutrients on 2,4-D action is yet undefined. It was therefore felt desirable to investigate these aspects. Bean plants (Phaseolus vulgaris L. Var. Top Crop) were grown in plastic cans under controlled environment in a growth room. When the plants were 2 weeks old, the following treatments were applied as foliar sprays: (1) 2,4-D (1 ppm), (2) micronutrient solution (Fe, Mn, Zn, Cu, B; 5x10⁻⁴ M) and (3) 2,4-D-mineral solution, with the same components as (2) plus 1 ppm 2,4-D. Measurements of juvenile growth, chemical composition of the plants, respiration and photosynthetic rates and activities of some of the key enzymes of carbohydrate and nitrogen metabolism were made 5, 10, and 15 days after the treatment, to determine the course and basis of stimulation. Yield of pods and seeds and the vitamin C content of pods were also determined. The results revealed that: (1) maximum stimulation resulted from the use of hormone-mineral spray, (2) treatments involving 2,4-D resulted in progressive increase in plant height, leaf number, and leaf area; fresh and dry weights of root, stem and leaves; chlorophyll content and total sugar in leaves, (3) sucrose and reducing sugars were lower in stems and roots of treated plants; (4) moisture content was not affected significantly by any treatment; (5) quantitative chromatographic determination of the free, ethanol-soluble amino acids revealed a reduction in amino acid content in 2,4-D-treated plants, particularly in leaves, and an increase in plants to which micro-nutrient spray had been applied. The amino acid content of plants treated with 2,4-D plus minerals was intermediate between those resulting from the other two treatments; (6) measurement made with intact plants using an infrared CO2 analyzer revealed increases in rates of respiration and photosynthesis of the aerial portions 10 and 15 days after treatment; (7) significant increases in the activity of phosphorylase, phosphoglyceryl kinase, succinic dehydrogenase, catalase, nitrate reductase, and transaminase in all organs were also apparent at 10 and 15 days after treatments involving 2,4-D; (8) treatments involving 2,4-D also resulted in significant increases (P=0.05) in number and fresh weight of green pods, in seed number, and in total seed weight. Weight of the individual seed was not significantly altered; (9) the green pods from treated plants had higher vitamin C content at harvest time, but the moisture content was not altered by treatment. The green pods of plants which had received 2,4-D alone or 2,4-D plus minerals lost less ascorbic acid and moisture during 4 days storage at room temperature. The stimulation of enzyme activities is explained on the basis of hypothesis proposed by Wort (1964) that 2,4-D may participate in the formation of substrate-enzyme-regulator complex. Minerals may affect the activity of formation of this complex. In proposing a physiological and biochemical basis for the stimulation in growth and yield under 2,4-D action, the following points are emphasized: (1) the stimulated rate of photosynthesis produced a larger amount of photosynthate which could be utilized in the biosynthesis of all cell constituents or serve as substrate for respiration; (2) the stimulated rate of respiration and activity of such enzymes as phosphoglyceryl kinase and succinic dehydrogenase resulted in an increased supply of available energy, as ATP and reduced nucleotides, for biosynthesis, and in larger amounts of keto acids which provide the carbon skeletons of amino acids; (3) the greater activity of nitrate reductase and transaminase resulted in an augmented supply of amino acids responsible for the enhanced synthesis of protein evident in greater growth and productivity.
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Claims 20
Claim · model-written summary
Hormone-mineral spray produced maximum stimulation.
- Taxon
- bean (Phaseolus vulgaris L.)
Phaseolus vulgarist0 - Treatment
- hormone-mineral spraye0
- Outcome
- maximum stimulatione0
- Direction
- maximume0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maximum stimulation resulted from the use of hormone-mineral spray”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D treatments progressively increased plant height, leaf number and leaf area.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-De0
- Outcome
- plant height, leaf number, and leaf areae0
- Direction
- progressive increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“treatments involving 2,4-D resulted in progressive increase in plant height, leaf number, and leaf area”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D treatments increased fresh and dry weights of roots, stems and leaves.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-Dt1
- Outcome
- fresh and dry weights of root, stem and leavese0
- Direction
- increaseinferrede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fresh and dry weights of root, stem and leaves”
t0“bean (Phaseolus vulgaris L.)”
t1“2, 4-D-mineral”
Claim · model-written summary
2,4-D treatments increased leaf chlorophyll and total sugar.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-Dt1
- Outcome
- chlorophyll content and total sugar in leavese0
- Direction
- increaseinferrede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“chlorophyll content and total sugar in leaves”
t0“bean (Phaseolus vulgaris L.)”
t1“2, 4-D-mineral”
Claim · model-written summary
Treated plants had lower sucrose and reducing sugars in stems and roots.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- treated plantse0
- Outcome
- sucrose and reducing sugarse0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sucrose and reducing sugars were lower in stems and roots of treated plants”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
No treatment significantly affected moisture content.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- any treatmente0
- Outcome
- moisture contente0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“moisture content was not affected significantly by any treatment”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D reduced free amino acid content, especially in leaves.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-D-treatede0
- Outcome
- amino acid contente0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a reduction in amino acid content in 2,4-D-treated plants, particularly in leaves”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
Micronutrient spray increased free amino acid content.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- micro-nutrient spraye0
- Outcome
- amino acid contente1
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an increase in plants to which micro-nutrient spray had been applied”
t0“bean (Phaseolus vulgaris L.)”
t1“2, 4-D-mineral”
e1“a reduction in amino acid content in 2,4-D-treated plants, particularly in leaves”
Claim · model-written summary
Amino acid content after 2,4-D plus minerals was intermediate between other treatments.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-D plus mineralse0
- Outcome
- amino acid contente0
- Direction
- intermediatee0
- Comparator
- other two treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amino acid content of plants treated with 2,4-D plus minerals was intermediate between those resulting from the other two treatments”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
Respiration and photosynthesis increased 10 and 15 days after treatment.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- treatmente0
- Outcome
- rates of respiration and photosynthesise0
- Direction
- increasese0
- Qualifier
- 10 and 15 days after treatmente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases in rates of respiration and photosynthesis of the aerial portions 10 and 15 days after treatment”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D treatments increased activities of phosphorylase, phosphoglyceryl kinase and succinic dehydrogenase.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-De0
- Outcome
- activity of phosphorylase, phosphoglyceryl kinase, succinic dehydrogenasee0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increases in the activity of phosphorylase, phosphoglyceryl kinase, succinic dehydrogenase, catalase, nitrate reductase, and transaminase in all organs were also apparent at 10 and 15 days after treatments involving 2,4-D”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D treatments increased activities of catalase, nitrate reductase and transaminase.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-De0
- Outcome
- catalase, nitrate reductase, and transaminasee0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increases in the activity of phosphorylase, phosphoglyceryl kinase, succinic dehydrogenase, catalase, nitrate reductase, and transaminase in all organs were also apparent at 10 and 15 days after treatments involving 2,4-D”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D increased green pod number and fresh weight.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-De0
- Outcome
- number and fresh weight of green podse0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“treatments involving 2,4-D also resulted in significant increases (P=0.05) in number and fresh weight of green pods”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D increased seed number and total seed weight.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-Dt1
- Outcome
- seed number, and in total seed weighte0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increases (P=0.05) in number and fresh weight of green pods, in seed number, and in total seed weight”
t0“bean (Phaseolus vulgaris L.)”
t1“2, 4-D-mineral”
Claim · model-written summary
Individual seed weight was not significantly altered.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-Dt1
- Outcome
- Weight of the individual seede0
- Direction
- not significantly alterede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Weight of the individual seed was not significantly altered”
t0“bean (Phaseolus vulgaris L.)”
t1“2, 4-D-mineral”
Claim · model-written summary
Green pods from treated plants had higher vitamin C content at harvest.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- treated plantse0
- Outcome
- vitamin C contente0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the green pods from treated plants had higher vitamin C content at harvest time”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
Pod moisture content was not altered by treatment.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- treatmente0
- Outcome
- moisture contente0
- Direction
- not alterede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the moisture content was not altered by treatment”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D alone reduced ascorbic acid and moisture loss during storage.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-D alonee0
- Outcome
- ascorbic acid and moisturee0
- Direction
- lost lesse0
- Qualifier
- 4 days storage at room temperaturee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plants which had received 2,4-D alone or 2,4-D plus minerals lost less ascorbic acid and moisture during 4 days storage at room temperature”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
2,4-D plus minerals reduced ascorbic acid and moisture loss during storage.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Treatment
- 2,4-D plus mineralse0
- Outcome
- ascorbic acid and moisturee0
- Direction
- lost lesse0
- Qualifier
- 4 days storage at room temperaturee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plants which had received 2,4-D alone or 2,4-D plus minerals lost less ascorbic acid and moisture during 4 days storage at room temperature”
t0“bean (Phaseolus vulgaris L.)”
Claim · model-written summary
The authors propose that increased photosynthesis, respiration and enzyme activity support growth and yield.
- Taxon
- bean (Phaseolus vulgaris L.)Phaseolus vulgarist0
- Outcome
- larger amount of photosynthatee0
- Qualifier
- stimulated rate of photosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the stimulated rate of photosynthesis produced a larger amount of photosynthate which could be utilized in the biosynthesis of all cell constituents or serve as substrate for respiration”
t0“bean (Phaseolus vulgaris L.)”
The same questions in other papers
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See all 24 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.