Chlorophyll formation

Copper is an essential micronutrient required in the growth of both plants and animals. In humans, it helps in the production of blood haemoglobin. In plants, copper is an important component of proteins found in the enzymes that regulate the rate of many biochemical reactions in plants. Plants would not grow without the presence of these specific enzymes. Research projects show that copper promotes seed production and formation, plays an essential role in chlorophyll formation and is essential for proper enzyme activity, disease resistance and regulation of water in plants (Rehm and Schmitt, 2002). 

Interferes with chlorophyll formation in plants by inhibiting the conversion of coproporphyrinogen to proporphyrinogen by competing with iron... 

Effect of Thallium on Plants and Animals. On January 29, 1863, R. C. Bottger announced that he had detected spectroscopic traces of thallium in wine, chicory, tobacco, sugar beet, and beech wood, and had concluded that it must be widely diffused in the vegetable kingdom (47, 73). Because of the toxicity of thallium compounds, they are sometimes added in small concentrations to the soil of rodent-infested fields. Too high a concentration of thallium inhibits germination, growth rate, and chlorophyll formation in the crops, especially in rainy weather (78). 

According to Table VI, the quantum yield of allylthiourea oxygenation, 4ao2, exceeds the quantum yield of triplet chlorophyll formation,... 

Kinetic Expression of Growth and Chlorophyll Formation of Hairy Roots... 

Inhibits cell elongation. Also influences developmental cycle, leading to increased flowering and harvest. May also increase chlorophyll formation and root development Animals. 97% is eliminated within 24 hr, principally unchanged Plants. Converted to choline chloride Soil. Rapidly degraded by microbial activity. DTJ0 in 4 soils averaged 32 days at 10°C 1-28 days at 22°C. Low to medium mobility... 

Physiol 48, 316 (1971). Use of labelled acid in porphyrin biosynthesis studies C. A. Rebciz et al. ibid. 46. 543 (1970). Enhancement of chlorophyll formation S. Ochiai, E. Hase, Plant Cell Physiol 11, 663 (1970), Proposed use as photodynamic herbicide C. A. Rebei2 et al. Enzyme Mt eroh. 

However, wheat protoplasts have no other demonstrable responses to cytokinin and, therefore, the lack of a cytokinin effect on calcium transport is not a decisive test. Zhao and Ross [69] used zeatin induced growth and chlorophyll formation in excised cucumber cotyledons as cytokinin responses to examine the effects of calcium chelators, ionophore and several anti-calmodulin drugs. None of these drugs affected the two cytokinin responses unless used at concentrations high enough to cause indirect damage. 

Besides the bleaching cause by either carotene inhibition or peroxidation more targets for "bleaching herbicides" are conceivable, e.g., interference with chlorophyll formation itself. DTP, a substituted pyrazole, was reported to induce chlorosis by blocking... 

Although phenylalanine alone was able to alleviate glyphosate inhibition of anthocyanin formation, feeding tyrosine in addition to phenylalanine was required to achieve partial alleviation of the inhibition of chlorophyll formation. Additional tryptophan did not further increase the chlorophyll content of cotyledons. Further work with buckwheat indicated that a 24-h light or dark incubation of untreated excised hypocotyls had little effect on endogenous shikimate content... 

Some plants, such as spinach and tobacco, will absorb even larger amounts of potassium than of nitrogen when the avadable supply is large. The exact role of potassium has not been determined with certainty but the evidence indicates that it functions in a variety of ways (Evans and Sorger, 1966). Hewitt (1951) expressed the opinion that it helps to maintain cell organization, hydration and permeability and hence directly or indirectly influences many enzyme systems. It may also help to maintain available supplies of iron, which is so essential in chlorophyll formation and functioning. Where potassium is deflcient it has often been noted that carbohydrates tend to accumulate in plants, presumably because of a disruption of the synthetic metabolism, but a causal relationship has not been established. In cell metabolism there are such close interrelations between potassium, calcium and magnesium that it is difficult to establish the individual roles of each of these elements. 

Bleaching may be a result of photooxidative events generated within the plant cell or chloroplast, leading to the destruction of the plant pigments or direct inhibition of pigment biosynthesis, whereby carotenoid and chlorophyll formation is prevented [5]. 

INTERMEDIATES, CATALYTIC COMPONENTS AND LIGHT AND DARK REGULATION OF ALA AND CHLOROPHYLL FORMATION IN THE GREEN ALGA SCENEDESMUS... 

Virgin, H.I., Action spectrum for the elimination of the lag phase in chlorophyll formation in previously dark grown leaves of wheat. Physiol. Plant., 14, 439, 1961. 

PRAT S, I960. (Th6 effect of humus substances on the uptake of mineral salts and on the chlorophyll formation in plants. Acta agrobotanica, 9, 117-121. 

In the green plant, iron appears as a constituent of the chloro-plasts. It is not part of the chlorophyll molecule, but is necessary for chlorophyll formation. When iron is withheld from plants, local chlorosis develops, and can be cured by application of iron salts to the soil. 

A Factor in Plant Growth.— The response of plants to iron depends both on the nature of the salt supplied and the nature of the soil. A slight deficiency of iron can diminish greatly the yield of a crop without causing much change in appearance an acute deficiency alters the colour of the leaves owing to defective chlorophyll formation. 

Glyphosate is phloem mobile and accumulates in accordance with source-sink relationships in meristematic areas of the treated plants. " The general physiological effects of glyphosate are consistent with its acting as a metabolic poison. Death is a slow process, requiring days or weeks much more rapid effects, within hours, can be demonstrated at the biochemical level. These effects can be explained if the turnover rates of specific proteins, and therefore sensitivity to amino acid synthesis inhibition, differ. Inhibition of phenolic biosynthesis and chlorophyll formation and effects on the levels of the phytohormone 3-indoleacetic acid have been considered as target sites but can be viewed as necessary consequences of the primary interference with aromatic amino acid biosynthesis. " ... 

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