Chlorophyll Decomposition Research Articles

Effects of silicon application on drought resistance of cucumber plants

A study on the effects of silicon supply on the resistance to drought in cucumber plants was conducted in pot experiments. The results suggested that in the absence of stress, silicon slightly enhanced the net photosynthetic rate, but significantly decreased the transpiration rate and stomatal conductance in cucumber plants. Silicon enhanced the net photosynthetic rate of cucumber plants under drought stress. Since silicon decreased the stomatal conductance, enhanced the capacity of holding water, and kept the transpiration rate at a relatively steady rate during drought stress, the photosynthesis of the cucumber plants was sustained. And under drought stress, silicon increased the biomass and water content of leaves in cucumber plants. Silicon decreased the decomposition of chlorophyll in cucumber plants under drought stress, limited the increase of the plasma membrane permeability and malondialdehyde (MDA) content in leaves, alleviated the physiological response of peroxidase (POD) to drought stress, maintained the superoxide dismutase (SOD) normal adaptation, and increased the activity of catalase (CAT). Under severe stress, these physiological biochemical reactions showed positive correlations with the amount of silicon supply. These findings demonstrated that silicon enhanced the resistance of the cucumber plants to drought. Statistical analysis indicated that under drought stress the cumulative value of biomass showed a highly significant correlation with the cumulative value of diurnal photosynthesis (r = 0.9812, p < 0.01), and was significantly correlated with the water content of leaves (r = 0.8650, p < 0.05). These results demonstrated that under drought stress the first factor responsible for the effects of silicon application on the cumulative value of biomass was the increase of photosynthesis, and the second factor was the enhancement of the water holding capacity. Based on these facts, it was concluded that silicon enhanced the resistance to drought mainly by taking part in the metabolism of plants.

Physiological changes in the antioxidant system of broccoli flower buds senescing during short-term storage, related to temperature and packaging

The superoxide dismutase (SOD) and the antiradical activity (RSA) together with the phenylopropanoids, flavonoids and chlorophyll levels in flower bud tissue were estimated during short-term storage of broccoli Lord cultivar. Catalase (CAT) and peroxidase (POD) activities were detected in broccoli flower branchlets. The activity of SOD increased gradually at both storage temperatures (20 and 5 °C), while the RSA increased only in higher temperature. Increase in catalase activity was observed after 1-day storage of non-packaged broccoli at 20 °C, followed by its decrease, and after 1- and 3-day storage of the packaged heads. In the case of low temperature the enzyme activity increased only after 10 days of storage. Storage of broccoli at room temperature caused the significant increase of peroxidase activity, while at low temperature (5 °C) activity of the enzyme rose after 10 days. During the storage, the accumulation of phenylopropanoids and flavonoids in broccoli flower buds was observed. The rapid decrease of chlorophyll was observed only in the case of broccoli heads stored at 20 °C. Applying of polyethylene foil to packaging of broccoli heads during storage in most cases decreased the SOD, CAT, POD antiradical activities and phenol content, and slowed down chlorophyll decomposition in flower buds. The obtained results emphasize the active role of antioxidant components of broccoli flower buds senescing during short-term storage, especially in intense stress conditions.

Pigment Changes in Fried Dough Containing Spinach Powder During Storage in the Dark

ABSTRACT: Changes in chlorophyll and carotenoid contents of fried dough supplemented with spinach (Spinacia oleracea) powder were investigated during storage. Flour dough containing spinach powder was fried in soybean oil at 160 °C for 1 min and stored in a glass bottle at 60 °C incubator in the dark up to 12 d. Chlorophyll contents decreased with storage time, whereas pheophytin contents increased followed by decrease. Decomposition of chlorophyll a was faster than that of chlorophyll b. Carotenoids were decomposed during storage; however, the decomposition rate was lower than that of chlorophylls. Decrease in carotene contents with storage time was slower than that in xanthophylls.

Thermal decomposition of adsorbed β-carotene and chlorophyll on acid-activated clay

β-Carotene and chlorophyll have been adsorbed from solution in benzene and hexane onto acid-activated clay. Five steps were observed during the thermal decomposition of β-carotene and chlorophyll on acid-activated clays. The adsorbed solvents desorbed during the first step and the adsorbed materials decomposed during the dehydroxylation of the clay. The activation energies of all the steps have been determined.

Effects of Light on Decomposition of Chlorophyll in Green Leaves

Effects of Light on Decomposition of Chlorophyll in Green Leaves

Deterioration of Fats and Oils and Its Preventive Countermeasures

A review on 119 original papers for the Japan Oil Chemist's Society Award is presented.1) After heating the decrease of the oxidative stability by tocopherol (Toc) degradation was larger for olive, coconut and hardened oils than for soybean, corn, cottonseed, and rapeseed oils. Decomposition of Toc in oils was apparently promoted by the oxidative products (especially oxidized fatty acids: fatty substances insoluble in petroleum ether) and free fatty acids. The preventive effects of additive on the thermal decomposition of Toc in oils were in the order of gallic and thiodipropionic acids>cystine>homogentisic acid>tryptophan>soya lecithin>catechins.2) Histidine (His) and Cu (II)-His complex inhibited the photosensitized of unsaturated fatty acid by quenching 1O2, and O2-, respectively. Gly-Gly-His inhibited both the outoxidation and the photosensitized oxidation in the presence of copper (II) ion.3) Antioxidative activity of metabolic products of several amino acids was investigated. In the metabolites of tryptophan, proline, and phenylalanine, the 3-hydroxyanthranilic acid, 5-hydroxyproline and homogentisic acid showed great antioxidative activity on the autoxidation of lard, respectively.4) The greatest anitioxidative activity was recognized with methanol extracted fraction of the smoke or tea and tea-grounds, and by the analysis, naphtol, isoamyl gallate and hydroquinone were detected in smoke. Epigallocatechin in tea showed the strongest antioxidative effect for oils.5) Antioxidant was adsorbed on paper, and the antioxidant paper was packed with various foods in bag. Oxidative stability of Foods was considerably improved with indirect method of antioxidant NDGA and BHA.6) BHA, NDGA, isoamyl gallate and hydroquinone showed a potent antiseptic and antimold action on the microbe or mold.7) The decomposition of amino acids, vitamins, and chlorophyll was apparently promoted by oxidative products (oxidized fatty acids, peroxide and malonaldehyde etc.) of oil.8) The rats fed oxidized oil showed growth depression, whereas better growth was observed those fed same oil with Toc, oryzanol, pyridoxine, and water extractum of animal liver or garlic, respectively.

Chlorophyll decomposition in Skeletonema costatum: a problem in chlorophyll determination of water samples

Chlorophyll decomposition in Skeletonema costatum: a problem in chlorophyll determination of water samples

Time-resolved laser desorption. III. The metastable decomposition of chlorophyll- a and some derivatives

Chlorophyll- a is ionized by laser desorption in a field-free, grounded ion source of a time-of-flight mass spectrometer. The use of a time delay between the ionizing laser pulse and the ion drawout pulse permits metastable decompositions to occur prior to mass analysis. The fragmentation pattern observed in the resultant mass spectra varies with the magnitude of the time delay and is consistent with multistep fragmentation processes for which the rate constants are of the order of 10 5–10 6 s −1. Two derivatives are also examined, for which metastable decomposition is not observed.

Kinetics of Chlorophyll Degradation to Pyropheophytin in Vegetables

ABSTRACTPyropheophytins a and b were determined as predominant chlorophyll derivatives in heat processed spinach. Chlorophylls a, b, pheophytins a, b and pyropheophytins a, b were quantitated in fresh, blanched and heat processed spinach at 116, 121 and 126°C. First order degradation rate constants were determined to calculate activation energies of 25.2 and 22.5 Kcal/mole for chlorophylls a and b and 20.7 and 15.7 Kcal/mole for pheophytins a and b, respectively. Based on the results, the suggested mechanism for the decomposition of chlorophyll during heat processing of vegetables is: Chlorophyll Pheophytin Pyropheophytin. Pyropheophytins a and b were major chlorophyll degradation products found in all commercially canned vegetable products surveyed.

Source and sink development during kernel filling of two spring wheats as affected by root size and cytokinin applications

AbstractThe effects of partial root removal and cytokinin applications at different times during kernel filling were examined at two contrasting wheat genotypes grown in controlled environmental conditions. Treatments affected the development of leaves, and grain setting, but hardly grain growth; the influence strongly depended on time, but not on genotype. Cutting off roots „early”︁ after heading caused immediate damage, especially in the lower leaves. Later on, chlorophyll decomposition and loss of green area was accelerated. „Early”︁ cytokinin applications were not able to prevent these effects. If root size was reduced at a „medium late”︁ or „late”︁ stage no spontaneous effects were observed, but leaf senescence was more drastic, the later the treatments were carried out. Enhancement of senescence due to root removal, could generally be inhibited by (medium) „late”︁ cytokinin applications. As to grain setting, „early”︁ cytokinin applications could not counteract the reduction induced by „early”︁ root removal. In most of the trials there was no evidence that root removal or cytokinin applications affected grain growth. Some secondary effects of the treatments on root growth are discussed with regard to the importance of root system as a site of cytokinin synthesis during grain filling.

Wirkung einiger Cytokinin-analoge Derivate des N-alkyl-N′-phenylharnstoffs auf die Verzögerung des Chlorophyllabbaus und auf die Nitratreduktase-Aktivität in jungen Blättern von Hordeum vulgare

Summary The present paper describes the influence of a homologous series of phenylthiourea on some senescence phenomena in barley leaves. In particular the inhibition of chlorophyll decomposition and induction of the nitrate reductase activity were considered. The following relations between the activity of the agents and their structure have been found: 1. The activity of the tested derivatives depends on the type of the substituent and its position at the phenyl thiourea ring. 2. In isomeric compounds the most effective position of a substituent in the phenylthiourea ring depends on its chemical properties. 3. The para-isomers show the highest physiological activity. 4. With meta-isomers a linear correlation can be determined using the values of the Hammet’s constant.

Pigment cycle in a north German lake

SummaryThe vertical distribution of photosynthetic pigments and their degradation products in a north German lake was studied fluorometrically over a period of one year. The maximum chlorophyll concentration was usually in the euphotic zone and at times coincided with that of the phaeo-pigments. Phaeo-pigments maximum was usually in the thermocline, near the base of the euphotic zone. The phaeo-pigments maximum occurred above the portion of the water column where nutrients increased in concentration. Investigations at greater depths revealed that there was a percentage increase in the degradation of chlorophyll with depth. The seasonal cycle of chlorophyll and their degradation products showed a bimodal pattern. Chlorophyll degradation products in the Pluss See constitute a significant fraction of the chlorophylls. From these observations it is concluded that post-lytic photochemical oxidation could be responsible to a large extent for chlorophyll decomposition products in situ in lakes. Chlorophyll derivatives, especially phaeophytins and phaeophorbides, have been detected chromatographically in Pluss See and Gerbiener See.

Isolierung einer Endopeptidase aus alternden Tabakblättern und ihre Beziehung zum Vergilben

An endopeptidase which hydrolyzes polypeptides between hydrophobic amino acid residues was isolated from yellowing leaves of Nicotiana tabacum. The enzyme has a molecular weight of 9000 to 10 000 and a maximum activity at pH 5.0 and 40° C. Half-saturation of the enzyme was reached with lamellar system as substrate at 10 −1 g per liter. For comparison the Michaelis constant for myoglobin was determined in the same system and found to be 2 × 10 − 5 moles per liter. Enzyme preparations made in the same way from green leaves were either inactive or slightly active. With rabbit antiserum to the endopeptidase the enzyme preparation gave one precipitation line in the Ouchterlony test, although in some cases one or two weak secondary lines were observed. Protein extracts from green leaves also gave one precipitation line. In Polyacrylamide gel electrophoresis only one band was obtained; enzymatic activity could be found only in the region of this band. The enzyme hydrolyzes up to 30 % of the protein of the lamellar system. Treatment of the lamellar system with the endopeptidase accelerates the decomposition of chlorophyll by photo-oxidation.

Relation between the level of endogenous growth regulators and the differentiation of the fungusLentinus tigrinus studied in a synthetic medium

The fungusLentinus tigrinus was cultivated in a synthetic medium. During vegetative growth of mycelium and differentiation of fruiting bodies samples serving for determination of endogenous growth regulators were collected. The material was extracted with methanol, separated by chromatography and the isolated fractions were tested. Substances of auxin type were assayed with coleoptile segments of oat plants, gibberellins by measuring the hypocotyl growth in the lettuce and cytokinins from the degree of chlorophyll decomposition in the leaf segments of barley. Very low content of auxins was found in all phases of growth and differentiation of the fungus. The content of gibberellin substances was relatively high during the whole life of the fungus. The highest content is found in the vegetative mycelium and in the differentiated fruiting body, especially in the cap; it decreases during the differentiation of fruiting bodies. The content of cytokinins is equally high and the pattern of its change resembles that of the gibberellins. Its maximum is reached in young vegetative mycelium, it decreases when fruiting bodies are formed and when they are growing. Minimum is reached in the differentiated stalk, where also the amount of inhibitions is the highest. Experimental results show that during differentiation of fruiting bodies and their morphogenesis not only gibberellins and cytokinins are of importance, but also substances of an inhibitory character. A relatively high amounts of these substances was secreted into the cultivation medium. In a synthetic nutrient solution they may be easily demonstrated.

Studies on the coloring of Satsuma mandarin (Citrus unshiu MARC.)

1. The fruit was enclosed in jars with rubber lids through which the ethylene was injected with a syringe. When the jar was left covered there was no change in the rind color. One day after treatment the lid was removed, exposing the fruit to the air. This caused the fruit to degreen rapidly.2. Opening the lid 12-18 hours after the treatment resulted in the greatest chlorophyll decomposition.3. 500-1, 000ppm of ethylene was the most effective concentration.4. 15-25°C was the suitable temperature of treatment. Also, it was found that the temperature after opening the lid was important for degreening.5. Determining the ethylene concentration in fruits and jars, it was found that ethylene was absorbed rapidly through the rind and the ethylene concentration inside and outside of the rind became almost the same in 150 min. after the injection. After opening the lid, however, it seemed that most of the ethylene was released rapidly from the fruits.

Effects of 6N‐Benzyladenine on Primary Leaves of Intact Bean Plants and on their Sodium Absorption Capacity

AbstractThe application of 6N‐benzyladenine (BA) to primary bean‐leaves attached to the intact plant resulted in increased leaf area. This was due to an extension of the duration of the period of leaf expansion.The dry‐weight percentage of untreated leaves decreased continuously from emergence to abscission. In BA treated leaves this decrease stopped with the cessation of leaf expansion. Net chlorophyll synthesis occurs in untreated leaves as long as they continue to expand, shortly afterwards net chlorophyll decomposition starts. Benzyladenine treatments diminished the rate of chlorophyll synthesis immediately after its first application, but prevented the loss of chlorophyll afterwards. The abscission of primary leaves was also delayed by BA.During the period of rapid leaf expansion in slices cut from BA treated leaves, sodium absorption rates were lower than in those from untreated leaves. From the age of 14 days after sowing, till abscission time of untreated primary leaves, the BA treatment did not significantly affect sodium absorption rates by leaf slices.

The role of chlorophyllase and light in the decomposition of chlorophyll from marine phytoplankton

In a study of the biochemical aspects of the decomposition of chlorophyll, measurement of the activity of the enzyme chlorophyllase in marine phytoplankton was attempted in vitro by observing the conversion of chlorophyll to chlorophyllide. Our experiments indicate that in darkness and at room temperatures any enzymatic activity, if present, is immeasurable by the techniques employed. As a consequence, we have considered the photo-bleaching of chlorophyll as a possible means of decomposition. This has been identified as a photo-oxidation and the decomposition of the pigment is extremely rapid. Our experiments show that a similar photo-oxidation exists in fractured cells and degraded pigments found in the feces of marine herbivores. Although the rate of photo-bleaching is slower in vivo than in vitro, we postulate that this is a principle mechanism for pigment decomposition.

Effects of Light and Attached Organs on the Chlorophyll Decomposition in Rice Leaf Blade

Effects of Light and Attached Organs on the Chlorophyll Decomposition in Rice Leaf Blade

Einfluβ von Cytokininen und anderen Wuchsstoffenauf die Stoffverlagerung in abgeschnittenen Blättern

Summary Influence of cytokinins and other growth substances on translocation of some plant compounds in detached leaves An investigation was carried out to study the influence of cytokinins and some growth substances on senescence and translocation processes in detached leaves of Tropaeolum majus L. (and tobacco). The leaves were stored under humid conditions in the dark Kinetin, benzyladenine (BA), zeatin and gibberellic acid (GA3) (10 — 30 mg/l) applied on the whole leaf-blade (leaves without petiole) delayed the decomposition of chlorophyll and protein to about the same extent. The decomposition of carbohydrates was unaffected. Application of kinetin to one half of cut leaf-blades caused a translocation of carbohydrates, N- and P-compounds, and K-ions (or of Rb after treatment with labelled Rb) from the untreated to the treated leaf part. Ca and Na were not translocated. In some cases soluble N was accumulated on the place of treatment in spite of a netto-decomposition of protein. BA and zeatin were almost as effective as kinetin. It seems that cytokinins affect by „retention” or “attraction” all those mineral elements, from which a good mobility for retranslocation is known. GA had no effect on the translocation of the compounds mentioned, probably because of their migration to the untreated area also In cut leaves with petioles carbohydrates, N- and P-compounds and K-ions moved from the blades to the petioles. Following this a new synthesis of protein and carbohydrates in the petiole occured. Treatment of the leaf blade with cytokinins and GA diminished this translocation considerably. IAA however increased the downward stream. It is assumed that the absorbed IAA migrated downward into the petiole in the same way as auxin normally does in cut leaves, and therefore the accumulation in the petiole (“sink”) was increased. Uptake of GA and zeatin via the cut petiole delayed senescence as application on the leaf blade did, that is, over the whole leaf blade. In the case of kinetin and BA, however, the leaves remained green only in the area near the connection of leaf and petiole. This shows that the growth substances spread out in the leaf blade to a different extent The results obtained with kinetin on leaves from Tropaeolum were confirmed not only by detached leaves of tobacco but also by tobacco leaves still attached on plants.

PHOTOSYNTHETIC PIGMENTS OF SYMBIOTIC DINOFLAGELLATES (ZOOXANTHELLAE) FROM CORALS AND CLAMS

1. The photosynthetic pigments of the brown symbiotic algae (zooxanthellae) isolated from five tridacnid clams and nine corals were found to be identical with the pigments of the dinoflagellate Amphidinium. Identifications were carried out by two-dimensional paper chromatography and by absorption spectrophotometry. Both zooxanthellae and dinoflagellates contained cholorphylls a and c, β-carotene, peridinin, neo-peridinin, dinoxanthin, neo-dinoxanthin, diadinoxanthin, and three minor xanthophyll fractions not previously described.2. Peridinin, crystallized from Tridacna gigas, or isolated by paper chromatography from Tridacna crocea, Pocillopora or the dinoflagellate Amphidinium, showed similar absorption characteristics in different solvents. The extinction coefficient of crystalline peridinin in acetone was E1 cm1% 1340.3. Clam zooxanthellae (and the dinoflagellates Amphidinium and Gymnodinium) contained a much higher proportion of chlorophyll c than coral zooxanthellae.4. No chlorophyll decomposition products were found in any freshly prepared zooxanthellae preparations.