Possible mechanism of gibberellin-induced chlorosis in lettuce seedlings

1973 ◽  
Vol 51 (1) ◽  
pp. 175-184 ◽  
Author(s):  
Gaurangakumar Das

Effects of gibberellin A3 (GA) on growth, pigments, protein, and nucleic acid content of the cotyledons of lettuce seedlings (Lactuca sativa L. cv. Grand Rapids) are reported. GA treatment increased both the total shoot and cotyledon fresh weights, and decreased chlorophyll content per cotyledon and on a dry weight basis. GA also decreased the protein content of the cotyledon, but increased the level of RNA and DNA measured on a dry weight basis. The hormone had no effect on the pheophytin: chlorophyll ratio, but increased the ratios of chlorophyll a: chlorophyll b, phytol: chlorophyll, and carotene: chlorophyll. GA also increased the sugar content of the cotyledons. Treatment of excised cotyledons with glucose had an effect similar to that of GA on chlorophyll and protein content. The data are discussed in relation to the mechanism of GA-induced chlorosis.

1973 ◽  
Vol 51 (1) ◽  
pp. 121-125 ◽  
Author(s):  
Gaurangakumar Das

The influence of calcium supply on the chlorophyll, carotene, nucleic acid, and protein content in Scenedesmus obtusiusculus Chod. was investigated. Evidence showed that upon addition of calcium-starved cells to a culture medium containing calcium, the levels of all these components increased slowly for 15 h. During the next 33 h chlorophyll and carotene content increased more rapidly, and the chlorophyll a:b ratio also increased. During this growth period, both RNA and protein content increased linearly whereas DNA content did not increase on a dry weight basis throughout the period of observation.


HortScience ◽  
2016 ◽  
Vol 51 (9) ◽  
pp. 1144-1147 ◽  
Author(s):  
Thomas E. Marler ◽  
Nirmala Dongol

The profile of nonstructural carbohydrates (NSC) was quantified to determine sugar and starch relationships of megagametophyte tissue during Cycas micronesica K.D. Hill seed ontogeny. Field work occurred in northern Guam where megastrobili were marked and dated as they emerged from stem apices of plants in a natural population. Seeds were harvested beginning 6 months after megastrobili emergence and continuing until 28 months, and gametophyte tissue was separated from the remainder of each seed. Carbohydrates within lyophilized gametophyte tissue were quantified by high-pressure liquid chromatography. The levels of glucose and fructose declined from a high at 6 months to a homeostasis at 11 months, and the levels of sucrose similarly declined from 6 months to a homeostasis at ≈14 months. Starch content exceeded sugar content and increased from 6 months to reach a homeostasis at ≈18 months. Maltose was not detected in any sample. Stoichiometric quotients changed dramatically until ≈14 months, when they became fairly stable until 28 months. Starch concentration was ≈5-fold greater than sugar concentration at 6 months, and increased to ≈15-fold greater than sugar concentration by 28 months. Total NSC in mature megagametophytes was almost 70% on a dry weight basis. Our results are in agreement with the biological function of this haploid tissue, as copious carbohydrate resources are readily available to support embryo and seedling growth.


1966 ◽  
Vol 12 (4) ◽  
pp. 677-682
Author(s):  
Jacques de Repentigny ◽  
Sorin Sonea ◽  
Armand Frappier

Cultures of Staphylococcus aureus were grown in the presence of five different antimetabolites (5-fluorodeoxyuridine, aminopterin, 8-azaguanine, mitomycm-C, 5-fluorouracil) active against ceil walls and (or) nucleic acids. Fluorescence microscopy of smears stained with acridine orange revealed reddish and green cells in both treated and untreated cultures. There were less than 20% of reddish cells in untreated cultures and more than 40% in treated cultures. Treated cultures contained fewer viable organisms. All antimetabolites except mitomycin-C produced a diminution in the nucleic acids, chemically determined as percentage of dry weight of bacteria. Only 5-fluorouracil increased the RNA/DNA ratio. However, with ultraviolet microscopy at 260 mμ wavelength the absorption of reddish cells is much higher than that of the green cells, which, at the cellular level, seemed to indicate a greater nucleic acid content. With ultraviolet or with fluorescence microscopy we have obtained similar evidence of the cellular heterogeneity produced by antimetabolites in bacterial populations.


2016 ◽  
Vol 7 (1) ◽  
pp. 26 ◽  
Author(s):  
Ernesto López ◽  
Noé Becerra ◽  
Octavio Cano ◽  
Dora Zaleta ◽  
Jorge Acosta

In this paper the results obtained with a uniform yield trial including 22 bean genotypes grown in three states of Mexico are presented. Under experimental conditions, bred line DOR 390 resulted outstanding for its wide adaptation, high and stable yield (1041 kg/ha, bi=1.0 Sd2i=0) Under farmer’s conditions, DOR 390 (1214 kg/ha) was superior to commercial cvs, Negro Cotaxtla 91 (1142 kg/ha) and Jamapa (867 kg/ha); at neight locations of the humid tropics in the States of Tamaulipas, Veracruz and Chiapas, DOR 390 proved to be highly resistant in comparison to Negro Huasteco 81. Comparing Dor 390 to bred cvs. and landraces of the same commercial class, tropical black, Dor 390 showed and average protein content of 25%, on a dry weight basis, and the highest fiber content of the seven genotypes evaluated. DOR 390 was registered as a new cultivar in 1993, and made available to the farmers of the humid tropics in 1994, under the name of “Negro Tacana”.


Author(s):  
Pavan Kumar Kommuri ◽  
Naresh Mugada ◽  
Ramesh Babu Kondamudi

The research work was carried out to assess the dietary qualities of spiny lobsters collected from Visakhapatnam fishing harbour, situated on the northeast coast of Andhra Pradesh. The species selected were Panulirus homarus (Linnaeus, 1758), P. ornatus (Fabricius, 1798), P. versicolor (Latreille, 1804), and P. polyphagus (Herbst, 1793). The species were morphometrically measured, and their tissue was analyzed for the comparative proximate composition (Moisture, Protein, Lipid, and Ash) on a dry weight basis. Protein content was found to be high in all the lobster species. Highest protein content was observed in P. homarus (mg/g), followed by P. ornatus and P. versicolor (mg/g). Moisture percentage was 72.7, 75.7, 76.2, and 74.8% respectively. In addition, four minerals were analysed (Ca, Na, K, and Mg) in the present study. Calcium was observed maximum in all the species, and Magnesium was recorded minimum in all the lobsters.


2018 ◽  
Vol 10 (1) ◽  
pp. 122-127 ◽  
Author(s):  
Sweety Sihag ◽  
U. N. Joshi

A pot experiment was conducted to determine the effects of varying Cr (VI) levels [0.0–4.0 mg Cr (VI) kg-1 soil in the form of potassium dichromate] on the some quality parameters of sorghum Sorghum bicolor (L.). Quality parameters was measured in terms of protein content, chlorophyll content, and IVDMD ( In vitro dry matter digestibility) content at different growth stages, i.e. 35 DAS, 70 DAS and 90 DAS (Days after sowing) that were adversely affected with an increase in Cr (VI) levels from 0.0 to 4.0 mg Cr (VI) kg-1 soil. The decline in protein content 4.67 g/ kg dry weight at T4 was observed as compared to control (T1) ( 8.96 g/kg dry weight basis) at 35 DAS in leaves , Total chlorophyll content declined from 3.25 mg g-1 fresh weight (T1) to 2.40 mg g-1 fresh weight (T4) at 35 DAS and IVDMD content declined from 43.60 to 33.60 per cent dry weight basis with increment in chromium concentration. It is concluded that Cr (VI) at higher doses (4.0 mg Cr (VI) kg-1 soil) adversly affects the quality parameters of Forage sorghum Sorghum bicolor (L.) however, quality parameters are responsible for nutritive value of sorghum Sorghum bicolor (L.).


1955 ◽  
Vol 1 (7) ◽  
pp. 502-519 ◽  
Author(s):  
P. C. Fitz-James

The phosphorus fractions of the spores and young vegetative cells of B. cereus and B. megaterium were compared using the methods of Schneider and of Schmidt and Thannhauser. Differences were found, not only between the two types of cell, but also between the species studied. The spores of B. cereus and B. megaterium contained, on a dry weight basis, similar amounts of nucleic acid, yet the spores of B. megaterium contained twice as much total phosphorus as those of B. cereus. The excess phosphorus of B. megaterium spores was present as an acid and alkali insoluble residue and was made up of empty spore coats. While this same fraction accounted for only 4% of the total phosphorus of B. cereus spores it made up some 60% of that of B. megaterium. A similar fraction from vegetative cells was low in phosphorus. The spore coats of B. megaterium, in contrast to the cell walls were lysozyme-resistant. Cold acid-soluble and lipid phosphorus could be properly estimated only on disrupted spores. Disruption also proved essential for the ready extraction of spore nucleic acids with hot TCA, but did not greatly alter the solubility of the residue phosphorus. Ribosenucleic acid (RNA) comprised 50% of the total phosphorus in the spores of B. cereus (3–4% of the dry weight) but only 25% in B. megaterium spores. In both species the RNA of the vegetative forms accounted for a larger proportion of the total P of the cell. Ribonuclease digested the RNA of spores and vegetative cells to the same degree. The Schmidt and Thannhauser method was found more suitable than the Schneider method for the estimation of desoxyribosenucleic acid (DNA). The DNA content of B. cereus spores was about 1% of their dry weight; that of B. megaterium spores was slightly less. Some 12–20% of the phosphorus of B. cereus spores and 6% of that of the young vegetative cells was present as acid-labile (non-nucleic acid) phosphorus which exhibited some of the characteristics of polymetaphosphate.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Phanat Kittiphattanabawon ◽  
Sitthipong Nalinanon ◽  
Soottawat Benjakul ◽  
Hideki Kishimura

Pepsin-solubilised collagen from the skin of splendid squid (SC) was isolated, partially purified by salt precipitation and dialysis prior to characterisation. The yield of SC was 75.3% (dry weight basis). SC with high purity was obtained as shown by the distinct UV absorption peak at 232 nm and high hydroxyproline content. Total sugar content of SC was 4.70% (dry weight basis), which was higher than that of collagen from calf skin (CC) (1.45% dry weight basis) (P<0.05). Based on SDS-PAGE and elution profile, SC might contain the mixed types of collagen (type SQ-I and type SQ-II), in whichα- andβ-chains were the major components. SC was rich in glycine and had high content of imino acids (189 residues/1000 residues). The degradation induced by chymotrypsin and lysyl endopeptidase was more pronounced in CC, compared with SC. The maximum transition temperature (Tmax) of SC was 34.1°C, which was about 7°C lower than that of CC. Fourier transform infrared spectra revealed that the triple-helical structure of SC was predominant with the copresence of carbohydrate moieties. Therefore, the skin of splendid squid, a byproduct from squid processing, can be an alternative source for collagen production.


1980 ◽  
Vol 26 (5) ◽  
pp. 577-582 ◽  
Author(s):  
C. Breuil ◽  
G. B. Patel

Growth of Methanospirillum hungatii GP1 as determined by optical density measurement was comparable to growth assessed by cell dry weight, ribonucleic acid content, and deoxyribonucleic acid content. Cultivation of M. hungatii on synthetic medium containing mineral salts, vitamins, and acetic acid indicated that, on a dry weight basis, cell constituents such as protein (71%), ribonucleic acid (15.8%), deoxyribonucleic acid (1.6%), and total carbohydrate (3.2%) did not vary significantly with the growth phase. Cells grown in the synthetic medium supplemented with yeast extract and tryptone had slightly higher protein content (76%), but the concentrations of the other cell constituents were similar and did not fluctuate much during growth. Nitrogen limiting growth resulted in somewhat lower ribonucleic acid content as well as slightly higher protein content than that in cells grown in nonlimiting medium. Methanospirillum hungatii did not accumulate any of the commonly known reserve materials under nitrogen or carbon and hydrogen limiting growth.


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