scholarly journals Desiccation tolerance and DNA integrity in Eugenia pleurantha O. Berg. (myrtaceae) seeds

2008 ◽  
Vol 30 (1) ◽  
pp. 175-180 ◽  
Author(s):  
Tathiana Elisa Masetto ◽  
José Marcio Rocha Faria ◽  
Antonio Claudio Davide ◽  
Edvaldo Aparecido Amaral da Silva

The aim of this study was to assess the desiccation tolerance and DNA integrity in Eugenia pleurantha seeds dehydrated to different moisture contents (MCs). Seeds extracted from mature fruits were submmited to drying in silica gel and evaluated at every five percentual points of decrease from the initial MC (35.5%, fresh weight basis). The effects of dehydration on seeds were verified through germination tests and DNA integrity assessment. Undried seeds achieved 87% germination, value reduced to 36% after being dried to 9.8% MC. When dried slightly more, to 7.4% MC, seeds were no longer able to germinate, suggesting an intermediate behavior in relation to desiccation tolerance. It was observed DNA degradation in seeds with 7.4% MC, which might have contributed to the loss of seed germination.

2008 ◽  
Vol 30 (2) ◽  
pp. 51-56 ◽  
Author(s):  
Tathiana Elisa Masetto ◽  
José Marcio Rocha Faria ◽  
Antonio Claudio Davide ◽  
Edvaldo Aparecido Amaral da Silva

The aim of this study was to assess the desiccation tolerance and DNA integrity in Eugenia pleurantha seeds dehydrated to different moisture contents (MCs). Seeds extracted from mature fruits were dried in silica gel and evaluated at every five percentual points of decrease from the initial MC (35.5%, fresh weight basis). The effects of dehydration on seeds were verified through germination tests and DNA integrity assessment. Undried seeds achieved 87% germination, value reduced to 36% after being dried to 9.8% MC. When dried slightly more, to 7.4% MC, seeds were no longer able to germinate, suggesting an intermediate behavior in relation to desiccation tolerance. DNA degradation was observed in seeds with 7.4% MC, which might have contributed to the loss of seed germination.


2004 ◽  
Vol 14 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Lars Christian Mortensen ◽  
Dolores Rodríguez ◽  
Gregorio Nicolás ◽  
Erik Nymann Eriksen ◽  
Carlos Nicolás

Dormancy and desiccation tolerance were studied inFagus sylvaticaseeds subsequent to 0–26 weeks of either moist prechilling (5°C) or warm (15°C) pretreatment at a restricted water content of 34% (fresh weight basis), i.e.c. 5% below full imbibition. After the pretreatments, seeds were either fully imbibed at 5 or 15°C, or dried for 7 d to around 13% moisture content and then fully imbibed at 5°C. Most of the dormancy was released after 5 weeks of prechilling, with nearly 70% of the seeds germinating at 15°C, and dormancy was fully released after 11 weeks of prechilling. Most of the seed desiccation tolerance, measured as the final germination percentage for dried seeds, was lost between 11 and 13 weeks of prechilling. A further decline in desiccation tolerance was recorded from 13 to 19 weeks, with a moderate recovery after 26 weeks. Germination was compared with the expression of a previously described abscisic-acid-responsive GRPF1 mRNA for a glycine-rich protein inF. sylvatica. There was a clear decline in accumulation of the transcript in seeds during prechilling, but not during the warm pretreatment. The amount of GRPF1 expression correlated significantly (P< 0.001) with dormancy status.


2000 ◽  
Vol 10 (3) ◽  
pp. 329-339 ◽  
Author(s):  
Françoise Corbineau ◽  
Mari Ange Picard ◽  
Jean-Albert Fougereux ◽  
Fabienne Ladonne ◽  
Daniel Côme

Germination and carbohydrate metabolism were studied in fresh developing pea (Pisum sativum L., cv Baccara) seeds and after artificial drying at 25°C and various relative humidities (20, 75 and 99% RH) to investigate whether the occurrence of desiccation tolerance was related to sucrose, raffinose and stachyose contents. Seeds became completely tolerant to fast drying at 25°C and 20% RH a few days after the end of reserve accumulation, i.e. when their moisture content dropped to approx. 50% (fresh weight basis). This acquisition of desiccation tolerance was associated with an accumulation of raffinose and stachyose, the latter being more abundant in the embryonic axis than in the cotyledons. The (raffinose+stachyose)/sucrose ratio increased during seed development and reached 1.1 in the axis and 0.2 in the cotyledons just before the onset of desiccation tolerance. When the natural acquisition of desiccation tolerance occurred on the mother plant, artificial drying of isolated seeds induced an increase in oligosaccharide content in the cotyledons. Immature seeds, the moisture content of which was higher than about 60% (fresh weight basis), did not tolerate fast drying (25°C and 20 or 75% RH). Such drying did not result in the synthesis of stachyose and induced an increase in electrolyte leakage, a decrease in the ability of seeds to convert 1-aminocyclopropane 1-carboxylic acid (ACC) to ethylene and an increase in ethane synthesis, thus indicating a deterioration of cell membrane properties and lipid peroxidation. In contrast, immature seeds tolerated drying either in the pods or at 25°C and 99% RH, and such drying induced a decrease in sucrose content, an increase in oligosaccharide content and a (raffinose+stachyose)/sucrose ratio higher than around 1. Soluble sugar contents of dried immature seeds depended on the conditions of dehydration. In cotyledons, the (raffinose+stachyose)/sucrose ratio reached 0.61 when seeds were dried at 25°C and 99% RH, whereas it was as low as 0.15 when drying was performed at 25°C and 20% RH. All the results obtained are consistent with the concept that oligosaccharides may well be involved in the protection of membranes during dehydration.


Author(s):  
Pinkal Patel ◽  
Ratna Trivedi

The Milky mushroom, Calocybe Indica was cultivated on different agricultural substrate, paddy straw, wheat straw, sugarcane trace and mango dry leaves. The spawning was done by sterilization of all the four substrate. The bags were kept in mushroom growing room with the maintenance of temperature and humidity 30̊ c-35̊ c and 70-80 % respectively. The minimum days requires for completion of spawn run (18.4 days), primordial formation (25.2 days) and days for first harvest (32.4 days) was first observed on cultivation with Paddy straw.  The maximum yield on fresh weight basis and biological efficiency (134.86 %) was also found to be as the same treatment with the Paddy straw as a substrate. The biological efficiency of wheat straw was at par with Sugarcane trace as substrate which was 85.07 % and 85.02 % respectively.


1968 ◽  
Vol 46 (7) ◽  
pp. 921-928 ◽  
Author(s):  
D. J. Durzan

In late August during the onset of dormancy in spruce, seasonal levels of soluble nitrogen, rich in arginine, were high. On a fresh weight basis, diurnal levels of total soluble nitrogen and most component amino acids in roots, buds, and leaves showed maxima, one at sunrise and another in the afternoon or near sunset.Arginine and glutamine in the different plant parts contributed 44 to 83% to the alcohol-soluble nitrogen. In buds and leaves, percentage of arginine remained high and decreased slightly at midday, whereas in roots a continual drop occurred. In all organs examined, changes in glutamine reflected the double maxima of total soluble nitrogen and were greatest in roots.On a fresh weight basis, most amino acids accumulated at sunrise and near sunset; however a few especially in leaves, increased at midday, e.g. glutamic and aspartic acid, lysine, γ-aminobutyric acid, and serine.Comparison of levels of free guanidino compounds in different organs showed remarkable out-of-phase patterns. Levels of these compounds are known from 14C-arginine studies to be closely related to the metabolism of arginine.


1999 ◽  
Vol 77 (3) ◽  
pp. 323-332
Author(s):  
Suzy Y Rogiers ◽  
N Richard Knowles

Changes in respiration and ethylene production rates of nine maturity classes of saskatoon (Amelanchier alnifolia, Nutt.) fruit after harvest were compared with those of fruit maturing and ripening on the plant. During ripening on the plant, ethylene production increased on a whole-fruit and fresh-weight basis, while respiration increased substantially on a whole-fruit basis but remained constant on a fresh-weight basis. Fruit harvested at the greenish yellow to pink stages (maturity classes four and five, respectively) increased their ethylene production until 15-20 h after harvest, and this was coincident with ripening to maturity class seven and thus a color change to red. Ethylene production then declined over the next 15 h. Respiration rates of harvested immature, mature, and ripe fruits declined over 5 days, except for a relatively brief 8-12% rise starting 15-20 h after harvest. This brief increase in respiration was characteristic of fruit of all maturity classes, likely reflecting a wound response associated with harvest rather than a ripening-induced change in metabolism. Continuous treatment of attached or detached fruit with propylene or ethylene in an open airflow system did not induce an increase in respiration earlier, relative to control fruit. The respiratory response of saskatoon fruit during postharvest ripening was thus very different from that of fruit that ripened on the plant. Thus, the increase in respiration associated with ripening could only be demonstrated on a whole-fruit basis if fruit remained on the plant. Preharvest and postharvest changes in ethylene production during ripening also differed but were both consistent with climacteric ripening.Key words: Amelanchier alnifolia, ethylene, ripening, saskatoon fruit.


1970 ◽  
Vol 43 (4) ◽  
pp. 483-494 ◽  
Author(s):  
M Moshfekus Saleh-e-in ◽  
Abida Sultana ◽  
M Abul Hossain ◽  
Mainul Ahsan ◽  
Sudhangshu Kumar Roy

Anethum sowa L. (Dill) stem portions were analyzed for its macro and micro elemental concentration by XRF spectrometry collected from different places of Bangladesh. The plants were collected when those were 35 cm in height i.e. within 40-45 days of sowing. Results of proximate analyses showed that the stem parts contained highest level of moisture (93.67), ash (1.62) and dry matter (30.77%) on fresh weight basis (g/100g). The highest level of mineral contents were Ca(478.50±6.22), K(336.65±3.26), Cl(153.92±3.26), Na(114.86±1.38), S(96.65±1.76), Mg(63.96±1.15), P(49.41±0.74), Al(41.75±0.71), Fe(34.57±1.33), Si(31.03±0.18), Ni (11.98±0.22) and Ti (3.75±0.28) in mg/100g on fresh weight basis. Cu, Sr, Rb, Zn, Ba and Zr were present in small amount and Y, Cu and Mn were present in trace amount. However, the toxic elements like Co, Pb, As and Hg were not found in the present study. Presence of higher amounts of mineral contents in the stem parts could potentially be consumed as supplement as human diets or livestock feed as well as pharmaceutical preparation. Key words: Anethum sowa L., XRF spectrometry, Dill, Condiment, Macro and micro elements, Elemental composition.     doi: 10.3329/bjsir.v43i4.2238   Bangladesh J. Sci. Ind. Res. 43(4), 483-494, 2008


1981 ◽  
Vol 59 (8) ◽  
pp. 884-886 ◽  
Author(s):  
Adrien R. Beaudoin ◽  
Pierre St-Jean ◽  
Ginette Girard

Recent observations have confirmed the existence of more than one pool of secretory proteins in the rat pancreatic tissue. To determine if these different pools could be located in the different regions of the rat pancreas, the amylase and chymotrypsin contents have been measured in the biliary, duodenal, gastric, and splenic regions. On a tissue DNA content, protein content, or a fresh weight basis, the proportions of these two enzymes are comparable in the four regions. It is therefore postulated that heterogeneity of enzyme composition exists either within these regions or within the acinar cell itself.


2011 ◽  
Vol 29 (11) ◽  
pp. 1164-1170 ◽  
Author(s):  
Jonathan W. C. Wong ◽  
Ammaiyappan Selvam ◽  
Zhenyong Zhao ◽  
S. M. Yu ◽  
Alex C. W. Law ◽  
...  

Composting sewage sludge alone would reduce the decomposition efficiency due to free limited porosity in sludge. To alleviate this, the use of horse stable straw bedding waste (HSB) was evaluated as a co-composting material with sewage sludge in a 10 tonnes day−1 in-vessel composter for a period of 7 days before curing in a static aeration pile. Sludge was mixed with HSB at 1 : 1.5 (HSL) and 1 : 2.9 (LSL) on a fresh weight basis. After a composting period of 56 days, both mixing ratios demonstrated to be feasible with LSL having a better organic decomposition and a shorter time to reach maturity. The overall decomposition rates were 52.0 and 58.9% (dry weight basis) for HSL and LSL, respectively. In both treatments, temperature in the in-vessel composters could reach 65°C, which was sufficient to remove the pathogens. Although both products were free of pathogens, HSL exhibited a higher ammoniacal nitrogen contents but a lower seed germination index than that of LSL indicating a higher phytotoxicity and a longer curing period would be required. It can be concluded that HSB provided a better composting conditions at a mixing ratio of 1 : 2.9


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