Seasonal changes in the freezing tolerance of the intertidal pulmonate gastropod Melampus bidentatus Say

1985 ◽  
Vol 63 (9) ◽  
pp. 2021-2025 ◽  
Author(s):  
Stephen H. Loomis

The mean lethal temperature of Melampus bidentatus Say ranged from −5 °C in July to −13 °C in December. The percentage of tissue water frozen measured at the mean lethal temperatures was 3% for snails collected in the summer and 74.9% for snails collected in the winter. The supercooling point of the whole snails ranged from −9 °C in September to −6.4 °C in February. The presence of an ice nucleator is indicated by an increase in the supercooling point of the haemolymph from −11.5 °C in the fall to −7.5 °C in the winter. Water content in the snails varied from 2.6 mg water/mg dry weight to 3.6 mg water/mg dry weight; however, there was no correlation between low water contents and an increase in freezing tolerance. Whole animal glycerol contents ranged from 1.14 to 2.96 μmol/g fresh weight and proline contents ranged from 1.20 to 2.19 μmol/g fresh weight. Sorbitol and trehalose were not detected.

1982 ◽  
Vol 33 (3) ◽  
pp. 559 ◽  
Author(s):  
BT Steer

Onion bulbs (Allium cepa L. cv. Creamgold), grown in a phytotron from seed, had a dry weight as percentage of fresh weight that decreased as growth temperatures increased from 22/16 to 33/28�C day/night. There were no significant differences between growth temperatures in the fructose, sucrose or fructan content and, although glucose content was higher at high temperatures, there was no correlation of total carbohydrate content with growth temperature. The sum of fructose, glucose and sucrose per unit tissue water was constant between temperatures, suggesting that the mono- and disaccharide content may control the bulb water content. These results, from controlled-environment tests, predict that in the field the best yield of dry weight as a percentage of fresh weight will be obtained at low growth temperatures.


1981 ◽  
Vol 59 (12) ◽  
pp. 2698-2706 ◽  
Author(s):  
Mark W. Schonbeck ◽  
J. Derek Bewley

Samples of the moss Tortula ruralis were desiccated either rapidly or slowly to different tissue water contents to determine the limits of desiccation tolerance. Experimental samples were rehydrated rapidly by contact with wet filter paper, and gas exchange, chlorophyll content, electrolyte efflux, and linear growth rate were compared with those of control samples. Drying to 0.30–0.089 g H2O∙g dry weight−1 did not significantly affect the moss. Slow drying to 0.058–0.008 g H2O∙g dry weight−1 caused temporary increases in dark respiration and electrolyte leakage, and a slight inhibition of growth. Rapid drying of the same water contents caused visible injury, reduced total chlorophyll and the ratio of chlorophyll a:b, greatly enhanced electrolyte efflux, and severely inhibited gross photosynthesis and linear growth. The damaging effects of rapid drying could be eliminated either by partial desiccation for 1–3 h before rapid drying, or by placing the dry moss in a 100% relative humidity (RH) atmosphere for 1–5 h before rehydration.Tortula ruralis demonstrated greater drought tolerance than many other bryophytes, algae, seeds, and desert angiosperms, and is clearly capable of surviving any drought which might occur in its natural habitat.


1983 ◽  
Vol 101 (3) ◽  
pp. 741-748 ◽  
Author(s):  
R. A. Leigh ◽  
A. E. Johnston

SUMMARYThe effects of N, P, K and Na silicate fertilizers, and drought on the concentrations of K in the dry matter and tissue water of field-grown spring barley crops have been investigated. Percentage K in dry matter depended on the amounts of N, P, K or water received by the crops and was linearly related to fresh weight to dry weight ratio, but the slope of this relationship depended on whether or not the crops received K. Expressing K concentrations on the basis of tissue water eliminated differences between crops, except for those given insufficient K. Barley crops given fertilizer K maintained K concentrations in their tissue water of about 200 mmol/kg tissue water for most of the growth period but crops grown without K had only 50–70 mmol/kg tissue water. The results indicate that K concentrations in the tissue water are a more reliable indicator of tissue K status than % K in dry matter.Decreases in crop K content resulting from poor K supply were balanced by increases in Na and Ca (but not Mg) contents so that total cation concentrations in the tissue water were similar in low and high K crops. The extra Na and Ca are probably primarily involved in maintaining charge balance for anion absorption but once in the plant they may also substitute for K in its osmotic role.


Author(s):  
Ferit Özen ◽  
Gülsüm Yaldız ◽  
Mahmut Çamlıca ◽  
Halit Aşkın ◽  
Abdurrahman Başol

This research was carried out in the climate chamber in order to determine the effect of hydrosols obtained from sage grown with selenium application on germination of fenugreek and coriander seeds. Different concentrations of sage hydrosol (2.5, 5, 7.5 and 10 ml) and purified water used as control were applied to the fenugreek and coriander seeds. Germination rate, fresh weight, dry weight, root length, shoot length and root / shoot ratio of fenugreek and coriander seeds were applied. Variance analysis was performed according to the split plot design and the mean values were compared with LSD test. According to the results of the research; germination rate of fenugreek seeds 38.35-51.00%, fresh weight 0.04-0.12 g, dry weight 0.001-0.035 g, root length 0.71-2.02 cm, shoot length 1.27-3.20 cm, root/shoot ratio varied between 0.34-0.82, germination rate of coriander seeds 18.61-39.21%, fresh weight 0.0011-0.034 g, dry weight 0.004-0.030 g, root length 1.5-4.58 cm, shoot length 1.08-3.69 cm, root/shoot ratio 0.47-2.51 were found. The highest germination rate was obtained in 2.5 ml dose of sage hydrosol (51.00%) in fenugreek seeds and the highest germination rate was found in 7.5 ml dose of sage hydrosol (39.21%) in coriander seeds.


2020 ◽  
Vol 51 (Special) ◽  
Author(s):  
AL-Samarai & et al.

The current study  was carried out at the Fields belongs of Horticulture  Department, Collage of Agricultural Engineering Science, University of  Baghdad, Al-Jadiriyah for the spring season 2016 -2017 to study the effect for  inoculation mycorrhizae and  folair application  with bio stimulators and their interaction in the growth characters of  (local okra  ptera). A factorial experiment  (2  in randomized complete block design (RCBD), the experiment included (12) treatment  Distributed  in three  replicates. The three factors used in this experiment included . The inoculation with control (C) Mycorrhizae  ( M ) , Biozyme  (B ) ( B1 2cm3.L-1), ( B2 4cm1-.L-1) , Phosphalas (P) (P 2cm3.L-1),  ( M + B1), ( M + B2), (P + M ), ( P + B1), (P + B2), ( M + P + B1), ( M + P + B2). The data were analyzed according to the design followed and the mean was tested by the lowest significant difference at 0.05%. The results showed a significant increase in the studied traits .  The results showed that the three factors and their interactions had significant effects on most of the growth characters measured. The inoculation with the Mycorrhizae  , Biozyme  and  Phosphalas was superior in giving higher values of  plant height  (M1B2P1) 120.00 cm,  Main branches number  per plant 13.00,  number of  leaves 197.0  (Leaf .plant -1),  leaf area  394.0 (dcm2. Leaf ),  fresh weight  of vegetative 3200 (kg. plant-1)  Dry weight of vegetative 209.0 ( g . plant-1), number of  nodules on the stem 41.33  (nod. plant -1),  relative chlorophyll content  (SAPD) respectively. The M1B2P0 combination treatment recorded the highest values of  secondary branches number  per plant 10.33. The M1B1P0 treatment recorded the highest values of diameter of stem 4.03 (cm).   


Genetika ◽  
2014 ◽  
Vol 46 (3) ◽  
pp. 815-829
Author(s):  
Mahdi Bayat ◽  
Reza Darvishzadeh ◽  
Farough Soleimani ◽  
Seyyed Alavi

In the present work the relationships between yield and its related traits were investigated in tobacco genotypes under normal and abiotic stress conditions (Orobanche aegyptiaca weed) at Urmia Tobacco Research Centre, Iran, during 2006-2009 cropping seasons. The experimental design was a randomized complete block design (RCBD) with three replications in each condition every year. Analysis of variance revealed extent genetic variability among the genotypes for most of the traits studied. In comparison with normal condition, the mean value of studied traits decreased in stress condition. LAI and FD showed the maximum and minimum diminution in the mean values under stress condition compared to normal one so known as more sensitive and more tolerant traits, respectively. Based on CV values, the traits FD and DLYP showed the minimum and maximum variation among traits in both normal and stress conditions. Correlation analysis revealed significant and positive correlations between DLYP with all studied traits in both normal and stress conditions. Path analysis detected the traits including biomass, APDW and DWR as the first-order variables at normal condition and biomass, APDW, DWR and harvest index as the first-order variables under abiotic stress condition. Based on results, the traits such as biomass, APDW, DWR detected as more important factors in both conditions can be used in tobacco breeding programs for increasing yield. Abbreviation: aerial part fresh weight without leaves weight (APFW), aerial part dry weight without leaves weight (APDW), biomass (BIO), coefficient of variation (CV), dry weight of root (DWR), flowering date (FD), fresh weight of leaf (FWL), fresh weight of root (FWR), harvest index (HI), leaf area index (LAI), dry leaf yield per plant (DLYP), number of leaf (NL), plant height (PH), randomized complete block design (RCBD), standard deviation (Std).


2007 ◽  
Vol 13 (4) ◽  
pp. 269-275 ◽  
Author(s):  
M.A. Sahari ◽  
M. Barzegar ◽  
R. Radfar

Thirty-four date (Phoenix dactylifera L.) varieties, from start of Tamr stage of maturity, were analyzed for moisture, protein, lipid and ash. The mean percent of moisture, protein, lipid and ash were 29.35, 3.3, 0.42 and 2.25 g/100 g (fresh weight basis), respectively. Predominant sugars were fructose (12.62—43.31 g/100 g) and glucose (16.41—54.23 g/100 g, fresh weight basis). Sucrose was not practically detected in most varieties (excepting in Zark variety). Mineral elements such as Na, Mg, K and Ca were determined by ICP atomic spectroscopy and their amounts were in the range of 4.46—47.74, 18.44—79.35, 203.61—982.97 and 23.24—73.85 mg/100 g (dry weight basis), respectively. These results were generally in agreement with those reported previously for some other varieties grown in the other dates producing countries. A few differences will be related to date variety, agro-climatic and environmental conditions.


1991 ◽  
Vol 71 (2) ◽  
pp. 565-569 ◽  
Author(s):  
B. J. O'Connor ◽  
L. V. Gusta ◽  
S. P. Paquette

The freezing tolerance of downy (Bromus tectorum L.) and Japanese (Bromus japonicus) brome were compared to Norstar winter wheat (Triticum aestivum L.) collected from similar sites. From December to April of 1987 downy brome was either equal to or superior in freezing tolerance to the winter wheat. Of the three species, Japanese brome was slightly less hardy in December but was of equal freezing tolerance in March and April. There was no correlation between freezing tolerance and tissue water content or tissue dry weight in the three species. These two bromes may become a serious weed in winter wheat because their cold hardiness is either equal or superior to our hardiest winter wheat cultivars. Key words: Downy brome, Japanese brome, winter wheat, freezing tolerance


1982 ◽  
Vol 60 (8) ◽  
pp. 1945-1950 ◽  
Author(s):  
Thierry Pilorge

The diet of Lacerta vivipara was estimated in the laboratory by determining the relationship between fecal production and food intake. Transposed to free-living individuals, this relationship between the daily consumption C in milligrams of dry weight and the total fresh weight of lizards in grams becomes C = 20.4 W0,85. By knowing the number of days during which lizards can eat, the assimilation rate, the weight increase, the mean weight of the tail, the rate of autotomy, and the weight of a brood, the individual energy budget has been established for each sex according to age. The proportion of the assimilated biomass used for growth reaches a peak in young lizards, then decreases regularly to a negligible degree in older animals. The energy used for reproduction is low at first in primiparous females but becomes three times as great in older females.[Traduit par le journal]


Sign in / Sign up

Export Citation Format

Share Document