Water vapour uptake and drought resistance in immobile instars of Parasitengona (Acari: Prostigmata)

1998 ◽  
Vol 76 (9) ◽  
pp. 1741-1754 ◽  
Author(s):  
Andreas Wohltmann
Keyword(s):  
Water Vapour ◽  
Drought Resistance ◽  
Water Loss ◽  
Fresh Mass ◽  
Osmotic Regulation ◽  
Atmospheric Moisture ◽  
Ground Plan ◽  
Stem Species ◽  
Water Vapour Uptake ◽  
Reduced Water

Eggs and protonymphs of a number of terrestrial Parasitengona were tested for drought resistance and their ability to take up atmospheric moisture. Species of the Erythraeoidea display higher drought resistance in both instars than species of the Trombidioidea. This is achieved by evolutionary modifications of the ground plan of the Parasitengona, including reduction of body openings and additional sealing of others with lipids, resulting in reduced water loss. Water vapour uptake is not evident in erythraeoid eggs or protonymphs but has been observed in the Trombidioidea and probably constitutes a characteristic of at least the stem species of the terrestrial Parasitengona. The resulting increase in fresh mass is about 50% before the protonymph stage begins; its role is probably not related to drought resistance or osmotic regulation. Instead, it presumably serves to extend the cuticle and thus provides more space for the development of the subsequent instar.

scholarly journals HYDROCOOLING EFFICIENCY ON POSTHARVEST CONSERVATION AND QUALITY OF ARUGULA

2019 ◽  
Vol 6 (4) ◽  
pp. 36-41
Author(s):  
Elaine Gleice Silva Moreira ◽  
Scarlet Aguiar Basílio ◽  
Mariany Dalila Milan ◽  
Natália Arruda ◽  
Katiane Santiago Silva Benett
Keyword(s):  
Mass Loss ◽  
Respiratory Rate ◽  
Shelf Life ◽  
Water Loss ◽  
Cold Water ◽  
Subjective Evaluation ◽  
Storage Period ◽  
Titratable Acidity ◽  
Fresh Mass ◽  
Soluble Solids

Arugula is mainly cultivated by small producers, being a leafy vegetable susceptible to water loss and wilting after harvest, which may result in changes in appearance, texture, color (yellowing), and nutritional value of the product. Hydrocooling is a cooling method that stands out for being simple, practical and efficient. Its use is to reduce the temperature and respiratory rate of vegetables after harvesting by immersion in ice or cold water, so they can be packed and stored. This study was conducted to evaluate the hydrocooling efficiency when associated with the storage period in the postharvest shelf life of arugula leaves. Arugula leaves were subjected to ten days of storage, and measurements were taken at 0, 2, 4, 6, 8 and 10 days. The experimental design was completely randomized in a 3 × 6 factorial scheme, consisting of three hydrocooling treatments [control (without cooling), and hydrocooling at 0 °C and 10 °C] and for six storage periods (0, 2, 4, 6, 8 and 10 days) with three replicates. Fresh mass loss, soluble solids, titratable acidity, pH and subjective evaluation of product appearance were measured. Hydrocooling at 0 °C proved to be the most appropriate treatment when compared to control, as reported by the values of fresh mass loss, soluble solids, and titratable acidity. Hydrocooling to 0 °C slowed leaf water loss (lower respiratory rate) and resulted in better overall leaf appearance up to the sixth day of storage, thereby increasing shelf life of arugula leaves.

The effect of respiratory pattern on water loss in desiccation-resistant Drosophila melanogaster.

1998 ◽  
Vol 201 (21) ◽  
pp. 2953-2959 ◽  
Author(s):  
A E Williams ◽  
T J Bradley
Keyword(s):  
Drosophila Melanogaster ◽  
Water Loss ◽  
Loss Rate ◽  
Extended Period ◽  
Peak Height ◽  
Respiratory Pattern ◽  
Water Loss Rate ◽  
Selection For ◽  
Reduced Water ◽  
Co2 Release

We measured CO2 and H2O release from individual fruit flies from five populations of Drosophila melanogaster selected for resistance to desiccation (D flies). Our previous work found that these flies survive for an extended period in dry air, have an increase in the peak height and frequency of CO2 release, as measured by the standard error of a linear regression (SER) of CO2 release for the entire survival period, and have reduced water loss rates (VH2O) compared with their control or ancestor populations. In the present study, we examined the following respiratory characteristics: VCO2, VH2O, the SER of CO2 release and the ratio of VCO2 to VH2O in the D flies. Correlations between these characters were calculated in order to determine the effect of respiratory pattern on water loss. We found that, within the D flies, neither periodic release of CO2 nor an increased SER for CO2 release was associated with reduced water loss. In addition, an increased SER was positively correlated with both an increased water loss rate and a decreased survival time. Therefore, although selection for desiccation resistance leads to both an increased SER and a decreased rate of water loss in the D flies, the increased SER does not significantly reduce respiratory water loss.

Relationships among Fresh Mass, Incubation Time, and Water Loss in Japanese Quail Eggs

The Condor ◽  
1991 ◽  
Vol 93 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Pamela A. Martin ◽  
Todd W. Arnold
Keyword(s):  
Japanese Quail ◽  
Incubation Time ◽  
Water Loss ◽  
Fresh Mass

Responses of Pests to Fumigation. IV.—The responses of Calandra spp. to Reduced Pressures

1953 ◽  
Vol 44 (4) ◽  
pp. 651-656 ◽  
Author(s):  
A. K. M. El Nahal
Keyword(s):  
Water Vapour ◽  
Direct Effect ◽  
Water Loss ◽  
Direct Action ◽  
Practical Importance ◽  
Reduced Pressures

The direct action of reduced pressures, in the absence of any fumigant, on C. oryzae and C. granaria have been investigated in glass chambers of about 1 litre capacity. C. oryzae is sufficiently sensitive to make the direct effect of reducing the pressure within the range 2 to 10 cm. mercury of some practical importance, but C. granaria is more resistant. Mortality of both species increases for exposure periods of up to 8 hr. and for increased temperatures from 20°C. to 28°C. A large part of the observed mortality must be associated with enhanced water-loss from the insects at reduced pressures, as little response occurs when the atmosphere is kept saturated with water-vapour.

Seasonal and diurnal variation in the stomatal conductance and paraheliotropism of tedera (Bituminaria bituminosa var. albomarginata) in the field

2013 ◽  
Vol 40 (7) ◽  
pp. 719 ◽  
Author(s):  
Kevin Foster ◽  
Megan H. Ryan ◽  
Daniel Real ◽  
Padmaja Ramankutty ◽  
Hans Lambers
Keyword(s):  
Stomatal Conductance ◽  
Drought Resistance ◽  
Water Loss ◽  
Incident Light ◽  
Leaf Water ◽  
Leaf Angle ◽  
Leaf Water Content ◽  
Bituminaria Bituminosa ◽  
Pasture Plant ◽  
Perennial Legumes

The mechanisms of drought resistance in perennial legumes are poorly understood. We explored the diurnal and seasonal variation (May, August, February) in stomatal conductance (gs) and paraheliotropism of three tedera accessions (Bituminaria bituminosa (L.) C.H. Stirton var. albomarginata) and lucerne (Medicago sativa L.), both perennial legumes, grown in the field. For the tedera accessions, there was a significant reduction in gs during the day in May (late autumn) and February (summer), but there was little reduction for lucerne. The peak leaf angle in the tedera accessions ranged from <40° to 70°, whereas for lucerne, the leaf angle was nearly parallel to incident light at 85°. Leaf water-use efficiency, relative leaf water content and leaf retention were higher for the tedera accessions than for lucerne in February. These results highlight the superior drought resistance of tedera compared with lucerne. The reduction in gs over the day in tedera shows the capacity of this species to reduce water loss quickly when conditions for CO2 fixation relative to water loss are highly unfavourable. The high retention of leaves in summer by tedera is a valuable trait for a perennial pasture plant in Mediterranean environments. Leaf folding, combined with effective stomatal control in summer, provides tedera with a set of physiological responses that confer high drought resistance.

scholarly journals Topochemical acetylation of cellulose nanopaper structures for biocomposites: mechanisms for reduced water vapour sorption

Cellulose ◽  
2014 ◽  
Vol 21 (4) ◽  
pp. 2773-2787 ◽  
Author(s):  
Ana Gisela Cunha ◽  
Qi Zhou ◽  
Per Tomas Larsson ◽  
Lars A. Berglund
Keyword(s):  
Water Vapour ◽  
Water Vapour Sorption ◽  
Vapour Sorption ◽  
Cellulose Nanopaper ◽  
Reduced Water
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