The Desert Habitat | ScienceGate

Abstract Venezillo arizonicus (Mulaik & Mulaik, 1942) is the only oniscidean isopod native to the Southwest Desert Province of North America. In accordance with its desert habitat, we hypothesized that V. arizonicus would have a higher upper lethal temperature than mesic oniscideans. If oniscidean thermal tolerance is limited by an oxygen consumption-uptake mismatch (physiological hypoxia), as indicated by recent work with other land isopods, we further hypothesized that V. arizonicus would possess highly efficient pleopodal lungs, as defined by its capacity for metabolic regulation in reduced . Other adaptations to counter oxygen limitation at high temperatures could include reduced temperature sensitivity of metabolism (low ) and an overall reduction in metabolic rate. Thermal tolerance was measured using the progressive method of Cowles & Bogert and the catabolic rate of animals () was measured as a function of temperature and . The critical thermal maximum (CTmax) of winter-acclimatized animals was 43.0 ± 0.85°C, 1.6-2.6°C higher than published values for summer-acclimatized mesic oniscideans. The catabolic rate at 25°C was 1.50 ± 0.203 μl min−1 g−1, markedly lower than values determined for mesic Oniscidea (4-6 μl min−1 g−1) and was unaffected by hypoxia as low as 2% O2 (ca. 2 kPa). Catabolism was, however, quite sensitive to temperature, showing a mean of 2.58 over 25-42°C. The efficient pleopodal lungs and low metabolic rate of V. arizonicus will both tend to mitigate physiological hypoxia, consistent with the species’ high CTmax. A low catabolic rate may also be an adaptation to low habitat productivity and seasonally constrained activity patterns.

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The effect of the mirid bug Capsodes infuscatus on fruit production of the geophyte Asphodelus ramosus in a desert habitat

Oecologia ◽

10.1007/bf00328960 ◽

1993 ◽

Vol 93 (4) ◽

pp. 518-523 ◽

Cited By ~ 10

Author(s):

Y. Ayal ◽

I. Izhaki

Keyword(s):

Fruit Production ◽

Desert Habitat ◽

Mirid Bug

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The edge regions in tergites of the desert isopod Hemilepistus reaumuri: the transition from hard cuticle to flexible arthrodial membrane

Applied Physics A ◽

10.1007/s00339-020-03961-0 ◽

2020 ◽

Vol 126 (10) ◽

Author(s):

Franziska Ernst ◽

Helge-Otto Fabritius ◽

Erika Griesshaber ◽

Wolfgang W. Schmahl ◽

Andreas Ziegler

Keyword(s):

Mechanical Properties ◽

Anterior Part ◽

Section Plane ◽

Edge Region ◽

Posterior Edge ◽

Sagittal Section ◽

Desert Habitat ◽

Oriented Parallel ◽

Local Stiffness ◽

Hemilepistus Reaumuri

Abstract The arthrodial membrane is a thin and flexible type of cuticle that inserts at the edge regions of neighbouring rigid skeletal elements creating a flexible connection. In the present study, we analyzed the structure, mineral composition, calcite organization and local stiffness and hardness of edge regions that form transitions to the arthrodial membranes in the tergites of the desert isopod Hemilepistus reaumuri. For the transitions to the arthrodial membrane, the results show an increase in the thickness of the epicuticle at cost of the distal exocuticle and a calcite layer, an increase in the ratio of phosphorus to calcium and a decrease in the local mechanical properties. The posterior edge region contains an unusually large stack of unidirectionally oriented parallel fibrils projecting to the lateral sides. At the edge, it turns down into a long ventral cuticle overlapping an anterior part of the neighbouring tergite. It forms a thin arched gap between the tergites that can help reducing water loss through the arthrodial membrane and protects the arthrodial membrane upon predation. A thick ventral ridge near the transition to the arthrodial membrane carrying bristles can prevent sand grains from access to the arthrodial membrane. From the dorsal cuticle to the transition to the arthrodial membrane, calcite units become larger and single crystalline turning their c-axes orientation perpendicular to the sagittal section plane. Comparison with edge regions of the beach isopod Tylos europaeus reveal common characteristics of the edge region, but also specific adaptations to the desert habitat of H. reaumuri.

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Effects of light, temperature, salinity, and maternal habitat on seed germination of Aeluropus lagopoides (Poaceae): an economically important halophyte of arid Arabian deserts

Botany ◽

10.1139/cjb-2019-0096 ◽

2020 ◽

Vol 98 (2) ◽

pp. 117-125 ◽

Cited By ~ 5

Author(s):

Arvind Bhatt ◽

Sanjay Gairola ◽

María Mercedes Carón ◽

Andrea Santo ◽

Valentina Murru ◽

...

Keyword(s):

Control Group ◽

Distilled Water ◽

Light Regimes ◽

Aeluropus Lagopoides ◽

Percent Germination ◽

Recovery Percentage ◽

Desert Habitat ◽

Arid Desert ◽

Saline Solutions ◽

Germinated Seeds

In this study, salt tolerance during germination of Aeluropus lagopoides (L.) Trin. was tested using fresh seeds collected from three different maternal habitats under three thermoperiods and two light regimes. Additionally, we tested the ability of non-germinated seeds that had been exposed to different concentrations of NaCl to recover their germination in distilled water. The results showed a significant effect of seed source, temperature, and salinity, and some of their two- and three-way interactions on final germination and recovery percentage. The seeds from non-saline provenances had the highest percentages for germination (ca. 79%) under the 35/25 °C temperature regime, whereas the lowest percentages for germination (ca. 21%) was recorded for seeds from saline conditions under the 25/15 °C treatment. Additionally, percent germination was significantly lower for the seeds incubated in the saline solutions (100, 200, 400, and 600 mmol/L NaCl) and germinated under colder conditions (15/25 °C), compared with the seeds incubated in non-saline solutions (control group, 0 mmol/L NaCl) and germinated under warmer conditions (35/25 °C). The highest recovery percentage was recorded for seeds of the hyper-saline habitat incubated at 35/25 °C. Thus, seeds maintained their viability despite experiencing a range of saline conditions and were able to germinate upon the arrival of suitable conditions, which can be an adaptation to its saline arid desert habitat.

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The effect of temperature and humidity on development and longevity of Amblyomma triguttatum triguttatum (Acarina: Ixodidae)

Bulletin of Entomological Research ◽

10.1017/s0007485300051737 ◽

1992 ◽

Vol 82 (2) ◽

pp. 203-208 ◽

Cited By ~ 10

Author(s):

A.A. Guglielmone

Keyword(s):

Harsh Environments ◽

Oviposition Period ◽

Effect Of Temperature ◽

Rate Of Development ◽

Saturation Deficit ◽

High Saturation ◽

Temperature And Humidity ◽

Low Humidity ◽

Desert Habitat ◽

C 50

AbstractThe development and longevity of Amblyomma triguttatum triguttatum Koch were studied at temperatures of 15, 20, 25, 30, 35 and 40°C, and humidities with water staturation deficits of 2–3, 8–9 and 16–17 mm Hg. No stage developed at 40°C and the engorged larva was the only stage able to develop at 15°C. The rate of development was inversely related to temperature, with the exception of the pre-oviposition period of the engorged female which was longer at 35°C than at 30°C. The egg was the most vulnerable stage to high saturation deficit (low humidity) but some did survive in constant conditions of 16–17 mm Hg, showing an adaptation to harsh environments; A. t. triguttatum survives in a semi-desert habitat. The longevity of the unfed stages increased from the larvae, nymphs to adults. The longevity decreased with increase of temperature and decrease of humidity with the exception of adults maintained at 30°C and 16–17 mm Hg, which had a longer viability to the same saturation deficit at 20°C (50% mortality) and 25°C (50% and 100% mortality).

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Germination asynchrony is increased by dual seed bank presence in two desert perennial halophytes

Botany ◽

10.1139/cjb-2019-0071 ◽

2019 ◽

Vol 97 (11) ◽

pp. 639-649 ◽

Cited By ~ 1

Author(s):

Arvind Bhatt ◽

Narayana R. Bhat ◽

Flavio Lozano-Isla ◽

David Gallacher ◽

Andrea Santo ◽

...

Keyword(s):

Seed Bank ◽

Environmental Conditions ◽

Germination Rate ◽

Soil Surface ◽

Seed Banks ◽

Viable Seed ◽

Plant Recruitment ◽

Soil Seed Banks ◽

Desert Habitat

Maintaining a viable seed bank throughout the germination season is considered very important for plant recruitment in desert environments, where environmental conditions are unpredictable. Seeds from fully matured Seidlitzia rosmarinus Bunge ex Boiss and Halothamnus iraqensis Botsch. were collected in December 2016, then April, June, and September 2017 from both soil-surface and aerial seed banks. Both of the species were selected mainly by their capacity to rehabilitate saline coastal sites. Germination was analyzed under two photoperiods (0 or 12 h light per day), with winged or dewinged perianths. Seidlitzia rosmarinus had a shorter seasonal range in comparison with H. iraqensis (6 and 9 months, respectively), and the presence of a winged perianth reduced the germination rate of both species. A permanent winged perianth significantly inhibited the germination rate in both species. In the absence of perianth, the germination registered in December 2016 was mostly 100%, but declined to around 20% in September 2017. Seeds are thus more likely to germinate after scarification from wind mobilization, and do not require burial. Our results show that seeds of both the aerial and soil banks are transitory, and viable only during the winter months. Taken together, the combination of aerial and soil seed banks has greatly facilitated germination asynchrony in their environmentally unpredictable desert habitat.

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Effect of salinity, temperature, and growth regulators on the germination and early seedling growth of Atriplex griffithii var. stocksii

Canadian Journal of Botany ◽

10.1139/b94-063 ◽

1994 ◽

Vol 72 (4) ◽

pp. 475-479 ◽

Cited By ~ 89

Author(s):

M. Ajmal Khan ◽

Yasmeen Rizvi

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Growth Regulators ◽

High Concentration ◽

Early Seedling Growth ◽

Early Seedling ◽

Desert Habitat ◽

Temperature And Growth ◽

Alternating Temperature ◽

Saline Desert

Seed germination and early seedling growth of Atriplex griffithii var. stocksii from seeds collected from a saline desert habitat in Karachi, Pakistan, were studied. The seeds of A. griffithii did not germinate under high salt stress (516 mM NaCl). Best germination percentages were obtained in distilled water. Seed germination was stimulated in light at cooler alternating temperature (25:10 °C) and inhibited at warmer temperature (30:15, 30:20, and 35:25 °C) regimes. Early seedling growth showed responses towards salinity and temperature that were similar to the germination responses. Both GA3 and kinetin alleviated salinity-induced germination inhibition, and in most cases germination was stimulated by growth regulator treatments. A low concentration of kinetin (0.46 μM) and a high concentration of GA3 (28.9 μM) significantly promoted early seedling growth at all salinity treatments. Key words: Atriplex griffithii var. stocksii, seed germination, early seedling growth, salinity, temperature, growth regulators.

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