Insects may survive subzero temperatures by two general strategies: Freeze-tolerant insects withstand the formation of internal ice, while freeze-avoiding insects die upon freezing. While it is widely recognized that these represent alternative strategies to survive low temperatures, and mechanistic understanding of the physical and molecular process of cold tolerance are becoming well elucidat...

Recent progress in the characterization of two groups of genes responsible for natural differences in frost tolerance inwheat and barley is reviewed here. The first group includes the vernalization genes that delay flowering until the end of the winter and protect sensitive floral primordia. This process is regulated mainly by differences in the regulatory regions of VRN1 and VRN3 genes or in t...

to cope with cold stress, winter cereals regulate their development through adaptive mechanisms such as vernalization requirement. eight wheat and four barley cultivars were planted to determine the relationship between vernalization fulfilment and expression of cold tolerance under both field and controlled conditions. cultivars were planted at maragheh and karaj agricultural research stations...

OBJECTIVE The aim of this study was to test whether acupuncture could modify the threshold of tolerance to thermal and electrical stimuli. METHODS A randomised placebo-controlled single-blind trial was conducted in 36 healthy volunteers randomly distributed to control (no treatment), conventional acupuncture and sham acupuncture groups. The subjects were blind to the group allocation. The aut...

Alfalfa (Medicago sativa L.) is an important perennial forage, with high nutritional value, which is widely grown in the world. Because of low freezing tolerance, its distribution and production are threatened and limited by winter weather. To understand the complex regulation mechanisms of freezing tolerance in alfalfa, we performed transcriptome sequencing analysis under cold (4 °C) and freez...

In winter wheat (Triticum spp.) and barley (Hordeum vulgare) varieties, long exposures to nonfreezing cold temperatures accelerate flowering time (vernalization) and improve freezing tolerance (cold acclimation). However, when plants initiate their reproductive development, freezing tolerance decreases, suggesting a connection between the two processes. To better understand this connection, we ...

Most insects have the ability to alter their cold tolerance in response to temporal temperature fluctuations, and recent studies have shown that insect cold tolerance is closely tied to the ability to maintain transmembrane ion gradients that are important for the maintenance of cell membrane potential (Vm). Several studies have therefore suggested a link between preservation of Vm and cellular...

this study was conducted on two canola (brassica napus) cultivars, okapi a winter type and cold tolerant and rgs003 a spring type and cold sensitive. seedlings were grown in an environmentally controlled growth room with 16 h d-1 photoperiod at 22/16 °c (day/night, control). at the 4-leaf stage, half of pots were transferred to a cold growth room for 7 d at 10/3°c (day/night, cold treatment) an...

Due to its intrinsically interesting nature and importance to agriculture, considerable effort has been directed at understanding the phenomenon of “cold acclimation,” the process whereby certain plants increase in freezing tolerance upon exposure to low temperature. By 1980, thousands of research articles had been published on the topic and significant insights had been gained, including the f...