Successful adaptation of a plant species is dependent upon the programming of critical growth stages so that the plant can capitalize on favorable weather periods during the growing season (Dominique and Andrew, 2010). Plants have evolved a variety of adaptive mechanisms that allow them to optimize growth and development while coping with environmental stresses. These mechanisms include seed and bud dormancy, photoperiod sensitivity, and low-temperature response and others (Fowler et al., 1999;Caius, 2010;Clint and Malcolm, 2007). Seed dormancy delays germination until after the embryo has gone through an after-ripening period. The overwinter survival of buds of many temperate zone trees and shrubs is dependent on a dormancy stage that starts in the late summer or early fall and ends after exposure to an extended period of cold or increasing day length in the spring. In addition to trees, many other dicots and grasses have a photoperiod response that can advance or delay flowering. Vernalization is a requirement for growth at low temperatures before a plant will flower. Most winter annual and biennial plants have a vernalization requirement. Low-temperature acclimation is an ability of plants to cold acclimate when exposed to gradually decreasing temperatures below a specific threshold. This is the most common mechanism that plants have evolved for adapting to low-temperature stress and examples of plants with the capacity to cold harden can be found in most species (Fowler et al., 1999;Nilson and Assmann, 2007;von Caemmerer and Baker, 2007;David and Jacqueline, 2010 AbstractIn the past few years, the signal transduction of the plant hormone abscisic acid (ABA) has been studied extensively and has revealed an unanticipated complex. ABA, characterized as an intracellular messenger, has been proven to act a critical function at the heart of a signaling network operation. It has been found that ABA plays an important role in improving plant tolerance to cold, as well as triggering leaf senescence for years. In addition, there have been many reports suggesting that the signaling pathways for leaf senescence and plant defense responses may overlap. Therefore, the objective was to review what is known about the involvement of ABA signaling in plant responses to cold stress and regulation of leaf senescence. An overview about how ABA is integrated into sugars and reactive oxygen species signaling pathways, to regulate plant cold tolerance and leaf senescence, is provided. These roles can provide important implications for biotechnologically improving plant cold tolerance.

No abstract

Coalbed gas extraction is an important means of exploiting and utilizing gas resources, as well as a means of preventing coal mine disasters. In view of the low gas extraction rate from coalbeds with high gas content and low permeability, a method of improving permeability through deep-hole cumulative blasting is applied to develop initial directional fractures using a jet flow. Under the action of the blasting stress wave and detonation gas wedge, the fractures extend over a large range within the coal, thereby improving coalbed permeability. This study focuses on the criteria of cumulative blasting-induced coalbed fracturing based on a literature review of the penetration effect of cumulative blasting. On this basis, we summarize the coal fracturing zone, crack extension process, and the key technologies of charging and hole sealing for cumulative blasting. In addition, the latest research progress in the optimization of field test drilling and blasting parameters for cumulative blasting is introduced. Research findings indicate that the permeability improvement mechanism of cumulative blasting could be further enhanced, and the technology and technical equipment are in urgent need of improvement. Finally, development trends in the cumulative blasting permeability improvement technique are identified.

No abstract

No abstract

No abstract

No abstract

No abstract