תפריט נגישות
ניגודיות עדינהניגודיות גבוהה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם תפריט נגישותניגודיות עדינהניגודיות גבוההמונוכרוםהדגשת קישוריםחסימת אנימציהפונט קריאסגוראיפוס הגדרות נגישותלהורדת מודול נגישות חינםCharles L. Guy
Many plants of tropical and subtropical origin, including a large number of economically important crops, such as tomato, rice, cotton, cucumber and maize, are severely damaged when exposed to temperatures between 2 and 15°C (chilling temperatures). The symptoms of these chilling injuries include cessation of growth, wilting, chlorosis, and necrosis. In contrast with chilling-sensitive species, the cruciferous plant Arabidopsis thaliana is chilling tolerant, and is able to grow to maturity even at a low temperature of 4°C. Therefore, at the genetic level, Arabidopsis may provide a useful model plant system for the identification of chilling-tolerance traits. Taking a mutational approach several ethyl methanesulphonate (EMS) and T-DNA insertion chilling-sensitive mutants have been identified that show wild-type phenotypes when grown at normal temperatures, but are severely damaged following transfer to low temperatures. These mutants provide valuable genetic sources for the identification of structural or regulatory genes that are crucial for plant survival at chilling temperatures. Furthermore, it has been reported that a number of mutations at several genetic loci involved in fatty acid biosynthesis (fab1) and fatty acid desaturation (fad2, fad5 and fad6) resulted in reduced-growth and chlorosis phenotypes at low temperatures, thus providing direct evidence for the contribution of lipid polyunsaturation to low-temperature fitness. Arabidopsis has also proven to be an efficient model system for the identification of major biochemical mechanisms involved in protection of the photosynthesis system from photooxidative damage following exposure to excess light energy at low temperatures. DNA microarray studies have revealed new insights into the complex network of transcriptional regulation at low temperatures and the possible interrelationships between cold-regulated gene expression and acquisition of chilling tolerance but this work is just beginning. At last, recently, Arabidopsis is also being used as a main model plant system to study possible genetic linkages between the programmed cell death (PCD) mechanism and development of necrotic lesions following exposure to biotic and abiotic stresses, including chilling. Overall, it is concluded that Arabidopsis can potentially be an ideal model system for basic studies on chilling stress and for identification of key components of chilling-tolerance traits in plants.
Charles L. Guy
Many plants of tropical and subtropical origin, including a large number of economically important crops, such as tomato, rice, cotton, cucumber and maize, are severely damaged when exposed to temperatures between 2 and 15°C (chilling temperatures). The symptoms of these chilling injuries include cessation of growth, wilting, chlorosis, and necrosis. In contrast with chilling-sensitive species, the cruciferous plant Arabidopsis thaliana is chilling tolerant, and is able to grow to maturity even at a low temperature of 4°C. Therefore, at the genetic level, Arabidopsis may provide a useful model plant system for the identification of chilling-tolerance traits. Taking a mutational approach several ethyl methanesulphonate (EMS) and T-DNA insertion chilling-sensitive mutants have been identified that show wild-type phenotypes when grown at normal temperatures, but are severely damaged following transfer to low temperatures. These mutants provide valuable genetic sources for the identification of structural or regulatory genes that are crucial for plant survival at chilling temperatures. Furthermore, it has been reported that a number of mutations at several genetic loci involved in fatty acid biosynthesis (fab1) and fatty acid desaturation (fad2, fad5 and fad6) resulted in reduced-growth and chlorosis phenotypes at low temperatures, thus providing direct evidence for the contribution of lipid polyunsaturation to low-temperature fitness. Arabidopsis has also proven to be an efficient model system for the identification of major biochemical mechanisms involved in protection of the photosynthesis system from photooxidative damage following exposure to excess light energy at low temperatures. DNA microarray studies have revealed new insights into the complex network of transcriptional regulation at low temperatures and the possible interrelationships between cold-regulated gene expression and acquisition of chilling tolerance but this work is just beginning. At last, recently, Arabidopsis is also being used as a main model plant system to study possible genetic linkages between the programmed cell death (PCD) mechanism and development of necrotic lesions following exposure to biotic and abiotic stresses, including chilling. Overall, it is concluded that Arabidopsis can potentially be an ideal model system for basic studies on chilling stress and for identification of key components of chilling-tolerance traits in plants.
