农学类英文文献.ppt

Salicylic acid and methyl jasmonate improve chilling tolerance in cold stored lemon fruit Journal of Plant Physiology (IF:2.77) author Xolani Irvin Sibozaa * Isa bertling  Content Introduction Z Experimental Materials and Methods Results and Analysis Discussion and Conclusion  1、 Introduction 1.1 Background Chilling injury(ci), a physiological disorder disrupting normal cell metabolism, is one of the most significant contributors to postharvest losses in citrus fruit (Sala32005 In citrus fruit, cI is manifested as pitting, rind staining red blotches and necrosis on the flavedo sala, 1999) Citrus fruit contain antioxidants such as phenolic compounds, that can mitigate cellular damage under chilling stress ( Grace, 2000)  Phenylalanine ammonia-lyase(PAL) is the key enzyme at the entrypoint of the phenyl propanoid pathway which is involved in defense and acclimation against chilling(rivero, 2001).The induction of Pal activity in response to stress has been considered a defense mechanism of fruit to withstand stress(Lafuente, 1997), therefore chilling can affect PAL activity levels (Ballesta, 2000)  Tomas-Barberan(2001)reported that POD and PPo are nvolved in the oxidation of antioxidants the enzymes POD and PPo have been associated with tissue browning during plant stress(Martinez-Tellez 1997) thereby decreasing the antioxidant status of the fruit Phenolic compounds are plant secondary metabolites involved in fruit quality (Tomas-Barberan, 2001). These compounds are powerful antioxidants(Grace, 2000) capable of scavenging reactive oxygen species (Gonzalez-Aguilar, 2004). However, their physiological functions have not been completely elucidated (Raimbaultet. 2011).  The beneficial effect of plant hormones such as methyl jasmonate(M])and salicylic acid (sA)in alleviating Cl has been demonstrated in zucchini squash(Wang and Buta, 1994), avocado, grapefruit, bell pepper( Meir et al 1996)and tomatoes(Ding et al. 2002) of MJ