Mango which is also known as the king of fruits in the country is the second largest growing fruit after citrus in Pakistan. Although mango is being grown in more than hundred countries none of them is comparable to P...Mango which is also known as the king of fruits in the country is the second largest growing fruit after citrus in Pakistan. Although mango is being grown in more than hundred countries none of them is comparable to Pakistani mango which is famous for its unique taste all over the world. Pakistan＇s per hectare production is much lower than its potential. The purpose of this study was to assess those factors which are preventing mango growers from getting its potential yield. For this major mango producing area, Muzzaffargarh was selected. The 110 randomly selected farmers were interviewed with a well-designed questionnaire. The mango growers were divided into three categories on the basis of landholding. The Cobb-Douglas model was used to assess the effect of different factors on the productivity. The education level and age of large farmers was found highest among small and medium farmers. Large farmers were enjoying significant high profit per acre with US$519.58 as compared to medium farmers （US$454.15） and small farmers （US$395.10）. The independent variables were explaining almost 89 percent variation in productivity of mango. The significant positive effect of orchard experience, access to extension services, the quantity of NPK, quantity of pesticides and labour cost was found. The age and intercropping practices in mango orchard had a significant negative effect on mango production. Credit facilities must be made available at lower interest rate and the range of extension services must be enhanced to increase the productivity of mango.展开更多
Terpenoids are the largest and most diverse class of plant-specialized metabolites, which function in diverse physiological processes during plant development. In the biosynthesis of plant terpenoids, short-chain pren...Terpenoids are the largest and most diverse class of plant-specialized metabolites, which function in diverse physiological processes during plant development. In the biosynthesis of plant terpenoids, short-chain prenyltransferases （SC-PTs）, together with terpene synthases （TPSs）, play critical roles in determining terpenoid diversity. SC-PTs biosynthesize prenyl pyrophosphates with different chain lengths, and these compounds are the direct precursors of terpenoids. Arabidopsis thaliana possesses a subgroup of SC-PTs whose functions are not clearly known. In this study, we focus on 10 geranylgeranyl pyro- phosphate synthase-like [GGPPSL] proteins, which are commonly thought to produce GGPP [C20]. We found that a subset of members of the Arabidopsis GGPPSL gene family have undergone neo- functionalization： GGPPSL6, 7, 9, and 10 mainly have geranylfarnesyl pyrophosphate synthase activity （C25; renamed AtGFPPS1, 2, 3, and 4）, and GGPPSL8 produces even longer chain prenyl pyrophosphate （〉C30; renamed polyprenyl pyrophosphate synthase 2, AtPPPS2）. By solving the crystal structures of AtGFPPS2, AtPPPS2, and AtGGPPS11, we reveal the product chain-length determination mechanism of SC-PTs and interpret it as a ＂three floors＂ model. Using this model, we identified a novel GFPPS clade distributed in Brassicaceae plants and found that the GFPPS gene typically occurs in tandem with a gene encoding a TPS, forming a GFPPS-TPS gene cluster.展开更多
文摘Mango which is also known as the king of fruits in the country is the second largest growing fruit after citrus in Pakistan. Although mango is being grown in more than hundred countries none of them is comparable to Pakistani mango which is famous for its unique taste all over the world. Pakistan＇s per hectare production is much lower than its potential. The purpose of this study was to assess those factors which are preventing mango growers from getting its potential yield. For this major mango producing area, Muzzaffargarh was selected. The 110 randomly selected farmers were interviewed with a well-designed questionnaire. The mango growers were divided into three categories on the basis of landholding. The Cobb-Douglas model was used to assess the effect of different factors on the productivity. The education level and age of large farmers was found highest among small and medium farmers. Large farmers were enjoying significant high profit per acre with US$519.58 as compared to medium farmers （US$454.15） and small farmers （US$395.10）. The independent variables were explaining almost 89 percent variation in productivity of mango. The significant positive effect of orchard experience, access to extension services, the quantity of NPK, quantity of pesticides and labour cost was found. The age and intercropping practices in mango orchard had a significant negative effect on mango production. Credit facilities must be made available at lower interest rate and the range of extension services must be enhanced to increase the productivity of mango.
文摘Terpenoids are the largest and most diverse class of plant-specialized metabolites, which function in diverse physiological processes during plant development. In the biosynthesis of plant terpenoids, short-chain prenyltransferases （SC-PTs）, together with terpene synthases （TPSs）, play critical roles in determining terpenoid diversity. SC-PTs biosynthesize prenyl pyrophosphates with different chain lengths, and these compounds are the direct precursors of terpenoids. Arabidopsis thaliana possesses a subgroup of SC-PTs whose functions are not clearly known. In this study, we focus on 10 geranylgeranyl pyro- phosphate synthase-like [GGPPSL] proteins, which are commonly thought to produce GGPP [C20]. We found that a subset of members of the Arabidopsis GGPPSL gene family have undergone neo- functionalization： GGPPSL6, 7, 9, and 10 mainly have geranylfarnesyl pyrophosphate synthase activity （C25; renamed AtGFPPS1, 2, 3, and 4）, and GGPPSL8 produces even longer chain prenyl pyrophosphate （〉C30; renamed polyprenyl pyrophosphate synthase 2, AtPPPS2）. By solving the crystal structures of AtGFPPS2, AtPPPS2, and AtGGPPS11, we reveal the product chain-length determination mechanism of SC-PTs and interpret it as a ＂three floors＂ model. Using this model, we identified a novel GFPPS clade distributed in Brassicaceae plants and found that the GFPPS gene typically occurs in tandem with a gene encoding a TPS, forming a GFPPS-TPS gene cluster.
