Soil water content significantly influenced uptake and distribution of ^15N in both Newhall and Yamasitaka. The content of ^15N uptake in treated plants was less than that in controlled plants, under 20% soil water co...Soil water content significantly influenced uptake and distribution of ^15N in both Newhall and Yamasitaka. The content of ^15N uptake in treated plants was less than that in controlled plants, under 20% soil water content, ^15N was only taken up 16.02% by Newhall and 10.11% by Yamasitaka. The most ^15N was detained in root and old shoots under water stress. Protein concentration in two cultivars significantly decreased by water deficit stress, protein content of Newhall and Yamasitaka in controlled plants was 16.29 mg/g fresh weight and 15.89 mg/g fresh weight, but at 20% of water content, these were 9.60 mg/g fresh weight and 9.02 mg/g fresh weight. Water stress increased concentration of NH3-NH4^＋, Arginine and Proline. Compared with control plants, concentrations of NH3-NH4^＋ in both Newhall and Yamasitaka at 20% water content treatment increased 5.83 fold and 5.71 fold, Arginine increased 197% and 205%, and Proline increased 112% and 132%.展开更多
The objectives of this investigation are to study nitrogen uptake,translocation,accumulation and distribution in mango tree organs using labeled nitrogen(^(15)N)and to understand the mechanism of boron action in incre...The objectives of this investigation are to study nitrogen uptake,translocation,accumulation and distribution in mango tree organs using labeled nitrogen(^(15)N)and to understand the mechanism of boron action in increasing fruit yield in the off-year.A field experiment was conducted using fifteen-year-old mango trees(cv.Zebda)grown at Al Malak Valley Farm,El-Sharkeya Governorate-Egypt.Treatments included the application of(^(15)NH4)2SO4,“in the on-year”,at a rate of 50 g nitrogen/tree through the stem injection technique.While boron was sprayed on the same trees“in the off-year”at the following rates:0.0(control),250 and 500 mg·L^(-1).The authors hypothesize that boron and nitrogen act synergistically to increase mango fruit yield in the off-year.Results indicated that the highest ^(15)N uptake and accumulation in the on and off-years was observed in the upper(young leaves).When boron was applied at 250 mg·L^(-1),in the off-year,the upper(young leaves)recorded the highest ^(15)N uptake and accumulation(%^(15)Ndff=13.93)relative to the other two leaf categories and those of the on-year.In the on-year fruit accumulated higher ^(15)N than leaf or bud.In the off-year,bud exhibited the highest ^(15)N accumulation without boron application,while leaves exhibited the highest ^(15)N with boron application.The highest%^(15)Ndff in all tree organs was observed at 250 mg·L^(-1) boron rate.Boron increased nitrogen uptake,translocation and accumulation in mango tree organs.A synergistic relationship was observed between boron and nitrogen which led to an increase in fruit yield in the off-year.展开更多
基金Acknowledgment The authors acknowledge the financial support of the CARS-3 （China Agricultural Research System） and National Natural Science Foundation of China （31071763） and suggestions of Dr. C.J. Lovatt,Professor of Plant Physiology, University of California, Riverside.
文摘Soil water content significantly influenced uptake and distribution of ^15N in both Newhall and Yamasitaka. The content of ^15N uptake in treated plants was less than that in controlled plants, under 20% soil water content, ^15N was only taken up 16.02% by Newhall and 10.11% by Yamasitaka. The most ^15N was detained in root and old shoots under water stress. Protein concentration in two cultivars significantly decreased by water deficit stress, protein content of Newhall and Yamasitaka in controlled plants was 16.29 mg/g fresh weight and 15.89 mg/g fresh weight, but at 20% of water content, these were 9.60 mg/g fresh weight and 9.02 mg/g fresh weight. Water stress increased concentration of NH3-NH4^＋, Arginine and Proline. Compared with control plants, concentrations of NH3-NH4^＋ in both Newhall and Yamasitaka at 20% water content treatment increased 5.83 fold and 5.71 fold, Arginine increased 197% and 205%, and Proline increased 112% and 132%.
文摘The objectives of this investigation are to study nitrogen uptake,translocation,accumulation and distribution in mango tree organs using labeled nitrogen(^(15)N)and to understand the mechanism of boron action in increasing fruit yield in the off-year.A field experiment was conducted using fifteen-year-old mango trees(cv.Zebda)grown at Al Malak Valley Farm,El-Sharkeya Governorate-Egypt.Treatments included the application of(^(15)NH4)2SO4,“in the on-year”,at a rate of 50 g nitrogen/tree through the stem injection technique.While boron was sprayed on the same trees“in the off-year”at the following rates:0.0(control),250 and 500 mg·L^(-1).The authors hypothesize that boron and nitrogen act synergistically to increase mango fruit yield in the off-year.Results indicated that the highest ^(15)N uptake and accumulation in the on and off-years was observed in the upper(young leaves).When boron was applied at 250 mg·L^(-1),in the off-year,the upper(young leaves)recorded the highest ^(15)N uptake and accumulation(%^(15)Ndff=13.93)relative to the other two leaf categories and those of the on-year.In the on-year fruit accumulated higher ^(15)N than leaf or bud.In the off-year,bud exhibited the highest ^(15)N accumulation without boron application,while leaves exhibited the highest ^(15)N with boron application.The highest%^(15)Ndff in all tree organs was observed at 250 mg·L^(-1) boron rate.Boron increased nitrogen uptake,translocation and accumulation in mango tree organs.A synergistic relationship was observed between boron and nitrogen which led to an increase in fruit yield in the off-year.
