The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts （CHTs） were evaluated and compared with those of bushy hill forests. Soil sam...The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts （CHTs） were evaluated and compared with those of bushy hill forests. Soil samples were collected from three different depths （0-5 cm, 5-15 cm and 15-30 cm）, digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher （p≤ 0.05） in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes.展开更多
The bushy root-2(brt-2)tomato mutant has twisting roots,and slower plant development.Here we used whole genome resequencing and genetic mapping to show that brt-2 is caused by a serine to cysteine(S75C)substitution in...The bushy root-2(brt-2)tomato mutant has twisting roots,and slower plant development.Here we used whole genome resequencing and genetic mapping to show that brt-2 is caused by a serine to cysteine(S75C)substitution in the DNA binding domain(DBD)of a heat shock factor class B(HsfB)encoded by SolycHsfB4a.This gene is orthologous to the Arabidopsis SCHIZORIZA gene,also known as AtHsfB4.The brt-2 phenotype is very similar to Arabidopsis lines in which the function of AtHsfB4 is altered:a proliferation of lateral root cap and root meristematic tissues,and a tendency for lateral root cap cells to easily separate.The brt-2 S75C mutation is unusual because all other reported amino acid substitutions in the highly conserved DBD of eukaryotic heat shock factors are dominant negative mutations,but brt-2 is recessive.We further show through reciprocal grafting that brt-2 exerts its effects predominantly through the root genotype even through BRT-2 is expressed at similar levels in both root and shoot meristems.Since AtHsfB4 is induced by root knot nematodes(RKN),and loss-of-function mutants of this gene are resistant to RKNs,BRT-2 could be a target gene for RKN resistance,an important trait in tomato rootstock breeding.Gene&accession numbers SolycHsfB4a-Solyc04g078770.展开更多
For more than two decades acetolactate synthase (ALS) inhibiting herbicides have been the major weed control tools in winter wheat which resulted in selection of resistant weeds to those herbicides. Premix of pyrasulf...For more than two decades acetolactate synthase (ALS) inhibiting herbicides have been the major weed control tools in winter wheat which resulted in selection of resistant weeds to those herbicides. Premix of pyrasulfotole & bromoxynil (Huskie?), a relatively new herbicide, was registered for use in wheat in 2008. Pyrasulfotole inhibits 4-hydoxyphenylpyruvate dioxygenase (HPPD) enzyme in susceptible plants and is the first significant new mode of action for use in cereals for more than two decades. Field experiments were conducted from 2007 to 2010 at two locations in Kansas, USA to test the efficacy of pyrasulfotole & bromoxynil for broadleaf weed control and crop safety in winter wheat. Treatments included pyrasulfotole & bromoxynil alone at 253 g·ai·ha-1 and tank mixtures of pyrasulfotole & bromoxynil at 207 g·ai·ha-1 with MCPA at 280 g·ai·ha-1, dicamba at 140 g·ai·ha-1 or metsulfuron-methyl at 4.2 g·ai·ha-1. Herbicides were applied postemergence in fall and spring seasons. Pyrasulfotole & bromoxynil alone or in combination with tank-mix partners, regardless of application time, controlled flixweed, blue mustard, bushy wallflower and field pennycress 98% or more. Henbit control was better when pyrasulfotole & bromoxynil treatments were applied in fall than spring (≥98% vs ≥67%). Pyrasulfotole & bromoxynil alone applied in spring was not effective on wild buckwheat, but tank mixing with dicamba or metsulfuron-methyl controlled it 84% or more. Pyrasulfotole & bromoxynil alone or as tank mixture caused little (≤7%) or no injury to wheat and the injury did not influence wheat grain yields. Based on excellent control of broadleaf weeds evaluated, pyrasulfotole & bromoxynil is an alternative tool to control ALS-inhibitor resistant weeds in winter wheat. Fall season application and tank mixing with other herbicides are desirable for effective and broad spectrum weed control.展开更多
Based on Feng's theory of formal vector fields and formal flows, we study the convergence problem of the formal energies of symplectic methods for Hamiltonian systems and give the clear growth of the coefficients ...Based on Feng's theory of formal vector fields and formal flows, we study the convergence problem of the formal energies of symplectic methods for Hamiltonian systems and give the clear growth of the coefficients in the formal energies. With the help of B-series and Bernoulli functions, we prove that in the formal energy of the mid-point rule, the coefficient sequence of the merging products of an arbitrarily given rooted tree and the bushy trees of height 1(whose subtrees are vertices), approaches 0 as the number of branches goes to ∞; in the opposite direction, the coefficient sequence of the bushy trees of height m(m ≥ 2), whose subtrees are all tall trees, approaches ∞ at large speed as the number of branches goes to +∞. The conclusion extends successfully to the modified differential equations of other Runge-Kutta methods. This disproves a conjecture given by Tang et al.(2002), and implies:(1) in the inequality of estimate given by Benettin and Giorgilli(1994) for the terms of the modified formal vector fields, the high order of the upper bound is reached in numerous cases;(2) the formal energies/formal vector fields are nonconvergent in general case.展开更多
文摘The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts （CHTs） were evaluated and compared with those of bushy hill forests. Soil samples were collected from three different depths （0-5 cm, 5-15 cm and 15-30 cm）, digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher （p≤ 0.05） in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes.
基金The research was supported by BBSRC-UKRI fundingthe RootLINK(BB/L01954X/1)project focused on the“Understanding the Genetic Basis of Traits for Rootstock Improvement in Vegetable Crops”.
文摘The bushy root-2(brt-2)tomato mutant has twisting roots,and slower plant development.Here we used whole genome resequencing and genetic mapping to show that brt-2 is caused by a serine to cysteine(S75C)substitution in the DNA binding domain(DBD)of a heat shock factor class B(HsfB)encoded by SolycHsfB4a.This gene is orthologous to the Arabidopsis SCHIZORIZA gene,also known as AtHsfB4.The brt-2 phenotype is very similar to Arabidopsis lines in which the function of AtHsfB4 is altered:a proliferation of lateral root cap and root meristematic tissues,and a tendency for lateral root cap cells to easily separate.The brt-2 S75C mutation is unusual because all other reported amino acid substitutions in the highly conserved DBD of eukaryotic heat shock factors are dominant negative mutations,but brt-2 is recessive.We further show through reciprocal grafting that brt-2 exerts its effects predominantly through the root genotype even through BRT-2 is expressed at similar levels in both root and shoot meristems.Since AtHsfB4 is induced by root knot nematodes(RKN),and loss-of-function mutants of this gene are resistant to RKNs,BRT-2 could be a target gene for RKN resistance,an important trait in tomato rootstock breeding.Gene&accession numbers SolycHsfB4a-Solyc04g078770.
基金thank Bayer CropScience for their financial support to this projectContribution number 13-174-J from the Kansas Agricultural Experiment Station.
文摘For more than two decades acetolactate synthase (ALS) inhibiting herbicides have been the major weed control tools in winter wheat which resulted in selection of resistant weeds to those herbicides. Premix of pyrasulfotole & bromoxynil (Huskie?), a relatively new herbicide, was registered for use in wheat in 2008. Pyrasulfotole inhibits 4-hydoxyphenylpyruvate dioxygenase (HPPD) enzyme in susceptible plants and is the first significant new mode of action for use in cereals for more than two decades. Field experiments were conducted from 2007 to 2010 at two locations in Kansas, USA to test the efficacy of pyrasulfotole & bromoxynil for broadleaf weed control and crop safety in winter wheat. Treatments included pyrasulfotole & bromoxynil alone at 253 g·ai·ha-1 and tank mixtures of pyrasulfotole & bromoxynil at 207 g·ai·ha-1 with MCPA at 280 g·ai·ha-1, dicamba at 140 g·ai·ha-1 or metsulfuron-methyl at 4.2 g·ai·ha-1. Herbicides were applied postemergence in fall and spring seasons. Pyrasulfotole & bromoxynil alone or in combination with tank-mix partners, regardless of application time, controlled flixweed, blue mustard, bushy wallflower and field pennycress 98% or more. Henbit control was better when pyrasulfotole & bromoxynil treatments were applied in fall than spring (≥98% vs ≥67%). Pyrasulfotole & bromoxynil alone applied in spring was not effective on wild buckwheat, but tank mixing with dicamba or metsulfuron-methyl controlled it 84% or more. Pyrasulfotole & bromoxynil alone or as tank mixture caused little (≤7%) or no injury to wheat and the injury did not influence wheat grain yields. Based on excellent control of broadleaf weeds evaluated, pyrasulfotole & bromoxynil is an alternative tool to control ALS-inhibitor resistant weeds in winter wheat. Fall season application and tank mixing with other herbicides are desirable for effective and broad spectrum weed control.
基金supported by National Natural Science Foundation of China(Grant No.11371357)the Marine Public Welfare Project of China(Grant No.201105032)
文摘Based on Feng's theory of formal vector fields and formal flows, we study the convergence problem of the formal energies of symplectic methods for Hamiltonian systems and give the clear growth of the coefficients in the formal energies. With the help of B-series and Bernoulli functions, we prove that in the formal energy of the mid-point rule, the coefficient sequence of the merging products of an arbitrarily given rooted tree and the bushy trees of height 1(whose subtrees are vertices), approaches 0 as the number of branches goes to ∞; in the opposite direction, the coefficient sequence of the bushy trees of height m(m ≥ 2), whose subtrees are all tall trees, approaches ∞ at large speed as the number of branches goes to +∞. The conclusion extends successfully to the modified differential equations of other Runge-Kutta methods. This disproves a conjecture given by Tang et al.(2002), and implies:(1) in the inequality of estimate given by Benettin and Giorgilli(1994) for the terms of the modified formal vector fields, the high order of the upper bound is reached in numerous cases;(2) the formal energies/formal vector fields are nonconvergent in general case.
