نتایج جستجو برای: element boron

تعداد نتایج: 221337  

2017
Akira Yoshinari Junpei Takano

Boron is an essential element for plants but is toxic in excess. Therefore, plants must adapt to both limiting and excess boron conditions for normal growth. Boron transport in plants is primarily based on three transport mechanisms across the plasma membrane: passive diffusion of boric acid, facilitated diffusion of boric acid via channels, and export of borate anion via transporters. Under bo...

Journal: :Environmental Health Perspectives 1994
D G Blevins K M Lukaszewski

Boron has been recognized since 1923 as an essential micronutrient element for higher plants. Over the years, many roles for boron in plants have been proposed, including functions in sugar transport, cell wall synthesis and lignification, cell wall structure, carbohydrate metabolism, RNA metabolism, respiration, indole acetic acid metabolism, phenol metabolism and membrane transport. However, ...

2015
Shigeki Kawai Shohei Saito Shinichiro Osumi Shigehiro Yamaguchi Adam S. Foster Peter Spijker Ernst Meyer

Boron is a unique element in terms of electron deficiency and Lewis acidity. Incorporation of boron atoms into an aromatic carbon framework offers a wide variety of functionality. However, the intrinsic instability of organoboron compounds against moisture and oxygen has delayed the development. Here, we present boron-doped graphene nanoribbons (B-GNRs) of widths of N=7, 14 and 21 by on-surface...

2004
CAROLINE COX

Boric acid and its chemical relatives are pesticides that are derived from the element boron. Boron rarely occurs alone and is typically found in combination with other elements; common combinations are boric acid or borates.1 Unlike many pesticides which are synthetic compounds,2 boric acid and related pesticides are naturally occurring compounds.1 Boron compounds are widely found in rivers, s...

2008
C. BUSTOS - OBREGON

Boron is a chemical element widely used in many industrial activities. Exposure to it affects many organs in mammals, mainly reproductive male organs. This work evaluates boron effect in testis. For this purpose, 12mg Boron/L of drinking water, equivalent to Arica tap water, was given for 42 days to 85 days old CF1 male mice (experimental group). Another group (control group) drunk tap water of...

2000
Duli Zhao Derrick M. Oosterhuis

In crop growth and development, boron (B) is an essential trace element. Boron deficiency is common in highly leached, acidic sandy soils of cotton (Gossypium hirsutum L.) growing regions in the world. Boron is particularly important in pollen germination and pollen tube growth resulting in successful fruit setting. Therefore, B deficiency during flowering and fruiting may significantly reduce ...

2011
Howard W. Fisher

Boron is the fifth element in the periodic table of elements and has a number of important functions. The borate minerals have been known for thousands of years and have varied history from the deserts of Tibet to the alchemists of the middle ages. Boron occurs in most foods produced from plants. Since 1989 its nutritional value has been debated. Boron plays several biochemical roles in animals...

Journal: :Accounts of chemical research 2014
Alina P Sergeeva Ivan A Popov Zachary A Piazza Wei-Li Li Constantin Romanescu Lai-Sheng Wang Alexander I Boldyrev

Boron is an interesting element with unusual polymorphism. While three-dimensional (3D) structural motifs are prevalent in bulk boron, atomic boron clusters are found to have planar or quasi-planar structures, stabilized by localized two-center-two-electron (2c-2e) σ bonds on the periphery and delocalized multicenter-two-electron (nc-2e) bonds in both σ and π frameworks. Electron delocalization...

Jamal Davoodi, Nader Malih, Soghra Mohammadzadeh

Over the past years, two-dimensional materials such as graphene, phosphorene, silicene, and boron-nitride have attracted the attention of many researchers. After the successful synthesis of graphene, due to its many new applications, researches began to produce nanosheets from other elements, and among these elements, boron was one of the options. In the periodic table of elements, boron is ahe...

Journal: :Plant physiology 1968
J M Dear S Aronoff

It is generally assumed in plant nutrition that an essential element is essential for all plants, though the amounts required may be appreciably different. Thus, the need for boron is shown within 3 to 4 days by the necrosis of sunflower, tomato, or tobacco tissue, but requires at least 3 weeks in soybeans. The suggestion (3) that boron was required for differentiation rather than cell division...

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