High-affinity K؉ uptake in plant roots is rapidly up-regulated when K ؉ is withheld and down-regulated when K ؉ is resupplied. These processes make important contributions to plant K ؉ homeostasis. A cDNA coding for a high-affinity K ؉ transporter, HKT1, was earlier cloned from wheat (Triticum aestivum L.) roots and functionally characterized. We demonstrate here that in both barley (Hordeum vulgare L.) and wheat roots, a rapid and large upregulation of HKT1 mRNA levels resulted when K ؉ was withdrawn from growth media. This effect was specific for K ؉ ; withholding N caused a modest reduction of HKT1 mRNA levels. Up-regulation of HKT1 transcript levels in barley roots occurred within 4 h of removing K ؉ , which corresponds to the documented increase of high-affinity K ؉ uptake in roots following removal of K ؉ . Increased expression of HKT1 mRNA was evident before a decline in total root K ؉ concentration could be detected. Resupply of 1 mM K ؉ was sufficient to strongly reduce HKT1 transcript levels. In wheat root cortical cells, both membrane depolarizations in response to 100 M K ؉ , Cs ؉ , and Rb ؉ , and high-affinity K ؉ uptake were enhanced by K ؉ deprivation. Thus, in both plant systems the observed physiological changes associated with manipulating external K ؉ supply were correlated with levels of HKT1 mRNA expression. Implications of these findings for K ؉ sensing and regulation of the HKT1 mRNA levels in plant roots are discussed.

The present study investigated impact of energy and economy related variables on CO2 emissions in 49 countries of belt and road initiative from 1995–2018. The robust type of cross-section dependence and heterogeneity methods were adopted to analyze data set of countries. Energy consumption, foreign direct investment, medium and high-tech industry, and GDP has been found highly unfavorable for the ecological health (CO2 emissions) in 49 nations on BRI panel. However, renewable energy consumption has been found in positive correlation with environmental quality (CO2). Financial development indicator has no significant impact on CO2 emissions in present study. The present outcomes clearly claim strong relationship of economic growth and energy with increased CO2 emissions in 49 nations. Therefore, it is important for policy makers, experts and governments to incentivize and appreciate portfolio investors for sustainable green investments to transform the economic growth into a sustainable and energy efficient development.

Based on the main physical processes, we deduce the relationships among the incident energy 𝑊p0 of the primary electron, the number of released secondary electrons (𝑖.𝑒. 𝛿 PE𝜃 ) per primary electron entering the metal at incident angle 𝜃 and the angle 𝜃 itself. In addition, the relationship of 𝛿 PE𝜃 at 𝜃 = 0 ∘ , i.e. 𝛿PE0, with 𝑊p0 is determined. From the experimental results, the relationship of the ratio at 𝜃 = 0 ∘ , i.e. 𝛽 0 which is the ratio of the average number of released secondary electrons generated by a single primary electron backscattered at the metal surface to that generated by a single primary electron entering the metal, with 𝑊p0 is determined. Moreover, the relationships among the ratio 𝛽 𝜃 , 𝑊p0 and 𝜃 are obtained. Based on the relationships among the secondary electron yield at 𝜃 (i.e. 𝛿 𝜃 ), the yield at 𝜃 = 0 ∘ (i.e. 𝛿 0 ), the backscattering coefficient at 𝜃 (i.e. 𝜂 𝜃 ), the coefficient at 𝜃 = 0 ∘ (i.e. 𝜂 0 ), 𝛿 PE𝜃 and 𝛿PE0, we deduce the universal formula for 𝛿 𝜃 , 𝛿 0 , 𝜂 𝜃 , 𝜂 0 , and 𝑊p0 for the primary electrons at an incident energy of 2-10 keV. The secondary electron yields calculated from the universal formula and the experimental yields of some metals are compared, and the results suggest that the proposed formula is universal for estimation of secondary electron yields at 𝜃 = 0 ∘ − 80 ∘ .

Based on the main physical processes of secondary electron emission from metals, the relation that the product of the number of secondary electron released per primary electron at high incident electron energy and the (n-1)th power of incident energy of primary electron is equal to constant C was deduced, where n is the energy exponent, based on the relation between the number of secondary electron released per primary electron at high incident electron energy and secondary electron yield. The relation that the product of the secondary electron yield at high incident electron energy and the (n-1)th power of incident energy of primary electron is equal to constant D was deduced. The constant D and the energy exponent n of the primary electron in the energy range 10 to 100 keV hitting on gold and aluminum are computed with the ESTAR program and experimental results in scanning electron microscope (SEM), respectively, therefore, the formulas for the incident energy dependence of secondary electron yield in the energy range 10 to 100 keV from gold and aluminum were deduced. The formulas were proved to be true by experimental results in SEM. The results were discussed and a conclusion was drawn. The formulas from gold and aluminum were successfully deduced.

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