Relationships of water stress and abscisic acid on photosynthesis of soybean and sunflower leaves

Soybean (Glycine max (L.) Merr. \u27Amsoy 71\u27) and sunflower (Helianthus annuus L. \u27S-1888\u27) were grown in the greenhouse and growth chamber. The effects of water stress, endogenous and exogenous abscisic acid (ABA) on photosynthesis and related parameters were investigated. Water stress was imposed on soybean and sunflower growing in the same pot in growth chamber by withholding water. In addition, an improved method for ABA analysis by HPLC and GCMS system was developed in this study;Water stress affected on photosynthetic rate and its related parameters. Drastic decreases of leaf water potential, transpiration rate, and photosynthetic rate occurred as water stress developed, and these decreases were accompanied by sharp increases of leaf stomatal resistance and leaf temperature. After rewatering, leaf water potential, transpiration rate and CER increased with decreased stomatal resistance and leaf temperature. CER recovery was slower than that of water potential. Sunflower showed a consistently greater CER than that of soybean both during water stress period and the rewatering period. The difference in CER was apparently due to consistently lower stomatal resistance for sunflower along with lower leaf temperature as well as higher transpiration rate;Leaf endogenous ABA in response to water stress showed a different pattern between soybean and sunflower. ABA increased dramatically as desiccation continued for both species, and was 3.2 fold higher in soybean than that in sunflower under severe water stressed conditions when water potentials were less than -15 bars. The greater ABA content in soybean was associated with a greater stomatal resistance, a lower transpiration rate, and a lower CER. Exogenously applied ABA showed effects similar to that of endogenous ABA. It is clear that the difference in photosynthesis between soybean and sunflower was largely due to the differences in ABA contents, at least under water stressed condition;The procedures developed in this study provided a relatively quick, simple, efficient, and reliable method for extraction, purification and quantification of ABA from highly pigmented green tissues, such as soybean and sunflower leaves

Sufficient and necessary conditions of stochastic permanence and extinction for stochastic logistic populations under regime switching

In this paper, we prove that a stochastic logistic population under regime switching controlled by a Markov chain is either stochastically permanent or extinctive, and we obtain the sufficient and necessary conditions for stochastic permanence and extinction under some assumptions. In the case of stochastic permanence we estimate the limit of the average in time of the sample path of the solution by two constants related to the stationary probability distribution of the Markov chain and the parameters of the subsystems of the population model. Finally, we illustrate our conclusions through two examples

Assessing the effect of lens mass model in cosmological application with updated galaxy-scale strong gravitational lensing sample

By comparing the dynamical and lensing masses of early-type lens galaxies, one can constrain both the cosmological parameters and the density profiles of galaxies. We explore the constraining power on cosmological parameters and the effect of the lens mass model in this method with 161 galaxy-scale strong lensing systems, which is currently the largest sample with both high resolution imaging and stellar dynamical data. We assume a power-law mass model for the lenses, and consider three different parameterizations for $\gamma$ (i.e., the slope of the total mass density profile) to include the effect of the dependence of $\gamma$ on redshift and surface mass density. When treating $\delta$ (i.e., the slope of the luminosity density profile) as a universal parameter for all lens galaxies, we find the limits on the cosmological parameter $\Omega_m$ are quite weak and biased, and also heavily dependent on the lens mass model in the scenarios of parameterizing $\gamma$ with three different forms. When treating $\delta$ as an observable for each lens, the unbiased estimate of $\Omega_m$ can be obtained only in the scenario of including the dependence of $\gamma$ on both the redshift and the surface mass density, that is $\Omega_m = 0.381^{+0.185}_{-0.154}$ at 68\% confidence level in the framework of a flat $\Lambda$CDM model. We conclude that the significant dependencies of $\gamma$ on both the redshift and the surface mass density, as well as the intrinsic scatter of $\delta$ among the lenses, need to be properly taken into account in this method.Comment: Accepted for publication in MNRAS; 17 pages, 5 figures, 2 table

Mo Yan’s \u3cem\u3eRadish\u3c/em\u3e: Between the Real and the Surreal

In their article “Mo Yan’s Radish: Between the Real and the Surreal” Xiaoyue Li and Xuefang Feng argue that Radish, a novella written by Nobel Prize winner Mo Yan skillfully combines realism with surrealism, the flexible swing between which is made possible by the choice of children’s perspective, and the effect is too significant to be ignored. Their analysis concludes that the transparent golden radish symbolizes humanity, the lack of which projects the protagonist’ sufferings, and that the surrealist description of the radish reveals the magic function of humanity in brightening up life in times of miseries

Existence and uniqueness of solutions for singular fourth-order boundary value problems

AbstractBy mixed monotone method, the existence and uniqueness are established for singular fourth-order boundary value problems. The theorems obtained are very general and complement previous known results

Dynamical Behavior of the Stochastic Delay Mutualism System

We discuss the dynamical behavior of the stochastic delay three-specie mutualism system. We develop the technique for stochastic differential equations to deal with the asymptotic property. Using it we obtain the existence of the unique positive solution, the asymptotic properties, and the nonpersistence. Finally, we give the numerical examinations to illustrate our results