The effects of NaCl stress on the growth and photosynthetic characters of Ulmus pumila L. seedlings were investigated under sand culture condition. With increasing NaCl concentration, main stem height, branch number, leaf number, and leaf area declined, while Na+ content and the Na+/K+ ratio in both expanded and expanding leaves increased. Na+ content was significantly higher in expanded leaves than in those just expanding. Chlorophyll (Chl) a and Chl b contents declined as NaCl concentration increased. The net photosynthetic rate, intercellular CO2 concentration, stomatal conductance, and transpiration rate also declined, but stomatal limitation value increased as NaCl concentration increased. Both the maximal quantum yield of PSII photochemistry and the effective quantum yield of PSII photochemistry declined as NaCl concentration rose. These results suggest that the accumulation of Na+ in already expanded leaves might reduce damage to the expanding leaves and help U. pumila endure high salinity. The reduced photosynthesis in response to salt stress was mainly caused by stomatal limitation., Z. T. Feng, Y. Q. Deng, H. Fan, Q. J. Sun, N. Sui, B. S. Wang., and Obsahuje bibliografii
In the paper by Hilout and Piétrus (2006) a semilocal convergence analysis was given for the secant-like method to solve generalized equations using Hölder-type conditions introduced by the first author (for nonlinear equations). Here, we show that this convergence analysis can be refined under weaker hypothesis, and less computational cost. Moreover finer error estimates on the distances involved and a larger radius of convergence are obtained.
It is known that the ring $B(\mathbb R)$ of all Baire functions carrying the pointwise convergence yields a sequential completion of the ring $C(\mathbb R)$ of all continuous functions. We investigate various sequential convergences related to the pointwise convergence and the process of completion of $C(\mathbb R)$. In particular, we prove that the pointwise convergence fails to be strict and prove the existence of the categorical ring completion of $C(\mathbb R)$ which differs from $B(\mathbb R)$.