The influence of arbuscular mycorrhizal (AM) fungus Glomus deserticola (Trappe and John) on plant growth, nutrition, flower yield, water relations, chlorophyll (Chl) contents and water-use efficiency (WUE) of snapdragon (Antirhinum majus cv. butterfly) plants were studied in potted culture under well-watered (WW) and water-stress (WS) conditions. The imposed water stress condition significantly reduced all growth parameters, nutrient contents, flower yield, water relations, and Chl pigment content and increased the electrolyte leakage of the plants comparing to those of nonstressed plants. Regardless of the WS level, the mycorrhizal snapdragon plants had significantly higher shoot and root dry mass (DM), WUE, flower yield, nutrient (P, N, K, Mg, and Ca) and Chl contents than those nonmycorrhizal plants grown both under WW or WS conditions. Under WS conditions, the AM colonization had greatly improved the leaf water potential (Ψw), leaf relative water content (RWC) and reduced the leaf electrolyte leakage (EL) of the plants. Although the WS conditions had markedly increased the proline content of the leaves, this increase was significantly higher in nonmycorrhizal than in mycorrhizal plants. This suggests that AM colonization enhances the host plant WS tolerance. Values of benefit and potential dry matter for AM-root associations were highest when plants were stressed and reduced under WW conditions. As a result, the snapdragon plants showed a high degree of dependency on AM fungi which improve plant growth, flower yield, water relations particularly under WS conditions, and these improvements were increased as WS level had increased. This study confirms that AM colonization can mitigate the deleterious effect of water stress on growth and flower yield of the snapdragon ornamental plant., A. A. Asrar, G. M. Abdel-Fattah, K. M. Elhindi., and Obsahuje bibliografii
In this article we introduce the notion of strongly ${\rm KC}$-spaces, that is, those spaces in which countably compact subsets are closed. We find they have good properties. We prove that a space $(X, \tau )$ is maximal countably compact if and only if it is minimal strongly ${\rm KC}$, and apply this result to study some properties of minimal strongly ${\rm KC}$-spaces, some of which are not possessed by minimal ${\rm KC}$-spaces. We also give a positive answer to a question proposed by O. T. Alas and R. G. Wilson, who asked whether every countably compact ${\rm KC}$-space of cardinality less than $c$ has the ${\rm FDS }$-property. Using this we obtain a characterization of Katětov strongly ${\rm KC}$-spaces and finally, we generalize one result of Alas and Wilson on Katětov-${\rm KC}$ spaces.
The study aimed to determine the effects of protease-activated
receptor-2 (PAR-2) on glial scar formation after spinal cord injury
(SCI) in Sprague–Dawley (SD) rats and the underlying
mechanisms. Rivlin and Tator’s acute extradural clip compression
injury (CCI) model of severe SCI was established in this study.
Animals were divided into four groups: 1) sham group
(laminectomy only); 2) model group, treated with normal saline;
3) PAR-2 inhibitor group; 4) PAR-2 activator group. Enhanced
GFAP and vimentin expression were the markers of glial scar
formation. To determine whether JNK was involved in the effects
of PAR-2 on GFAP and vimentin expression, we administered
anisomycin (a JNK activator) in the presence of PAR-2 inhibitor
and SP600125 (a JNK inhibitor) in the presence of PAR-2
activator. At 1, 7, 14 and 28 day after SCI, Basso, Beattie, and
Bresnahan (BBB) locomotor score test was used to assess the
locomotor functional recovery; immunofluorescence and western
blot analysis were used to assess the expression level of GFAP,
vimentin and p-JNK. Double immunofluorescence staining with
GFAP and tubulin β was used to assess the glial scar formation
and the remaining neurons. Results suggested that PAR-2 is
involved in glial scar formation and reduces neurons residues
which can cause a further worsening in the functional outcomes
after SCI via JNK signaling. Therefore, it may be effective to
target PAR-2 in the treatment of SCI.