Leaf chlorophyll (Chl) concentration can be an indicator of plant health, including photosynthetic potential and nutrient status. In some cases, this measure can indicate the degree to which plants are water-stressed. Traditional methods of measuring Chl concentration have involved a destructive sampling technique: extraction and spectrophotometric analysis. A compatible nondestructive method to measure leaf Chl concentration exists and applies transmittance spectroscopy to plants with a Minolta SPAD-502 meter. These techniques were evaluated by comparing leaf Chl concentration in big bluestem (Andropogon gerardii). Leaves were sampled from plants representing three ecotypes (originating from Central Kansas, Eastern Kansas, and Illinois, USA) and two cultivars of A. gerardii growing in Hays, Kansas, USA. Leaf Chl concentration was measured using nondestructive and destructive techniques. We documented a saturating relationship between destructively measured leaf Chl concentration and SPAD index resulting from a decelerating change in SPAD index as Chl concentration increased. The comparison of A. gerardii ecotypes and cultivars demonstrated highest Chl concentration in the ecotype and cultivar from areas with historically low precipitation, Central Kansas and A. gerardii var. hallii, respectively. A high ratio of Chl a to Chl b is an index of drought adaptation and was also manifested in A. gerardii from drier regions. Thus, drought-adapted ecotypes and cultivars might be able to maintain high photosynthetic productivity and protect photosystem II during dry periods. Conversely, the ecotypes and cultivar originating from areas with higher precipitation had lower leaf Chl and a lower Chl a/b ratio., K. L. Caudle, L. C. Johnson, S. G. Baer, B. R. Maricle., and Obsahuje bibliografii
Galanin and galanin receptors (GalRs) have been reported to be
involved in the transmission and modulation of nociceptive
information in the central nervous system (CNS). However, the
underlying mechanism of the antinociception of GalRs in
neuropathic pain remains unclear. This study investigated the
antinociception induced by galanin receptor 1 (GalR1) via protein
kinase A (PKA) signaling pathway in the nucleus accumbens
(NAc) of rats with neuropathic pain. A mononeuropathy model
was replicated by ligation of the left sciatic nerve, following which
the expression of phospho-PKA (p-PKA) in the NAc were
markedly up-regulated at 14th and 28th day after ligation of sciatic
nerve, and p-PKA expression was down-regulated by intra-NAc
injection of GalR1 agonist M617, but the GalR1 antagonist M35
did not have an effect. We also found that M35 in the NAc
blocked the M617-induced increase in the hind paw withdrawal
latencies (HWLs) of rats with mononeuropathy, but M35 alone
had no effect on HWLs, and PKA inhibitor H-89 attenuated the
M617-induced an increase in the HWLs. These results suggested
that GalR1 induced an antinociception via inhibiting PKA
activation, implying that GalR agonists may be potential and
potent therapeutic options to treat chronic neuropathic pain.