Nondestructive methods to estimate individual leaf area (LA) accurately, by leaf length (L) and/or width (W), is helpful for the in situ and successive LA measurements. However, leaf shape and size may covary with environment and thus alter the coefficients of LA estimation models. To test such hypothesis, we carried out an experiment by measuring Saussurea stoliczkai C. B. Clarke leaves along an altitudinal transect in Damxung county, central Tibet. In July 2011, we selected seven sites at about every 150 m in altitude from 4,350 m to 5,250 m a.s.l. A total of 1,389 leaves (182 to 203 leaves for each site) were measured. For each site, models developed by two leaf dimensions [LA = a (L×W) + b] could estimate LA more accurately than those by single dimension. L, W, LA and leaf shape index (L:W ratio) all decreased with increasing altitude, leading to significant differences in coefficients of two-dimension model between almost every two sites. Accordingly, a common
two-dimension model is unlikely to occur for S. stoliczkai across the whole altitudinal transect, indicating that the varying leaf shape may alter the coefficient of LA estimation models., Z. Wang, L. Zhang., and Obsahuje bibliografii
Tropical rainforest trees adjust leaf traits during ontogeny to cope with changes in the physical environment and maximize their carbon uptake. The aim of this study was to determine the plasticity index (PI) of leaf traits in understory and canopy leaves of six Amazonian tree species. In four of the six species the PI of leaf traits varied within species, and in four of the ten leaf traits assessed, the PI differed between species. The greatest PI values were found for stomatal density (Ds) and CO2-saturated photosynthesis, and the lowest ones were found for stomatal size, and leaf thickness. Despite the differences in PI values within species, the mean PI was similar in all the six species. As the saplings grow toward the canopy, the strategy to increase carbon uptake involves increasing Ds and leaf nitrogen and reducing stomatal size., R. A. Marenco, M. A. B. Camargo, S. A. Antezana-Vera, M. F. Oliveira., and Obsahuje seznam literatury
Global climate change may act as a potent agent of natural selection within species with Mediterranean mountain ecosystems being particularly vulnerable. The aim of this research was to analyze whether the phenotypic plasticity of Sesleria nitida Ten. could be indicative of its future adaptive capability to global warming. Morphological, anatomical, and physiological leaf traits of two populations of S. nitida growing at different altitudes on Mount Terminillo (Italy) were analyzed. The results showed that leaf mass per unit leaf area, leaf tissue density, and total leaf thickness were 19, 3, and 31% higher in leaves from the population growing at 1,895 m a.s.l. (B site) than in leaves from the population growing at 1,100 m a.s.l. (A site), respectively. Net photosynthetic rate (PN) and respiration rate (RD) peaked in June in both A and B leaves [9.4 +- 1.3 μmol(CO2) m-2 s-1 and 2.9 +- 0.9 μmol(CO2) m-2 s-1, respectively] when mean air temperature was 16 +- 2°C. R D/P N was higher in B than in A leaves (0.35 +- 0.07 and 0.21 +- 0.03, respectively, mean of the study period). The mean plasticity index (PI = 0.24, mean of morphological, anatomical, and physiological leaf traits) reflected S. nitida adaptability to the environmental stress conditions at different altitudes on Mount Terminillo. Moreover, the leaf key traits of the two populations can be used to monitor wild populations over a long term in response to global change., L. Gratani, M. F. Crescente, V. D’Amato, C. Ricotta, A. R. Frattaroli, G. Puglielli., and Obsahuje bibliografii
Using measures of gas exchange and photosynthetic chain activity, we found some differences between grapevine inflorescence and leaf in terms of photosynthetic activity and photosynthesis regulations. Generally, the leaf showed the higher net photosynthesis (PN) and lower dark respiration than that of the inflorescence until the beginning of the flowering process. The lower (and negative) PN indicated prevailing respiration over photosynthesis and could result from a higher metabolic activity rather than from a lower activity of the photosynthetic apparatus. Considerable differences were observed between both organs in the functioning and regulation of PSI and PSII. Indeed, in our conditions, the quantum yield efficiency and electron transport rate of PSI and PSII were higher in the inflorescence compared to that of the leaf; nevertheless, protective regulatory mechanisms of the photosynthetic chain were clearly more efficient in the leaf. This was in accordance with the major function of this organ in grapevine, but it highlighted also that inflorescence seems to be implied in the whole carbon balance of plant. During inflorescence development, the global PSII activity decreased and PSI regulation tended to be similar to the leaf, where photosynthetic activity and regulations remained more stable. Finally, during flowering, cyclic electron flow (CEF) around PSI was activated in parallel to the decline in the thylakoid linear electron flow. Inflorescence CEF was double compared to the leaf; it might contribute to photoprotection, could promote ATP synthesis and the recovery of PSII., M. Sawicki, B. Courteaux, F. Rabenoelina, F. Baillieul, C. Clement, E. Ait Barka, C. Jacquard, N. Vaillant-Gaveau., and Obsahuje bibliografii
Tropical canopy tree species can be classified into two types by their heterobaric and homobaric leaves. We studied the relation between both leaf types and their water use, together with the morphological characteristics of leaves and xylem, in 23 canopy species in a tropical rain forest. The maximum rates of photosynthesis and transpiration were significantly higher in heterobaric leaf species, which also underwent larger diurnal variations of leaf water potential compared to homobaric leaf species. The vessel diameter was significantly larger and the stomatal pore index (SPI) was significantly higher in heterobaric than that in homobaric leaf species. There was a significant positive correlation between the vessel diameter, SPI, and maximum transpiration rates in all the studied species of both leaf types. However, there was no significant difference in other properties, such as leaf water-use efficiency, leaf mass per area, leaf nitrogen content, and leaf δ13C between heterobaric and homobaric leaf species. Our results indicate that leaf and xylem morphological differences between heterobaric and homobaric leaf species are closely related to leaf water-use characteristics, even in the same habitat: heterobaric leaf species achieved a high carbon gain with large water use under strong light conditions, whereas homobaric leaf species can maintain a high leaf water potential even at midday as a result of low water use in the canopy environment., Y. Inoue, T. Kenzo, A. Tanaka-Oda, A. Yoneyama, T. Ichie., and Obsahuje bibliografii
Water-lilies (the genus Nymphaea) are one of the most ancient groups of aquatic plants. Two species (N. alba and N. candida) are native to the flora of the Czech Republic, both are critically endangered. Morphological similarities, large phenotypic variation and putative interspecific hybridization pose difficulties for species identification. The amount of nuclear DNA was found to be a reliable characteristic that allows not only species but also their hybrids to be re - cognized. Native species are mainly threa - tened by the loss of suitable habitats and planting of garden cultivars in natural sites. and Klára Kabátová, Petr Vít, Jan Suda.
A new species of the genus Lemuralges Fain, 1963 (Acariformes: Psoroptidae: Makialginae) is described from the Malagasy lemur Propithecus diadema (Bennett) (Primates: Indriidae) based on all postembryonic instars. This new species differs from the only known species in this genus, Lemuralges intermedius Fain, 1963, by the following features: both sexes of L. propithecus sp. n. show a pair of medioventral projections of the subcapitulum (vs without projections in L. intermedius) and the propodonotal shield is slightly ornamented (vs unornamented); in males the hysteronotal shield is completely covered by longitudinal striae (vs median part without striae), setae c2 are 120-140 µm long (vs 200-210 µm long), and femur III has a short transverse furrow dorsally (vs a longitudinal furrow); in females, setae h2 are, at least, 2 times shorter than h3 (vs slightly longer, or subequal to, h3), tibia IV has a ventro-apical projection (vs without projection). Larvae and protonymphs of the new species show some unique developmental delays. Female and male tritonymphs differ by their external morphology., Andre V. Bochkov, Hans Klompen, Randall E. Junge, Cathy V. Williams., and Obsahuje bibliografii