Whereas most plant suspension cultures are grown heterotrophically in the presence of sugars, a limited number of photoautotrophic cultures have been established which are able to grow with CO2 as the sole carbon source. Photoautotrophic cultures are useful to address various aspects of photosynthesis, source-sink regulation, nitrogen metabolism, production of secondary metabolites, and defence responses. The homogenous populations of these cultures provide an ideal and sensitive system to obtain reproducible results. The availability of an increasing number of photoautotrophic cultures from different economically important species provides the basis also for practical applications. and T. Roitsch, A. K. Sinha.
Changes in leaf growth, net photosynthetic rate (PN), incorporation pattern of photosynthetically fixed 14CO2 in leaves 1-4 from top, roots, and rhizome, and in essential oil and curcumin contents were studied in turmeric plants grown in nutrient solution at boron (B) concentrations of 0 and 0.5 g m-3. B deficiency resulted in decrease in leaf area, fresh and dry mass, chlorophyll (Chl) content, and PN and total 14CO2 incorporated at all leaf positions, the maximum effect being in young growing leaves. The incorporation of 14CO2 declined with leaf position being maximal in the youngest leaf. B deficiency resulted in reduced accumulation of sugars, amino acids, and organic acids at all leaf positions. Translocation of the metabolites towards rhizome and roots decreased. In rhizome, the amount of amino acids increased but content of organic acids did not show any change, whereas in roots there was decrease in contents of these metabolites as a result of B deficiency. Photoassimilate partitioning to essential oil in leaf and to curcumin in rhizome decreased. Although the curcumin content of rhizome increased due to B deficiency, the overall rhizome yield and curcumin yield decreased. The influence of B deficiency on leaf area, fresh and dry masses, CO2 exchange rate, oil content, and rhizome and curcumin yields can be ascribed to reduced photosynthate formation and translocation. and Deeksha Dixit, N. K. Srivastava, S. Sharma.
We studied feeding intake and food selection of nine captive forest musk deer (Moschus berezovskii) offered 17 species of plants in China. We also determined nutrient characteristics related to plant quality to assess their effect on food selection. Results indicated that forest musk deer exhibited positive selectivity for four species of plants (M. azedarach, M. baccata, K. japonica and C. orbiculatus) and negative selectivity for the remainder. Two plant species with the highest selectivity values accounted for 47.39 % of total food intake; thus, forest musk deer exhibited the strongest preference for these species. Food intake was positively correlated with feeding frequency and duration (r = 0.764, p < 0.005; r = 0.843, p < 0.005) but was not correlated with sniffing frequency or duration. However, olfaction did play an important role in food recognition by the deer. Pearson correlation analysis (data were log10 transformed) indicated that leaf intake was positively correlated with crude protein content (r = 0.708, p = 0.001) and negatively correlated with crude fiber content (r = –0.811, p < 0.001) and ash content (r = –0.496, p = 0.043). In addition, forest musk deer preferred tannin-rich plants with high protein and low fiber. Food intake was also positively correlated with potassium content (r = 0.672, p < 0.005). Our results suggest that forest musk deer is able to positively select high quality food (high protein content) and avoid low quality food (high fiber content). However, the fact that musk deer also prefer tannin-rich food requires further research to gain deeper insight into the underlying mechanisms in the food selection of forest musk deer.
We collected specimens of Paramecops sinaitus (Pic, 1930) (Curculionidae: Molytinae) from south Sinai in Egypt, which enabled us to make the first complete description of this species. We also include some taxonomic remarks on the genus. Paramecops solenostemmatis (Peyerimhoff, 1930) is a synonym of Paramecops sinaitus. We propose the new combination Paramecops sogdianus (Nasreddinov, 1978), based on Perihylobius sogdianus Nasreddinov, 1978, which would make Perihylobius and Paramecops synonymous. Like other Paramecops species, P. sinaitus appears to share a close interaction with Asclepiads, in this case the Sinai milkweed Asclepias sinaica (Boiss.) Muschl., 1912 (Asclepiadaceae). We investigated the oviposition behaviour of female weevils to test whether it is linked to larval performance, as predicted by coevolutionary theory. We found that female oviposition preference was positively related to plant size and to the volume of the seed follicles in which the eggs were laid. The survival of eggs was negatively related to plant size, perhaps due to plant differences in the production of defensive cardenolides. Larval survival was not related to plant size but increased with follicle volume, probably as a result of competition for food. Paramecops is relatively sedentary and nocturnal in its behaviour. Night-time observations of behaviour showed that weevils were more active at lower temperatures.