Das Carotinoidmuster vonLophocolea bidentata (L.)Dum.

Zusammenfassung Das Carotinoidmuster vonLophocolea bidentata (L.)Dum. wurde mit Hilfe von Adsorptions- und Verteilungschromatographie auf Dünnschichten sowie durch Ermittlung von Absorptionsspektren im sichtbaren Bereich und im UV untersucht. Folgende Carotine und Xanthophylle konnten auf diese Weise isoliert und identifiziert werden: -Carotin, -Carotin, Neo--Carotin U, Zeaxanthin, mono-cis-Neoxanthin, trans-Neoxanthin, poly-cis-Neoxanthin, Violaxanthin Neo V, Violaxanthin, Antheraxanthin, Lutein und Lutein-5,6-Epoxid.

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Summary The carotenoids ofLophocolea bidentata (L.)Dum. have been investigated by adsorption and partition TLC and through their visible and UV spectra. The following carotenes and xanthophylls have been isolated and identified: -carotene, -carotene, neo--carotene U, zeaxanthin, mono-cis-neoxanthin, trans-neoxanthin, poly-cis-neoxanthin, Violaxanthin neo V, violaxanthin, antheraxanthin, lutein, and lutein-5,6-epoxide.

     

Salt tolerance in the halophyte Suaeda maritima L. Dum.

Osmotic potentials and individual epidermal cell turgor pressures were measured in the leaves of seedlings of Suaeda maritima growing over a range of salinities. Leaf osmotic potentials were lower (more negative) the higher the salt concentration of the solution and were lowest in the youngest leaves and stem apices, producing a gradient of osmotic potential towards the apex of the plant. Epidermal cell turgor pressures were of the order of 0.25 to 0.3 MPa in the youngest leaves measured, decreasing to under 0.05 MPa for the oldest leaves. This pattern of turgor pressure was largely unaffected by external salinity. Calculation of leaf water potential indicated that the gradient between young leaves and the external medium was not altered by salinity, but with older leaves, however, this gradient diminished from being the same as that for young leaves in the absence of NaCl, to under 30% of this value at 400 mM NaCl. These results are discussed in relation to the growth response of S. maritima.     

Caudal Musculature of the South Indian Flying Lizard Draco dussumieri Dum. and Bibr.

The modifications noticed in the caudal musculature of the South Indian Flying Lizard, Draco dussumieri, are described. The caudal musculature consists of the superficial ilio-caudalis and ischio-caudalis and the deeper ventral caudo-femoralis brevis and caudo-femoralis longus. There is an accessory tendon extending between the outer border of the tendon of the caudo-femoralis longus and the tendinous origin of the gastrocnemius. In the male the copulatory organ is provided with a retractor muscle. Attached to the ventral surface of the penis sheath is another muscle which helps in everting the penis. This latter muscle is present in the female also as a vestigeal one attached to the postero-lateral corners of the cloacal chamber. The modifications in the caudal musculature are attributable to the gliding habits of this lizard. Draco dussumieri, the South Indian Flying Lizard is unique in having a patagium for gliding from tree to tree. Associated with the development of the patagium, the musculature has undergone a number of adaptive modifications. The modifications of the trunk musculature have been published elsewhere (John 1970). The present communication is a study of the caudal musculature of this lizard.     

The Physiology of Sexual Reproduction in Lunularia cruciata (L.) Dum.

Abstract

Since 1794 about 1.3 species per year have been added to the known bryophyte flora of Oxfordshire.This is chiefly due to taxonomic research combined with diligent and intelligent collecting but it is also partly due to the immigration or at least the increasing frequency of some species. Twenty- five species (ca 7% of the flora) have not been recorded during the present century, and may be extinct, but many more have declined in frequency. The paper seeks to elucidate the extent and the causes of such changes; for this purpose much evidence from other districts is reviewed.

Apart from the physical destruction of local specialized habitats and the creation of new habitats, the more important causes of widespread change have been: (a) eutrophication of both land and water, partly as a result of (b) changes in agricultural practice, including the heavy application of fertilizers, and immediate ploughing and resowing after harvest; (c) a decline in grazing, especially by rabbits; (d) changes in forestry practice, including the cessation of coppicing and the planting of conifers, increasing the amount of decaying woody material; (e) most far-reaching of all, widespread but slight atmospheric pollution, the effect of which seems to be due to ‘acid rain’ rather than to toxic SO₂.

Factors (d) and (e), though adverse for basiphil species, have favoured acidiphil species, at least eight of which have increased in frequency. An additional four acidiphil species first recorded in the county since 1935 have remained rare, but evidence from other districts suggests that they are increasing.

Some dioecious mosses formerly fruited more freely in Oxfordshire than they do now.     

Salt Tolerance in the Halophyte Suaeda maritima L. Dum.: Intracellular Compartmentation of Ions

The time-course of exchange of sodium and potassium ions fromroot and leaf material of the halophyte Suaeda maritima hasbeen followed and the data analysed according to the phenomenologyof efflux, or compartmental, analysis. Sodium ions were exchangedmuch more slowly (c. 4 times) from the vacuoles of leaf cellsof plants grown in sodium chloride than were potassium ionsfrom the vacuoles of leaf cells of plants grown either in similarconcentrations of potassium chloride or in low concentrationsof potassium. In plants grown in sodium chloride, sodium ionswere exchanged 9 times more slowly from the vacuoles of leafcells than from the vacuoles of root cells. The concentration of sodium ions in the cytoplasm of leaf cellsof plants growing in 340 mol m^–3 sodium chloride was estimatedto be 165 mol m^–3 when the average concentration in theleaf tissue was about 600 mol m^–3. As measured by movement from mature to developing leaves inintact plants; there was less in vivo retranslocation of ²²Naand ³⁶CI in plants growing in sodium chloride than there wasof ⁸⁶Rb in plants growing either in potassium chloride or innon-saline conditions. The results are discussed in terms of the concept and energeticsof compartmentation of ions in the cells of halophytes.