Temperature acclimation of respiration and photosynthesis in the brown algaLaminaria saccharina

Sporophytes of the brown algaLaminaria saccharina (L.) Lamour grown at 15°C contained significantly more chlorophylla (chla) than did similar plants grown at 5°C. The increase in chla in 15°C plants was due to increased numbers of photosystem II reaction centes, and possibly to increased photosynthetic unit size, compared with 5°C plants. These changes were associated with increased values (photosynthetic efficiencies) in 15°C-grownL. saccharina relative to 5°C-grown plants. The changes in together with reduced respiration rates allowed 15°C-grownL. saccharina to achieve net photosynthesis and light-saturated photosynthesis at a lower photon fluence rate (PFR) than 5°C plants when both groups were assayed at the same temperature (15°C). The photon fluence rates necessary to reach the compensation point and achieve light-saturated photosynthesis (I _c andI _k , respectively) increased with increasing incubation temperature inL. saccharina grown at both 5 and 15°C. However, acclimation responses to growth temperature compensated for the short-term effect of temperature onI _c andI _k . Consequently, plants grown at 5 and 15°C were able to achieve similar rates of light-limited photosynthesis, and similarI _c andI _k values at their respective growth temperatures. These responses are undoubtedly important for perennial seaweeds such asL. saccharina, which frequently grow in light-limited habitats and experience pronounced seasonal changes in water temperature.Please address all correspondence and requests for reprints to I.R. Davison     

Dry aerial fallout of organochlorine insecticide residues in Delhi, India

Monitoring of airborne dust in Delhi during May to July 1985 revealed residues of DDT varying from 1.3 to 7.14 ng mg(-1) (4.06-22.31 ng m(-2) day(-1)) with an average of 3.32 ng mg(-1) (10.38 ng m(-2) day(-1)), and HCH which ranged from 0.46 to 2.35 ng mg(-1) (1.44-7.34 ng m(-2) day(-1)) with a mean of 1.16 ng mg(-1) (3.63 ng m(-2) day(-1)). The concentration of total DDT was almost 3 times greater than that of HCH.     

Yield and grain quality of spring wheat (Triticum aestivum L., cv. Drabant) exposed to different concentrations of ozone in open-top chambers

Spring wheat (Triticum aestivum L., cv. Drabant) was exposed to different concentrations of ozone in open-top chambers for two growing seasons, 1987 and 1988, at a site located in south-west Sweden. The chambers were placed in a field of commercially grown spring wheat. The treatments were charcoal-filtered air (CF), non-filtered air (NF) and non-filtered air plus extra ozone (NF(+)). In 1988, one additional ozone concentration (NF(++)) was used. Grain yield was affected by the ozone concentration of the air. Air filtration resulted in an increase in grain yield of about 7% in both years, compared to NF. The addition of ozone (NF(+), NF(++)) reduced grain yield and increased the content of crude protein of the grain in both years. Filtration of the air had no significant effect on the content of crude protein, compared to NF. The results showed a strong positive chamber effect on grain yield in the cold and wet summer of 1987. In 1988, there was no net chamber effect on grain yield. The relative differences between the CF, NF and NF(+) treatments with respect to grain yield were of the same magnitude in the two years, despite the very different weather conditions.     

Plastic pellets, tar, and megalitter on Beirut beaches, 1977-1988

In the spring of 1988, five beaches along the coast of Beirut were surveyed for the presence of plastic pellets, tar, and megalitter--a follow-up to the studies conducted on the coast of Lebanon in 1977 for plastic pellet and tar occurrence, and in 1978 for containers and other megalitter on Beirut beaches. Plastic pellets were more abundant than they were in 1977 on three beaches and less so on two. Tar, however, seemed to occur much more abundantly on all five beaches. Megalitter, chiefly plastic but also paper, metal, and glass, had increased greatly compared with that seen 10 years ago. As in 1977, the unrestricted waste disposal practices of the plastic manufacturers, plus the possible loss of cargo from ships loading and unloading raw materials, are the most likely sources of plastic pellets. The abundance of tar is not surprising, considering that the Mediterranean Sea is tar-polluted and that two oil terminals occur on Lebanon's coast. Further, local gas stations frequently dump oil and grease onto the beaches, and numerous fires have occurred at coastal refineries over the past 10-15 years. All of these factors are likely to contribute to the presence of tar on the beaches. The main source of the vast quantities of megalitter on the beaches is undoubtedly the Lebanese people themselves, due to numerous population shifts and the lack of order and regulatory enforcement as a result of the civil chaos in the country. In addition, the ships docking or waiting for days, and sometimes weeks, to get into the Lebanese ports probably affect the abundance of megalitter (and tar) on the beaches.     

Impact of sulphur dioxide exposure on conidial germination of powdery mildew fungi

The impact of sulphur dioxide, in two different concentrations (286 microg m(-3) and 571 microg m(-3)) for various exposure periods, on conidial germination of some powdery mildew fungi was investigated in artificial treatment conditions. SO(2) in general was inhibitory for conidial germination of all the studied powdery mildew fungi and the species did not differ much from each other in their sensitivity to SO(2). The per cent conidial germination was increasingly inhibited with an increase in the concentration of SO(2). The concentration of SO(2) and the exposure period were important determinants of the inhibitory effect.     

The effect of chronic toxicity of copper on the activity of Balbiani rings and nucleolar organizing region in the salivary gland chromosomes of Chironomus ninevah larvae

The effect of copper on the activity of Balbiani rings (BR1 and BR2) and nucleolar organizing region (NOR) in chromosome IV of the salivary gland of the 4th instar larvae of Chironomus ninevah has been investigated. Sublethal concentrations, i.e. 0.02, 0.1, 0.15 and 0.2 mg litre(-1) suppress the activity of BR1, and are statistically significant. The same concentrations reduced the activity of BR2 and NOR, but without significant differences, except 0.1 mg litre(-1) which was significant. The purpose of this work was to evaluate the effect of chronic toxicity of Cu(2+) on the expression of gene activity of midge salivary gland chromosomes Although there may be many more aquatic organisms that are more sensitive to copper, this midge was selected as a biological indicator species because of its association with benthic sediments.     

Effects of elevated CO2 concentration on the polyamine levels of field-grown soybean at three O3 regimes

Effects of increased ozone (O3) and carbon dioxide (CO2) on polyamine levels were determined in soybean (Glycine max L. Merr. cv. Clark) grown in open-top field chambers. The chamber treatments consisted of three O3 regimes equal to charcoal filtered (CF), non-filtered (NF), and non-filtered plus 40 nl litre(-1) O3 and CO2 treatments equal to 350, 400 and 500 microl litre(-1) for a total of nine treatments. Leaf samples were taken at three different times during the growing season. Examination of growth and physiological characteristics, such as photosynthesis, stomatal resistance, and shoot weight, revealed that increasing CO2 ameliorated the deleterious effects of increased O3. Results from the initial harvest, at the pre-flowering growth stage (23 days of treatment), showed that increasing O3 at ambient CO2 caused increases in putrescine (Put) and spermidine (Spd) of up to six-fold. These effects were lessened with increased CO2. Elevated CO2 increased polyamines in plants treated with CF air, but had no effect in the presence of ambient or enhanced O3 levels. Leaves harvested during peak flowering (37 days of treatment) showed O3-induced increases in Put and Spd at ambient CO2 concentrations. However, increased CO2 levels inhibited this response by blocking the O3-induced polyamine increase. Leaves harvested during the pod fill stage (57 days of treatment) showed no significant O3 or CO2 effects on polyamine levels. Our results demonstrate that current ambient O3 levels induce the accumulation of Put and Spd early in the growing season and that further increases in O3 could result in even greater polyamine increases. These results are consistent with a possible antiozonant function for polyamines. The ability of increased CO2 to protect soybeans from O3 damage, however, does not appear to involve polyamine accumulation.     

The influence of acidic mine and spoil drainage on water quality in the mid-Wales area

The many abandoned base metal mines of the mid-Wales ore field are sources of extensive pollution. Some of the mineralised veins contain large amounts of pyrite and marcasite and oxidative weathering of these produces sulphuric acid resulting in very acidic mine drainage waters. In addition, the spoil tips associated with these mines can contain abundant iron sulphides. Drainage waters from these sources have pH values as low as 2.6 and are heavily contaminated with metals such as Al, Zn, Cd and Ni.Two of the main rivers of the area, the Rheidol and Ystwyth, intercept heavily contaminated acidic drainage which has a marked effect on water quality. The Rheidol contains over 100 g L^–1 Zn for 16 km downstream of the acid water influx. This level is over three times the recommended EEC limit for Zn in salmonoid waters of low hardness.     

Low frequency of extra-pair paternity in pied flycatchers revealed by DNA fingerprinting

Summary Genetic parentage of 135 nestlings from 27 broods of polygynous and monogamous pied flycatchers Ficedula hypoleuca was analyzed by means of multilocus DNA fingerprinting. The minisatellite probe alpha-globin 3HVR detected approximately 12 scorable bands per fingerprint, and the proportion of bands shared between presumably unrelated adults averaged 0.22+0.08 SD. The fingerprints of 125 of the 135 nestlings made a complete match to those of their putative parents. In 4 nestlings a single mismatched band occurred, but since band sharing with both putative parents was high, the single mismatches were assumed to be caused by mutation. The 6 remaining nestlings had 5 or more mismatched bands each, low band-sharing proportions with their putative father and high band-sharing proportions with their putative mother. We thus conclude that they were all sired through extra-pair copulations (EPCs). Hence, only 4% of nestlings were sired through EPCs, and none resulted from intraspecific brood parasitism. One of the cuckolding males was identified, explaining all 5 mismatched bands in the nestling's fingerprint. Three of the illegitimate nestlings were from primary nests of polygynous males; 3 were from nests of monogamous males. The fact that many males in this study started to advertise for a second female in a distant territory several days before their first mate began egglaying, and still managed to secure almost exclusive paternity in their first brood, suggests that male polyterritoriality is not costly in terms of lost paternity. Common anti-cuckoddry tactics performed by male birds, like high rate of within-pair copulation and continuous mate-guarding thoughout the female's fertilizable period, do not seem to be important in pied flycatchers.Offprint requests to: J.T. Lifjeld