THE DISTRIBUTION AND ACCUMULATION OF SELENIUM IN ROOTS AND SHOOTS OF PLANTS NATURALLY GROWN IN THE SOILS OF KEBAN’S PB-ZN-F MINING AREA,TURKEY

The objective of this study is to determine the distribution factors and enrichment coefficients between soil and plant parts by studying the accumulation and distribution of selenium (Se) in the roots and shoots of different plants. The plants (9 samples of Euphorbia macroclada, 5 samples of Verbascum cheiranthifolium, 8 samples of Astragalus gummifer) and their associated soil samples were collected from the Keban mining area. The roots and the shoots of these plants, together with the associated soils, were analyzed by ICP-MS. The mean Se value of the contaminated surface soils was found to be two to five times higher than those of previously studied uncontaminated surface soils. Se concentrations of the plant parts were lower than those in their associated alkaline soils, where the plants were grown, except for in the shoots of A. gummifer. Mean Se concentrations in the roots of E. macroclada, V. cheiranthifolium, and A. gummifer were 0.82, 0.22, and 0.47 mg kg^?1 on a dry weight basis, respectively, while Se concentrations were 0.29, 0.26, and 2.66 mg kg^?1 in the shoots on a dry weight basis, respectively. The enrichment coefficients and the distribution factors of those plants were lower than 1, except for the distribution factors of V. cheiranthifolium and A. gummifer plants. Thus, it appeared that the shoots of these plants could make them efficient bioaccumulator plants for Se because of high distribution factors and enrichment coefficients. Due to such factors, they can also be used to clean or rehabilitate soils and areas contaminated with Se.     

THE TIME AND SITE OF THE SEMIDOMINANT LETHAL ACTION OF “Wo” IN LYCOPERSICON ESCULENTUM

Huang , P. C. (California Inst. Technol., Pasadena), and E. F. Paddock . The time and site of the semidominant lethal action of “Wo” in Lycopersicon esculentum. Amer. Jour. Bot. 49(4): 388–393. Illus. 1962.—The semidominant lethal gene, Wo (Woolly), in Lycopersicon esculentum has been investigated with specific attention to its lethal action. The primary lethal action is believed to occur prior to the torpedo stage of embryonic development (approximately 22 days after anthesis). The presumed WoWo embryos cease to grow before any cambial differentiation or organogenesis can be recognized. Their accompanying endospermous cells, however, continue to divide, this resulting in full-sized seeds. The death of these embryos probably occurs near the time of maturation of the seeds (approximately 52 days after anthesis or when the ovulary turns orange-red). The mechanism of death of the embryo apparently lies in and is specific to the embryo; hence, this is a case of autogenously determined embryonic lethality.     

THE OCCURRENCE OF “ROOT GAPS” IN THE RHIZOME SOLENOSTELE AND LEAF TRACE OF DENNSTAEDTIA CICUTARIA

The vascular system of the rhizome axes of Dennstaedtia cicutaria consists of a solenostele with an amphicribral vascular bundle centrally located in the pith. Each leaf has a single trace which is an amphicribral vascular bundle. At each node of an axis there is a complex consisting of the main axis, leaf base, and a branch axis attached to the basiscopic margin of the leaf base. Numerous roots are present on the rhizomes and the abaxial side of the leaf bases. Parenchymatous gaps occur in the rhizome solenostele and the leaf trace directly above the departure of some of the root traces. These gaps are termed root gaps. In some instances the root gaps are confluent. However, not all of the root traces have an associated root gap. The leaf trace is inserted laterally on the main and branch axes at the node so that the acroscopic leaf trace margin anastomoses with the main axis of the vascular system and the basiscopic margin with that of the branch axis. Two leaf gaps are associated with each leaf trace, one occurring in the main axis solenostele and the other in the branch axis solenostele. The medullary bundle of each axis anastomoses with each leaf trace at its point of attachment to the rhizome solenostele. Thus, the medullary bundle forms a continuous vascular strand from leaf trace to leaf trace in any given rhizome axis.     

NOTE ON THE EXCITATION AND INHIBITION OF LUMINESCENCE IN BER?

1. The ions of Ca and K condition general luminescence, and are therefore necessary to the conduction of the impulse. 2. In van''t Hoff''s solution from which Mg is omitted, Berœ shows hyperirritability with respect to luminescence. This is the result of the action of Ca and K ions unantagonized by Mg. 3. The luminescent material spread on filter paper does not show luminescence in sea water, NaCl, MgCl₂, or saccharose solutions isotonic with sea water. In solutions of CaCl₂, SrCl₂, BaCl₂, KCl, and K₂SO₄ the indicator paper glows with a bright luminescence. 4. In dark adapted Berœ, luminescence is inhibited by a certain quantity of light. This quantity has an average value of 57,285 meter-candle-minutes, which is twelve times the value given by Mnemiopsis.     

ASSESSING THE CONTAMINATED LEVELS AND RISK OF TYPICAL CONTAMINANTS IN THE UPPER REACHES OF THE YANGTZE RIVER北大核心CSCD

We generally reviewed the distributions and potential risks of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in the upper reaches of the Yangtze River based on recent studies. The distribution of heavy metals varied significantly with locations and types of mediums, and contents of some metals exceeded the limits in food. The contents of PAHs in the upper reaches of the Yangtze River were in line with those in the lower reaches. Low molecular weight PAHs were predominant in surface water, while high molecular weight PAHs were predominant in sediments, indicating low molecular PAHs may pose greater risks to aquatic ecosystems. DEHP and DBP were the predominant monomers of PAEs in surface water and sediments, and BBP and DBP ranked first and second respectively in fish bodies. The results of risk assessment also indicated that monomers such as DBP and DnBP had greater risk than DEHP. Over all, heavy metals and organic pollutants were widely distributed in the aquatic environment in the upper reaches of the Yangtze River, which may pose potential risks to the ecosystem. © 2019, Institute of Hydrobiology, Chinese Academy of Sciences. All rights reserved.     

CONTAMINATED LEVEL AND RISK ASSESSMENT OF PAES IN THE UPPER REACHES OF THE YANGTZE RIVER北大核心CSCD

PAEs have been proved to be one of the major organic pollutants. The present study determined the level of PAEs using surface water samples from the upper reaches of the Yangtze River. The results showed that DEHP contributed the most to PAEs pollution, followed by DBP. Risk Quotients of PAEs were used for preliminary screening, and DEHP and BBP were identified as potential risk factors with RQ of 310 and 70.7. The MOS10 of DEHP and BBP were 1.40 and 1.32×105, respectively, indicating that BBP may pose little risk to aquatic organisms. The potential risk of DEHP was further analyzed with joint probabilistic curves. Among different biological groups, fish and zoobenthos were two major groups sensitive to DEHP-induced damage under current concentrations with 99.4% and 98.3% for 5% species of each group. While among the toxicity endpoints, reproduction may be more sensitive than others. The 5% and 10% aquatic species were suffered from reproductive damages by 100% and 97.8%, respectively. Overall, our results indicated that DEHP in the surface water of the upper Yangtze River may pose potential risk to aquatic organisms, especially on their reproduction. Therefore, more concerns should be paid in species protection and environmental management. © 2019, Institute of Hydrobiology, Chinese Academy of Sciences. All rights reserved.