Chilling Tolerance Of Cicer Arietinum Lines Evaluated By Photosystem Ii And Antioxidant Activities

Two chickpea (Cicer arietinum L.) lines (AKN 87 and AKN 290) that have different chilling susceptibilities were exposed to 2 chilling temperatures (4 and 2 degrees C), either cold-acclimated (10 degrees C) or nonacclimated (25 degrees C), in order to understand and compare physiological and biochemical changes at the vegetative stage. Chilling temperatures resulted in reduced growth parameters, particularly in cold-acclimated lines, whereas nonacclimated plants exhibited the lowest water contents. Cold acclimation treatment led to protective changes of increased flavonoid, proline, and antioxidant enzyme activities, mostly superoxide dismutase (SOD) and ascorbate peroxidase (APX), in the lines. However, the 10 degrees C treatment did not significantly influence photosystem II (PSII) activity in chickpea plants. In chilling treatments, cold-acclimated plants exhibited better tolerance; of the 2 lines, AKN 87 had the higher PSII photochemical activity. The chlorophyll contents of lines decreased, while the anthocyanin and flavonoid contents of lines increased at decreasing temperatures. MDA and proline accumulation increased with the severity of the chilling stress. In conclusion, when the plants were exposed to cold acclimation, chilling induced the enhancement of antioxidant enzyme activities, particularly SOD and APX. The results demonstrated that cold acclimation reduced the deteriorative effects of chilling and provided better tolerance, specifically in AKN 87. The line AKN 87 has greater potential for cultivation as a chilling-tolerant cultivar.WoSScopu

Effects of Residual Xanthate on Flotation Efficiency of a Cu-Zn Sulfide Ore

Reuse of process water in the flotation of sulfide ores has crucial importance for environmental sustainability and improved process economy. However, the chemistry of process water may be a critical subject for the flotation efficiency as the dissolved ion concentration increases with water reuse. In this study, the effects of water reuse on the flotation efficiency of a Cu-Zn sulfide ore were investigated. The flotation flowsheet consists of a pre-flotation section to remove the naturally floatable talc particles, and sequential copper and zinc flotation sections. Calcium, sulfate, thiosulfate, and xanthate were found as major contaminating ionic species in the process water discharged from flotation circuits. The flotation tests with recirculated water from the zinc rougher tailing revealed that the presence of residual xanthate caused unintentional activation of copper minerals in the pre-float section. Copper recovery increased in the pre-flotation section and resulted in the loss of copper to the pre-float concentrate, which is considered as a tailing stream in the current flowsheet. Various types of activated carbon samples were tested to remove the residual xanthate from the tailing water. The carbon samples could be regenerated by heat treatment and reused for water treatment. Performance of the activated carbon samples was directly related to the pore size and surface area. Carbon-treated tailing water could be re-used in flotation without affecting the flotation performance

Effects of Residual Xanthate on Flotation Efficiency of a Cu-Zn Sulfide Ore

Reuse of process water in the flotation of sulfide ores has crucial importance for environmental sustainability and improved process economy. However, the chemistry of process water may be a critical subject for the flotation efficiency as the dissolved ion concentration increases with water reuse. In this study, the effects of water reuse on the flotation efficiency of a Cu-Zn sulfide ore were investigated. The flotation flowsheet consists of a pre-flotation section to remove the naturally floatable talc particles, and sequential copper and zinc flotation sections. Calcium, sulfate, thiosulfate, and xanthate were found as major contaminating ionic species in the process water discharged from flotation circuits. The flotation tests with recirculated water from the zinc rougher tailing revealed that the presence of residual xanthate caused unintentional activation of copper minerals in the pre-float section. Copper recovery increased in the pre-flotation section and resulted in the loss of copper to the pre-float concentrate, which is considered as a tailing stream in the current flowsheet. Various types of activated carbon samples were tested to remove the residual xanthate from the tailing water. The carbon samples could be regenerated by heat treatment and reused for water treatment. Performance of the activated carbon samples was directly related to the pore size and surface area. Carbon-treated tailing water could be re-used in flotation without affecting the flotation performance

Photochemical and antioxidant responses in the leaves of xerophyta viscosa Baker and digitaria sanguinalis L. under water deficit

Scopu

Are the Photosynthetic Performance Indexes and the Drought Factor Index Satisfactory Selection Criterion For Stress?

WOS: 000367698800016This study was conducted to assess the drought stress and the recovery responses of twenty one chickpea cultivars (Cicer arietinum L.) grown in Turkey. 20-day-old seedlings were subjected to mild drought conditions for 7 days, recovery period of 3 days followed. Then a moderate stress period of 10 days was applied, followed by recovery period of 4 days. Finally, severe stress period of 13 days was applied, followed by recovery period of 5 days. Drought stress treatments were observed to have an adverse effect on photosynthetic efficiency, but also malondialdehyde, total chlorophyll (app. half of cultivars) and carotenoid contents of leaf tissue have increased when compared with their controls. 21 chickpea cultivars were classified into four groups; highly tolerant, tolerant, less tolerant and sensitive, according to the drought factor index (DFI), the values calculated by photosynthetic performance index (PItotal). Only four cultivars recovered from severe drought stress conditions. Aziziye and Diyar 95 cultivars may be suggested to be cultivated in drought-prone areas. In general, the present results indicate that: 1. PItotal and DFI are very satisfactory selection criterion for drought stress. 2. The recovery processes of plants exposed to environmental constraints should be investigated to make the right selection.Hacettepe University, Foundation of Scientific ResearchesHacettepe University [801601007]This research was supported by Hacettepe University, Foundation of Scientific Researches (Project Number: 801601007). The authors would like to thank to Dr. A. Oukarroum (University of Quebec) for reviewing the manuscript and native speaker Huseyin D. Akarli for checking language

p.Ser348Cys mutation in FGFR3 gene leads to "Mild ACH /Severe HCH" phenotype

Achondroplasia (ACH) and hypochondroplasia (HCH) are genetic bone disorders known to be caused by gain-of-function mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. Both conditions share radiographic and phenotypical features. HCH is a milder form of ACH. Most individuals with ACH have the recurrent mutation (p.Gly380Arg) in the transmembrane (TM) domain of the receptor and individuals with HCH show the common mutation (p.Asn540Lys) in the tyrosine kinase 1 (TK1) region. Other rare mutations have been reported, however no additional hot-spot has been identified. We report an 8-month-old infant, with the heterozygous mutation, c.1043C > G, leading to an amino acid change from serine at 348 to cysteine (p.Ser348Cys). Clinical diagnosis of the patient is intertwined with "mild ACH" or "severe HCH". He did not demonstrate acanthosis nigricans (AN). This mutation has been reported in two different patients and it is located in the Ig-III domain of the FGFR3 region near other mutations associated with ACH. Among the two the 8-year old one also demonstrated AN without evindece of hyperinsulinem. This report emphasizes the benefit of whole gene sequencing for FGFR3 in individuals with suspected "mild ACH/severe HCH". This child will be monitored for future occurrence of AN

Some Growth And Chlorophyll Fluorescence Parameters Of Black And Hybrid Poplar Clones Under Water Stress

The effects of water stress on some growth and chlorophyll a fluorescence parameters were investigated in two native black poplar (Populus nigra L.) clones (Kocabey and Gazi) and in two hybrid poplar (Populus x euramericana (Dode) Guinier) clones (I-214 and I-45/51) to determine which among the four clones is the best adapted to water-stress conditions. The potted seedlings were grown under three watering regimes. As a result of the applied watering regimes, the predawn water potential (psi(pd)) of seedlings was maintained at about -0.3, -0.9, and -1.6 MPa in control, moderate, and severe water-stress treatments during the experiment, respectively. Drought treatment had significant effects on the morphology and growth characteristics of the clones but had generally insignificant effects on survival and the photochemical activity of photosystem II (PSII). Results obtained from the present study demonstrate that I-214 was the most successful in terms of its higher root/shoot ratio (R-s), maximum fluorescence yield (F-m), maximum quantum efficiency of PSII (F-v/F-m) values, and lower number of leaves among the examined four poplar clones under drought stress conditions. Consequently, the I-214 poplar clone may have the potential to be used in drought areas.WoSScopu

EVALUATION OF MALE INBRED LINES OF SUNFLOWER (Helianthus annuus L.) FOR RESISTANCE TO DROUGHT VIA CHLOROPHYLL FLUORESCENCE

Kaya, Yalcin/0000-0002-9297-8633WOS: 000392043000001Sunflower (Helianthus annuus L.) suffers from terminal drought accompanying with high temperature stress since it grows mainly in rain fed areas. Therefore, plant breeders try to improve more drought tolerant varieties and to screen their genetic materials for drought resistance. The present study was conducted to determine drought tolerance levels of sunflower male inbred lines developed by Trakya Agricultural Research Institute (TART), Edirne, Turkey. Inbred lines grown under controlled environmental conditions were sorted by polyphasic chlorophyll a fluorescence measurements. Drought stress applications were performed at three sunflower growth stages as R-3 (vegetative), R5-1 (head formation) and R-6 (milky seed). Based on applied different JIP-Test (analysis of O-J-I-P fluorescence transient) parameters such as Drought Factor index (-DFI) and Damage index (-DI), 70352 R, 8129 R, 0536 R and 9947 R restorer lines were found more drought tolerant than those of the other examined sunflower inbred lines, whereas TT 317 R and TT 199 R were determined as more drought sensitive than others. The drought tolerant inbred lines will be helpful to improve drought resistance in sunflower breeding programs.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [1001-113O926]This study was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under the Project 1001-113O926

Assessing drought tolerance in field-grown sunflower hybrids by chlorophyll fluorescence kinetics

Kaya, Yalcin/0000-0002-9297-8633WOS: 000475748200005Drought is one of the most damaging abiotic stress factors commonly experienced by plants, resulting in a significant loss of crop yield worldwide. The aim of the study was to assess drought tolerance of sunflower (Helianthus annuus) hybrids and find out potentially underlying photobiological traits. Experiment was conducted in the agricultural field of Eastern Mediterranean Agricultural Research Institute in Adana. To evaluate the drought tolerance of twenty-six sunflower hybrids polyphasic chlorophyll fluorescence measurements were performed at the three growth stages named as vegetative, head formation and milky seed (stress 1, S1; stress 2, S2; stress 3, S3, respectively). The hybrids were classified from drought tolerant to drought sensitive based on their drought factor index (DFI) values calculated from photosynthetic performance index. 9444 A X 9947 R and 9444 A X 8129 R were determined as the most tolerant hybrids, whereas 2453 A X 8129 R and 7751 A X TT 135 R were determined as the most sensitive hybrids. Severe drought stress (S2) inhibited severely both the donor and the acceptor sides of photosystem II in sensitive hybrids. Photosynthetic structures of drought-tolerant hybrids were less damaged by drought stress, consequently these hybrids could maintain their photosynthetic performances (minor changes in phi(Po), psi(o), delta(Ro), specific and/or phenomenological energy fluxes) approximately control levels under severe drought condition. As a result, results, 9444 A X 9947 R and 9444 A X 8129 R hybrids could be recommended to be used in the breeding programs and further studies as genetic material and to be grown in drought-prone areas.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [1001- 113O926]This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK, Project Number: 1001- 113O926)