Growth stage-based response of wheat (Triticum aestivum L.) to kinetin under water-deficit environment: pigments and gas exchange attributes

Plant growth regulator, kinetin, is known to modulate the key physiological processes under abiotic stresses in different crops. However, kinetin-mediated response at different growth stages of crop plants is lagging behind. Therefore, a field experiment was conducted to appraise the potential role of exogenously applied kinetin in alleviating the effects of water scarcity on wheat. Three levels of kinetin (0, 75, and 150 mg/L) were used either as seed treatment or foliar spray at the vegetative or the post-anthesis stage. Water deficit markedly reduced shoot fresh mass, plant chlorophyll level, flag leaf photosynthesis, stomatal conductance, and transpiration rate. Degradation of chlorophyll a was greater in plants subjected to post-anthesis water-deficit conditions. However, plants growing under continuous water-deficit conditions had significantly lower concentration of chlorophyll b than those treated with water scarcity at the post-anthesis stage or receiving normal irrigation. Inhibited photosynthesis of wheat in response to post-anthesis water-deficit conditions was largely due to non-stomatal factors. In contrast, stomatal factors were the main constraints for photosynthesis in plants growing under continuous scarcity of water. Plants subjected to continuous water starvation had markedly lower grain yield than those subjected to water-deficit conditions at post-anthesis stage. Application of kinetin before seed sowing or at the post-anthesis stage significantly reduced the negative effects of drought on flag leaf chlorophyll and stomatal conductance. Lower level of kinetin (75 mg/L) was found to be more effective in mitigating the inhibitory effects of water shortage on photosynthesis and growth, and improved grain yield under water scarcity.     

Assessment of variation in drought tolerance using some key physiological criteria in potential wheat (Triticum aestivum L.) cultivars of different geographic origins

The present experiment comprised seven wheat cultivars, two drought levels (0 and 17% PEG-8000) and four replicates. The seeds of six wheat cultivars (Al-lugaimi, Bonus, Kronos, Yecora-rojo, Irena and Sama) were supplied by the King Saud University, Riyaz, Saudi Arabia, whereas S-24 was obtained from the Department of Botany, University of Agriculture, Faisalabad. The seeds were allowed to germinate and grow for 20 days in medium having full-strength Hoagland's nutrient solution or Hoagland's solution with 17% PEG-8000. For the appraisal of drought tolerance, various physiological traits such as gas-exchange attributes (A, E, C_i, g_s , and A/E), leaf water relations (ψ_w, ψ_s and ψ_p) and the activities of key antioxidant enzymes (SOD, POD and CAT) were determined. On the basis of biomass and gas-exchange attributes (A, E, and g_s ), cultivars Al-lugaimi and Sama were found to be drought tolerant, cultivars Yecora-rojo and Irena moderately drought tolerant, and cultivars S-24, Bonus and Kronos drought sensitive. However, plant osmotic adjustment and the activities of potential antioxidant enzymes (SOD, POD and CAT) were not found to be associated with drought tolerance of the different wheat cultivars.     

Morphological and molecular evaluation of Turkish rice (Oryza sativa L.) landraces

Genetic Resources and Crop Evolution - This study was carried out to evaluate Turkish rice landraces, in 2016 and 2017. Twenty-nine morphological traits were used for morphological evolution and 10...     

Physiological effects of psyllid (Paratrioza cockerelli) on potato

Feeding by psyllid nymphs causes “Psyllid yellows,” a characteristic yellowing of shoots which results in a dramatic loss of tuber yield. If psyllid infestation is not controlled, the onset of shoot yellowing and growth reductions can occur within two weeks. When insecticides are applied after yellowing, recovery of plants often is not complete. In this study comparisons were made of the physiology and growth of tops and tubers of recovered and permanently injured potatoes of the cultivars ‘Denali,’ ‘Kennebec,’ and ‘Norgold Russet.’ Permanently injured plants senesced rapidly, developed less shoot growth, aerial tubers and shortened and thickened internodes. They had lower tuber yields than plants that recovered. Permanently injured ‘Denali’ developed shoots on old flowering stems. In permanently injured plants of all cultivars, the tubers were small and badly misshapen but numbers increased. In recovered ‘Kennebec’ plants tubers were also misshapen, but were of average size. Tubers of recovered ‘Denali’ and ‘Norgold Russet’ were of acceptable shape. In samplings made during tuber growth, dry weight percentages of total soluble sugars, sucrose and glucose of tubers from permanently injured plants were found to be the same as those of recovered plants. In all cultivars, starch percentages of tubers from permanently injured plants were higher than that of the recovered, but the pattern of carbohydrate content changes was similar for permanently injured and recovered cultivars.     

Use of 1,6-diaminohexane-functionalized glycidyl methacrylate-g-poly(ethylene terephthalate) fiber for removal of acidic dye from aqueous solution

In this study, removal of Congo red (CR) from aqueous solution by 1,6-diaminohexane-functionalized glycidyl methacrylate-g-poly(ethylene terephthalate) (HMDA-GMA-g-PET) fiber was investigated. A new aminated fibrous adsorbent was prepared by a reaction between amine and epoxy group in GMA-g-PET fiber prepared by grafting GMA monomer onto poly (ethylene terephthalate) (PET) fiber. Effects of various parameters such as pH, treatment time, initial, dye concentration, and reaction temperature on the adsorption amount of dye onto reactive fiber were investigated. The adsorption rates of CR were much higher on the HMDA-GMA-g-PET fiber than on GMA-g-PET and ungrafted PET fiber. The effective pH was 2.0 for adsorption on grafted PET fiber. It was found that the sufficient time to attain equilibrium was 60 min. The maximum adsorption capacity of the reactive fiber for CR is 16.6 mg/g fiber. The rates of adsorption were found to conform to the pseudo-second order kinetics with good correlation. It was found that the adsorption isotherm of CR fitted Freundlich type isotherm.     

Preliminary studies on two Diaspididae (Hemiptera) species feeding on Johnsongrass (<Emphasis Type="BoldItalic">Sorghum halepense</Emphasis>) in Turkey

The scale insects Acanthomytilus sacchari (Hall) and Duplachionaspis erianthi Borchsenius (Hemiptera, Diaspididae) are newly recorded as indigenous insects from Turkey. Both A. sacchari and D. erianthi were found to feed only on rhizomes of Johnsongrass. A field study was conducted to determine host ranges and feeding effects of these scale insects on Johnsongrass, Sorghum halepense (L.) Pers. No feeding of these species was observed on Zea mays L. (maize), Sorghum sudanense Staph. (sorghum), Aegilops triuncialis L. (barbed goatgrass), Avena fatua L. (wild oat), A. sterilis (sterile oat), Bromus tectorum L. (downy brome), Cynodon dactylon (L.) Pers. (bermudagrass), Phragmites australis (Cav.) Trin. ex Steudel (common reed), Poa bulbosa L. (bulbous bluegrass), or Secale montanum Guss. (wild rye). The mean infestation rates of the scale insects on Johnsongrass in southeastern Anatolia were 11.47% and 1.64% for A. sacchari and D. erianthi, respectively. Further investigations are required to clarify their biology and damage to Johnsongrass under field conditions.     

Effect of exogenous application of free polyamines on physiological disorders and yield of ‘Kaleh-Ghoochi’ pistachio shoots (Pistacia vera L.)

Pistachio trees exhibit some physiological disorders such as abscission of inflorescence buds, fruit abscission, the production of blank, non-split, early-split and deformed nuts. Since the occurrence of these disorders is closely related to the yield, the effect of free polyamine treatments on these disorders and the yield was investigated in two consecutive years (“on” and “off” years). Free polyamine treatments were applied one week before and also two weeks after full bloom. Results showed that Spermine (Spm), unlike Putrescine (Put), decreased the physiological disorders of pistachio and also increased the yield. Free polyamine treatments did not affect the percentage of early-split nuts. Spermidine (Spd) decreased the percentage of both fruit abscission and deformed nuts but did not affect the yield. In both the “on” and “off” years the effect of Spm and Spd was greatly dependent on both the time of application and the concentrations used. Results of free polyamine analysis showed that exogenous application of these compounds, especially two weeks after full bloom, increased the free polyamine contents of shoots in both “on” and “off” years confirming the absorption of free polyamines via spray application in pistachio crop. Exogenous application of Spm two weeks after full bloom decreased the abscission of inflorescence buds in “on” year supporting the idea that free polyamines could trigger the abscission process of inflorescence buds. Since Spm decreased the percentage of blank, non-split and deformed nuts, it seems that Spm dominantly plays a key role in the growth and development of pistachio nuts.     

Low cost microbioassay test for assessing cytopathological and physiological responses of ciliate model Paramecium caudatum to carbofuran pesticide

One of the major changes that have occurred over the past few years is the re-examination of conventional methods and the global demand for innovative low cost bioassay tests for assessing water quality, toxicity evaluation and bioremediation. In the present study acute toxicity, physiological and cytotoxic impact of carbofuran to a commonly occurring fresh water ciliate was measured. Intrinsic cytotoxicity was evident on macro nuclear apparatus that exhibited deformities such as fragmentation, deep incision, vacuolization and degenerative macronucleus. Depletion in the food vacuole formation of Paramecia was evident. Changes in the pulsatory vacuole activity of Paramecium caudatum, highlighted dose dependent response by the test compound. The simplicity of handling this ciliate makes unicellular eukaryote, an alternative organism for the toxicity assessment of pollutants. The tests carried in this study are simple and fast, a bioassay that gives overall information about the physiological and cytotoxic effects of carbofuran to P. caudatum. Such bioassay tests using ciliates are more suitable for risk assessment of water quality, early detection of water pollution and possible role of ciliates as bioindicators and strategic tools in the bioremediation of water bodies.     

Effect of thiamine injection on growth performance,hematology and germinal vesicle migration in sterlet sturgeon Acipenser ruthenus L.

The present study aimed to investigate the effect of thiamine on growth, hematological, egg thiamine content and oocyte nucleus migration indices in sterlet sturgeon (Acipenser ruthenus). A total of 45 female fish (698.6 ± 8.9 g) were distributed in nine fiberglass tanks with three treatments (each in three replicates). Experimental fish were fed once a day with practical diet supplemented with 1 g kg^?1 amprolium hydrochloride (as the antithiamine) for 5 months before spawning. Thiamine hydrochloride was injected to fish with one of three doses at 0, 5 and 50 mg kg^?1 body weight (BW) at three different stages. At the end of each month, fish were weighed and growth parameters such as weight gain, specific growth rate, feed efficiency and final weight were determined. At the end of the 5-month period, hematological parameters and egg thiamine content were measured. The results showed no significant differences in terms of growth performance. Hemoglobin, number of red blood cells and white blood cells were not significantly different among the treatments, but hematocrit was significantly higher in fish injected with 5 mg kg^?1 BW thiamine. The mean corpuscular volume and mean corpuscular hemoglobin were not significantly different, but lower value of mean corpuscular hemoglobin concentration was observed in fish injected with 5 mg thiamine. Percentage of lymphocytes, neutrophils, eosinophils and monocytes were not significantly different among treatments. The results of the germinal vesicle migration index at different stages showed no significant differences in different groups. Results showed that free thiamine, thiamine pyrophosphate and total thiamine in eggs significantly increased at 50 mg kg^?1 injection dose compared with the control, but no significant different was found in thiamine monophosphate. The results revealed that thiamine injection to sterlet broodstocks has positive accumulation in egg thiamine content and some hematological parameters but have no effect on growth and ovarian maturation. We conclude that thiamine can affect some physiological features of broodstock, which needs to be specified in further studies.