Transport patterns of foliar and root absorbed copper in bean seedlings

Abstract

Copper absorption by roots or leaf and transport to other parts were followed in 9‐days old bean (Phaseolus vulgaris L. cv. Vaghya) seedlings. Translocation was also measured in 4 cm segments of the stem. It was found that larger amount of Cu was retained in the roots and Cu was more mobile through phloem than through xylem, as indicated by the data on translocation from root and leaf. Bean plants were found to translocate more Cu to the stem than to other parts. Kinetic analysis of absorption by excised roots and stem segments revealed that the roots have a maximum uptake capacity and high affinity for Cu.     

Excretion of dibutyl phthalate by sorghum roots under Fe‐stress: Evidence of its action on chlorosis recovery

Sorghum (Sorghum bicolor L. Moench) cv. CSH‐7, an Fe‐efficient hybrid was grown and subjected to Fe‐deficiency stress. The nutrient medium was extracted for isolation of reductant chemicals. By means of thin layer chromatography, I.R. spectrum and HPLC analysis, dibutyl phthalate was identified as the principal component. This chemical was not found in the nutrient medium extracted before the onset of chlorosis or in that after the plants recovered from chlorosis. Furthermore, synthetic dibutyl phthalate and that obtained from the exudate when supplied to the nutrient medium caused greening of chlorotic sorghum in 24 hours. Evidence that the root medium of the Fe‐efficient sorghum can induce recovery of an Fe‐inefficient sorghum grown together, has also been obtained. It is concluded that dibutyl phthalate released by the Fe‐efficient sorghum subjected to stress, is responsible for making Fe available for utilisation. The mechanism of action of dibutyl phthalate on chlorosis recovery is still an open question.     

Identification of dibutyl phthalate in the root exudate of Fe‐efficient (corchorus capsularis L.) subjected to Fe‐deficiency stress : Its action on Fe‐chlorosis recovery

The jute (Corchorus capsularis L.) cv. 3RC‐212 which is Fe‐efficient, was subjected to Fe‐deficiency stress, and the nutrient medium was examined for chemicals, when the plants became chlorotic and the pH was lowered to about 4. While phenolic acids could not be detected, DBP (dibutyl phthalate) was identified in the extract by means of TLC and HPLC. The effect of DBP and caffeic acid was studied in JRC‐212 and DBP was found to cause recovery of the plants from chlorosis in 5 days. The chemicals, PA (phthalic acid), a derivative of DBP (50 mg/1) were supplied to chlorotic plants of JRO‐632, an Fe‐inefficient jute cultivar, and both the chemicals were effective in chlorosis recovery. PA application caused more rapid greening than DBP.

Jute is the second crop species in which DBP is identified in the root exudate. The detection of DBP was first recorded in sorghum CSH‐7.     

Absorption and transport of Na and Cl in rice cultivars differing in their tolerance to salinity: An examination of the effects of ammonium and potassium salts

The absorption and transport of Na and Cl from 0.1 mM and 10 mM ²²Na labelled NaCl or ³⁶Cl labelled KCl were examined in 15 days old seedlings of 3 cultivars of rice differing in their tolerance to salinity. Furthermore, the effects of 10, 100 and 1000 ppm (N)₂S on their uptake were studied. It was found that in general, the salt‐tolerant cultivars BR and PNL‐1 absorbed more Na and translocated a lesser proportion of it to the shoot, compared to the salt‐sensitive IR‐8, from 0.1 mM NaCl. The presence of (N)₂S reduced the uptake of Na in all the cultivars. It was also found that the presence of 100 ppm K, KN or NNreduced Na absorption from 0.1 mM NaCl significantly in all the cultivars, and the translocation to shoot in BR‐ Chloride transport from 0.1 mM NaCl was reduced by (N)₂S in all the cultivars. The 3 cultivars differed significantly in the rates of absorption and transport of Na and Cl. The results indicate that PNL‐1 which is a cross of IR‐8 X BR, has inherited the salt tolerance trait from BR. Lower rates of Na translocation to the shoot can be used as an index of salt tolerance in rice.     

Fe‐deficiency tolerance in papaya (Carica papaya L.): Ph reduction and chlorosis recovery in response to stress

The phenomenon of Fe‐stress response mechanism was examined using papaya as a test fruit plant species. This plant behaved like the many Fe‐efficient crop cultivars, reduced the pH of the minus Fe nutrient medium, followed by recovery from chlorosis. The response mechanism was observed in both the 2 cultivars, CO‐1 and CO‐3. Evidence obtained with this plant supports the widespread occurrence of the mechanism in diverse crop species ‐ grain, vegetable and fruit crop plants too.     

Effect of feeding of calcium hydroxide-treated or vitamin E-supplemented cottonseed meal on plasma gossypol levels, blood parameters, and performance of Bikaneri lambs

To study the effect of feeding calcium hydroxide-treated or vitamin E-supplemented cottonseed meal (CSM) incorporated diets on plasma gossypol, blood parameters and animal performance, 24 male Bikaneri lambs of 6–7 months of age and of uniform body weight were divided into four groups of six animals each in a completely randomized design and respectively fed isonitrogenous and isocaloric concentrate mixtures containing 20 % soybean meal (CON) or 40 % raw CSM (RCSM), 40 % raw CSM supplemented with 500 IU of vitamin E per head per day (ERCSM), and 40 %, 1.5 % calcium hydroxide-treated CSM (CaCSM) along with ad libitum wheat straw throughout 510 days of experimental feeding. The lambs on all the diets grew linearly throughout the experimental period. The total weight gain, in turn the average daily gain (ADG), was not affected by dietary variations. The daily intake of dry matter, crude protein (CP), digestible crude protein (DCP) and total digestible nutrients (TDN) were found comparable among lambs of all the groups. Though total gossypol intake was similar in RCSM, ECSM and CaCSM groups, however, free gossypol intake was significantly higher (P?<?0.01) in RCSM, ECSM groups as compared to CaCSM group. Serum iron and blood hemoglobin levels were significantly (P?<?0.05) lower in RCSM group as compared to CaCSM and CON groups, and ALT activity was significantly (P?<?0.05) higher on RCSM group as compared to other groups. Plasma gossypol and osmotic fragility of erythrocytes were significantly (P?<?0.05) increased in RCSM group as compared to CaCSM and ERCSM groups. However, there was no significant difference in the concentration of other blood/serum biochemical constituents among the lambs on different groups. Based on the results, it may be concluded that feeding of 40 % CSM in the concentrate mixture of the diet in Bikaneri lambs did not have any major adverse effect in blood parameters and animal performance. Either calcium hydroxide treatment or vitamin E supplementation did not produce any major additional benefits.     

Suicidal germination for parasitic weed control

Parasitic weeds of the genera Striga and Orobanche spp. cause severe yield losses in agriculture, especially in developing countries and the Mediterranean. Seeds of these weeds germinate by a chemical signal exuded by the roots of host plants. The radicle thus produced attaches to the root of the host plant, which can then supply nutrients to the parasite. There is an urgent need to control these weeds to ensure better agricultural production. The naturally occurring chemical signals are strigolactones (SLs), e.g. strigol and orobanchol. One option to control these weeds involves the use of SLs as suicidal germination agents, where germination takes place in the absence of a host. Owing to the lack of nutrients, the germinated seeds will die. The structure of natural SLs is too complex to allow multigram synthesis. Therefore, SL analogues are developed for this purpose. Examples are GR24 and Nijmegen‐1. In this paper, the SL analogues Nijmegen‐1 and Nijmegen‐1 Me were applied in the field as suicidal germination agents. Both SL analogues were formulated using an appropriate EC‐approved emulsifier (polyoxyethylene sorbitol hexaoleate) and applied to tobacco (Nicotiana tabacum L.) fields infested by Orobanche ramosa L. (hemp broomrape), following a strict protocol. Four out of 12 trials showed a reduction in broomrape of ≥95%, two trials were negative, two showed a moderate result, one was unclear and in three cases there was no Orobanche problem in the year of the trials. The trial plots were ca 2000 m²; half of that area was treated with stimulant emulsion, the other half was not treated. The optimal amount of stimulant was 6.25 g ha^?1. A preconditioning prior to the treatment was a prerequisite for a successful trial. In conclusion, the suicidal germination approach to reducing O. ramosa in tobacco fields using formulated SL analogues was successful. Two other options for weed control are discussed: deactivation of stimulants prior to action and biocontrol by Fusarium oxysporum. © 2016 Society of Chemical Industry     

Effect of biochar amendment on soil physical,chemical and biological properties and groundnut yield in rainfed Alfisol of semi-arid tropics

The aim of this study was to evaluate the effect of biochar and organic soil amendments on soil physicochemical and microbial load, carbon sequestration potential, nutrient uptake and yield of groundnut in acidic red soil under rainfed condition. Biochar was prepared from red gram, cotton, maize stalk and mesquite wood using pilot scale slow pyrolysis biochar unit. The above sources of biochar at the rate of 2.5 and 5 t ha^?1 and enriched farmyard manure 0.75 t ha^?1, composted coir pith 10 t ha^?1 and arbuscular mycorrhizae 100 kg ha^?1 were applied as basal with required nitrogen, phosphorous and potassium fertilizer. Biochar amendment at the rate of 5 t ha^?1 reduced the bulk density from 1.41 to 1.36 g cm^?3 and increased the soil moisture 2.5%. With respect to soil chemical changes, it raised soil pH from 5.7 to 6.3; increased the cation exchange capacity 1.4 cmol⁺ kg^?1 and enhanced the carbon buildup 4.4 t ha^?1. The significant differences in bacteria, fungi and actinomycetes population were observed between biochar and control. The nitrogen, phosphorous and potassium were better utilized under biochar and composted coir pith, which was 21, 5 and 20 kg ha^?1 higher than control. The experimental results suggested that application of biochar to acidic red soil favoured good soil physical, chemical and biological environment, and these positive changes influenced growth and yield attributes and enhanced pod yield 29% over control.     

Grain sorghum response and Palmer amaranth control with postemergence application of fluthiacet-methyl

Palmer amaranth is a problematic weed in grain sorghum production in central United States. Due to limited herbicide options available and ever increasing herbicide-resistant weed species, there is a demand for new mode-of-action herbicides for use in grain sorghum. Fluthiacet-methyl is a relatively new active ingredient that inhibits the enzyme protoporphyrinogen oxidase in target plants. Field studies were conducted at three sites in central United States in 2010 and 2011 to evaluate crop response and Palmer amaranth control with postemergence application of fluthiacet-methyl in grain sorghum. Treatments included fluthiacet-methyl at 4.8 and 7.2 g active ingredient (a.i.) ha^?1 alone and tank-mixed with 2,4-D amine at 260 g acid equivalent (a.e.) ha^?1 or atrazine at 840 g a.i. ha^?1. Carfentrazone at 8.8 g a.i. ha^?1, atrazine at 840 g ha^?1, and a non-treated control were also included. Fluthiacet-methyl treatments caused 9–38% crop injury at 4 ± 1 days after treatment. Tank-mixing atrazine with fluthiacet-methyl seldom affected crop injury, while mixing 2,4-D with fluthiacet-methyl often reduced crop injury. Generally, injury caused by fluthiacet-methyl alone or in combination with atrazine or 2,4-D disappeared within 3 weeks after treatment. Grain yields were reduced in one trial, when 2,4-D mixed with 4.8 or 7.2 g ha^?1 of fluthiacet-methyl caused 18% and 13% plant lodging and 24% and 14% grain yield loss, respectively. Across site-years, fluthiacet-methyl alone at 4.8 or 7.2 g ha^?1 provided 55–95% control of Palmer amaranth. Greater Palmer amaranth control (≥75%) with fluthiacet-methyl alone was achieved when weeds were small or density was low at the time of spraying. Tank-mixing atrazine with fluthiacet-methyl increased Palmer amaranth control and sorghum yields considerably. Tank-mixing 2,4-D with fluthiacet-methyl also increased Palmer amaranth control, but to lesser extent and less consistently than with atrazine. Results indicated that fluthiacet-methyl has potential for use in grain sorghum to combat weeds resistant to acetolactase synthase-inhibitors, triazines, and synthetic auxin herbicides. Tank-mixing atrazine or 2,4-D with fluthiacet-methyl is desirable for effective Palmer amaranth control.     

Antifungal activity of silver nanoparticles synthesized using turnip leaf extract (Brassica rapa L.) against wood rotting pathogens

The synthesis of metal nanoparticles using greener methodology and its application in biological fields is a burgeoning field of research. We demonstrated the synthesis of silver nanoparticles using turnip leaf extract and its interaction with wood-degrading fungal pathogens such as Gloeophyllum abietinum, G. trabeum, Chaetomium globosum, and Phanerochaete sordida. TEM images revealed that the silver nanoparticles were predominantly spherical and loosely agglomerated with an average size of 16.14 nm. DLS measurement of silver nanoparticles revealed an average hydrodynamic diameter of ca. 39.5 nm with a zeta potential of ?14.8 mV at pH 7.5. FTIR spectra revealed the presence of amine and aliphatic esters, which were involved in the reduction and stabilization of silver nanoparticles. The as-synthesized silver nanoparticles showed broad spectrum antifungal activity against wood-degrading fungi by inhibiting growth. Thus, the greener-synthesized silver nanoparticles can be used as an antifungal agent against wood-degrading fungal pathogens.