Phosphorus Stress-Induced Differential Growth,and Phosphorus Acquisition and Use Efficiency by Spring Wheat Cultivars

ABSTRACT

Phosphorus (P) is a finite, non-renewable, and natural resource and a vital major nutrient for plant metabolic and developmental processes. However, adverse soil biogeochemical characteristics of alkaline-calcareous soils (especially Aridisols) and highly weathered acid soils (i.e., Ultisols and Oxisols) render orthophosphate (Pi) as the least available major nutrient due to P complexation, sorption, and/or fixation. In such soil environments, plant bioavailable P is only a small fraction of total soil P, seriously limiting crop growth and production. Different plant species, and even cultivars of the same species, may display a suite of growth responses that enable them to solubilize and scavenge soil P either by enhancing external Pi acquisition or reprioritizing internal Pi use under P-stress soil environments. This paper reports relative growth responses, P acquisition and P-use efficiency characteristics by 14 cultivars of spring wheat (Triticum aestivum L.) grown in solution culture with high/low P supply induced by applying soluble NH₄H₂PO₄, sparingly soluble rock phosphate, and Ca₃(PO₄)₂. The wheat cultivars exhibited considerable genetic diversity in biomass accumulation, P concentrations, P contents, factor (PSF) and P efficiency characteristics [i.e., P utilization efficiency (PUE), P efficiency (PE), and PE ratio (PER)]. Plant growth and PE parameters were significantly correlated, while P uptake was linearly related with biomass increase and solution pH decrease. The wheat cultivars with high PUE, PER and P uptake, and low PSF, and plant P concentration were more efficient in utilizing P and, hence, more tolerant under P-stress environment. Biomass and P contents of “P efficient/low-P tolerant” wheat cultivars were superior to “P inefficient/low-P sensitive” cultivars at all P-stress levels. Hence, “P efficient/low-P tolerant” cultivars are the most desirable wheat genotypes for P-stress environments because they are able to scavenge more P from sparingly soluble P sources or soil-bound P forms.     

Yield stability of induced-early-maturing mutants of mungbean (Vigna radiata) and their use in a multiple-cropping system

The performance of seven mutants of mungbean along with parental types was studied at 41 different sites in three summer crop seasons from 1980 to 1982. The performance of mutants was also studied in spring in the fallow period preceding cotton, and in early summer in the fallow period between wheat harvest and rice/maize planting, to assess their suitability of growing as a catch-crop in these fallows.

The mutants yielded significantly higher and matured 2–4 weeks earlier than parental types, leaving sufficient time to sow the succeeding crops. The mutants were characteristically short-statured, and superior to their parents with respect to number of pods per plant, seed weight, harvest index and productivity per day, but similar in numbers of seeds per pod and seed protein content.

The stability of yield was estimated through regression analysis. Significant genotypic differences were observed among mutants and varieties. Some mutants were widely adapted whereas others performed better in favourable environments. The parental types tended to respond well under poor environments.

Owing to their higher yield potential, early and uniform maturity, and wide adaptability, four mutants were approved as commercial varieties in 1986. These mutants yield 30–50% higher than the parents, mature in 55–70 days, and are suited to both summer and spring crop seasons. Of these four mutants, two can be grown in the fallow period between wheat harvest and rice/maize planting. Because of their determinate plant type, non-shattering pod and top fruit-bearing habit, these mutants are also amenable to intercropping practices and mechanised harvesting operations.

The role of induced mutations for the improvement of mungbean is discussed.     

Selenium supplementation reduced oxidative stress in diethylnitrosamine-induced hepatocellular carcinoma in rats

Selenium in the form of sodium selenite (SSE) is an essential micronutrient which known to possess antioxidant and anticancer properties. This study emphasizes the role of selenium on oxidative stress in experimental rats with N-diethylnitrosamine (DEN) initiated and 2-acetylaminofluorene (2-AAF) promoted multistage hepatocellular carcinogenesis (HCC). Rats were divided randomly into six groups: negative control, positive control (DEN+2-AAF), preventive group (pre-SEE 4 weeks+DEN), preventive control (respective control for preventive group), therapeutic group (DEN+post-SSE 12 weeks) and therapeutic control (respective control for therapeutic group). SSE (4 mg L(-1)) was given to animals before initiation and during promotion phase of HCC. The levels of total protein (TP), conjugated diens (CD), malondialdehyde (MDA), fluorescent pigment (FP), antioxidant activity (AOA) and DNA damage were measured. Supplementation of SSE before the initiation phase of carcinogenicity significantly increased TP and AOA level (p < 0.05) while it decreased the levels of CD, MDA, DNA damage and FP (p < 0.05). Supplementation of SSE during the promotion phase of carcinogenicity significantly decreased the DNA damage and FP level (p < 0.05) and there were negative correlation between the level of AOA and with the level of FP and CD. Thus, supplementation of SSE reduced the adverse changes which occur in liver cancer. However, the chemoprevention effect of SSE was more pronounced when it was supplemented before initiation phase of cancer when compared to promotion phase.     

Different Eucalyptus Species Show Different Mechanisms of Tolerance to Salinity and Salinity × Hypoxia

ABSTRACT

We studied the effect of sodium chloride (NaCl) salinity and oxygen deficiency stress on growth and leaf ionic composition of three Eucalyptus species [E. tereticornis, E. camaldulensis (Silverton), and E. camaldulensis (Local)]. Species were grown with control (no NaCl) and salinity (150 mol m^?3 NaCl) under hypoxic and non-hypoxic conditions in nutrient solution with five replications following CRD. Species differed significantly in their response to salinity and hypoxia. Absolute shoot dry matter was significantly better in E. camaldulensis (Silverton) in salinity and in E. camaldulensis (Local) in saline hypoxic treatment. E. tereticornis was the most sensitive species to salinity and salinity × hypoxia in the root environment. Sodium (Na⁺) and chloride (Cl^?) concentrations were significantly lower in E. camaldulensis (Local) in non-hypoxic saline treatment compared to the other two species. E. camaldulensis (Silverton) seems to have better tissue compartmentalization, whereas E. camaldulensis (local) seems to have better exclusion of Na⁺ at the root level.     

INTERACTIVE EFFECT OF SULFUR AND PHOSPHORUS ON NODULATION,NITROGEN FIXATION,AND NUTRIENT UPTAKE BY CHICKPEA GROWN ON CALCAREOUS SOILS IN PAKISTAN

Field experiments were conducted at two different locations under rainfed conditions of Punjab, Pakistan to assess nodulation, nitrogen fixation and nutrient uptake by chickpea (Cicer arietinum L.) in response to application of three rates [0, 40, and 80 kg phosphorus pentoxide (P₂O₅ ha^?1)] of phosphorus and three rates (0, 15 and 30 kg S ha^?1) of sulfur in different combinations. Effect of phosphorus application was nonsignificant while that of sulfur was significant on percent nitrogen derived from atmosphere. Both phosphorus and sulfur application resulted in increase in nitrogen fixation up to 38% and 33% over control, respectively. Nutrient uptake [nitrogen (N), phosphorus (P), and sulfur (S)] increased significantly with the application of phosphorus and sulfur and correlated positively with nitrogen fixation. There is direct involvement of sulfur in the process of nitrogen fixation whereas effect of phosphorus on nitrogen fixation is indirect mainly through enhanced growth and dry matter production.     

Impact of tillage and intra-row spacing on cotton yield and quality in wheat–cotton system

Farmers normally practice conventional tillage ((CT), disk plowing, cultivator, rotavator, and leveling) in cotton (Gossypium hirsutum L.) with 15 cm intra-row spacing to avoid risks of poor plant stand and obtain higher yield. However, CT is costly besides it has adverse effects on soil and crop when sown after wheat. Conservation tillage [zero tillage (ZT) or reduced tillage (RT)] with suitable spacing can reduce production cost, increase cotton yield and quality, and it has favorable effects on soil properties. Field experiments were conducted to evaluate cotton response to tillage (ZT, RT, and CT) and intra-row spacing (15.0, 22.5, 30.0, 37.5 cm). Results revealed that RT produced higher bolls plant^?1, boll weight, seed cotton yield, ginning out turn, fiber length and strength than ZT and CT. Mean boll weight, seed cotton yield, earliness, and fiber qualities were optimum at 22.5 cm spacing. Tillage × spacing interaction showed optimum boll weight, earliness, and fiber strength with 15.0–22.5 cm spacing under RT. CT with 22.5 cm spacing also performed better in terms of boll weight and fiber strength; however, 15.0 cm spacing resulted in earlier maturity. RT with 22.5 cm spacing is an alternative to CT for higher yield, earliness, and quality of cotton besides environmental safety.     

Investigating the effect of Azospirillum brasilense and Rhizobium pisi on agronomic traits of wheat (Triticum aestivum L.)

ABSTRACT

Plant growth-promoting rhizobacteria (PGPR) play an important role in improving crop growth but have not been studied sufficiently. A wire house experiment was conducted in Pakistan to determine the combined effect of inoculating wheat seeds with PGPR on the subsequent growth and yield of the wheat. The experiment included four treatments: T_{0 –} no-inoculation (control), T₁ – Azospirillum brasilense inoculation, T₂ – Rhizobium pisi inoculation and T₃ – co-inoculation with A. brasilense and R. pisi. Development and growth attributes, as well as final yield of wheat, were studied. Co-inoculation of seeds with both strains increased significantly wheat grain yield, the number of grains per plant and 1000-grain weight by 36%, 11% and 17%, respectively, compared to non-inoculated control. While crop growth rate increased for, respectively, 5.5% and 33% at tillering and flag leaf stages, corresponding values for T₃ were about 9% and 14% higher than values for sole inoculations in T₁ and T₂. Co-inoculation also significantly increased leaf epicuticular wax and relative water content as compared to the control treatment. Thus, inoculation of wheat seeds with A. brasilense and R. pisi and their combination is a promising method to improve growth, yield and quality of wheat.     

Asociacion Latinoamericana de Especialistas en Las Ciencias Aplicadas a Las Malezas (ALAM)

Abstract

ENTOMOGENOUS NEMATODES, A MANUAL AND HOST LIST OF INSECT-NEMATODE ASSOCIATIONS. G. O. Poinar, Jr. E. J. Brill, Leiden, 175. ISBN 90 04 04240 7. Pp. 317. Price Dutch Guilders 96.

PESTICIDE INDEX. Fifth edition. Edited by W. J. Wiswesser. Entomological Society of America, 1976. Pp. 328. Price US $12.00.

ENVIRONMENTAL DYNAMICS OF PESTICIDES. Edited by Rizwanul Haque and V. H. Freed. Plenum Press, New York and London, 1975. ISBN 0 306 36306 2. Pp. viii + 387. Price £15.65.

TOXICOLOGY OF INSECTICIDES. Fumio Matsumura. Plenum Press, New York and London, 1975. ISBN 0 306 30787 1. Pp. xvii + 503. Price £14.60.

CROP PRODUCTION PRINCIPLES AND PRACTICES. S. R. Chapman and L. P. Carter. W. H. Freeman &; Co., San Francisco, USA and Reading, England, 1976. ISBN 0–7167–0581–8. Pp. 566. Price £9.50.

DISEASES OF TROPICAL AND SUBTROPICAL FRUITS AND NUTS. A. A. Cook. Hafner Press, New York, 1975. Pp. 317. Price US $20.00.

MORE DEMATIACEOUS HYPHOMYCETES. M. B. Ellis. Commonwealth Mycological Institute, Kew, Surrey, 1976. ISBN 0 85 198 365 0. Pp. 507. Price £15.00 in UK, £18.00 overseas.

AN ANNOTATED BIBLIOGRAPHY OF COLOUR ILLUSTRATED MINERAL DEFICIENCY SYMPTOMS IN TROPICAL CROPS. Technical Communication No. 34 of the Commonwealth Bureau of Horticulture and Plantation Crops. J. B. D. Robinson. Commonwealth Agricultural Bureaux, Farnham Royal, UK, 1974. ISBN 0 85198 304 9. Pp. 84. Price £5.00 UK, £6.00 overseas. First Supplement, 1976. Price £1.50 UK, £1.80 overseas.

NUTRITION IN PREVENTIVE MEDICINE. WHO Monograph Series, No. 62. G. H. Beaton and J. M. Bengoa. WHO, Geneva, 1976. ISBN 92 4 140062 5. Pp. 590. Price Sw. fr. 83.

ECONOMICALLY APPROPRIATE TECHNOLOGIES FOR DEVELOPING COUNTRIES: AN ANNOTATED BIBLIOGRAPHY. M. Carr. Intermediate Technology Publications Ltd., London, 1976. ISBN 0 903031 19 1. Pp. 101. Price: £2.00 net; £2.25 UK post paid; £3.15 airmail; £2.30 surface mail.

CHINESE CHAIN AND WASHER PUMPS. S. Watt. Intermediate Technology Publications Ltd., London, 1976. ISBN 0 90301 26 4. Pp. 49. Price: £0.95 net; £1.15 UK post paid; £1.65 airmail; £1.25 surface mail.

A MANUAL ON BUILDING MAINTENANCE – Volume 1: Management and Volume 2: Methods. D. Miles. Intermediate Technology Publications Ltd., London, 1976. ISBN 0 903031 28 0. Vol. 1 pp. 78, Vol. 2. pp. 64. Price for each volume: £1.25 net; £1.50 UK post paid; £2.20 airmail; £1.55 surface mail.

AGRICULTURAL RESEARCH FOR DEVELOPMENT. THE NAMULONGE CONTRIBUTION. Edited by M. H. Arnold. Cambridge University Press, 1976. Pp. xi + 353. ISBN 0 521 21051 8. Price £13.00.

SURVEY OF THE WORLD'S APHIDS. V. F. Eastop and D. Hille Ris Lambers. Dr W. Junk B.V., The Hague, 1976. ISBN 90 6193 561 X. Pp. 573. Price Dutch Guilders 160.

CONTROLLED-DROPLET APPLICATION AND U.L.V. SPRAYING. Anon. BP Ltd., London, 1976. Pp. 28. Price: free. Available from: Agricultural Branch, International Marketing Department, BP Trading Ltd, Britannic House, Moor Lane, London EC2Y 9BU, UK.

ANNUAL REVIEW OF PHYTOPATHOLOGY, Volume 14, 1976. Edited by K. F. Baker, G. A. Zentmyer and E. B. Cowling. Annual Reviews Inc., Palo Alto, California, USA. ISBN 0 8243 1314 3. Pp. 511. Price US $17.00 (USA), US £17.50 (elsewhere).

INTEGRATED PEST MANAGEMENT. Edited by J. Lawrence Apple and Ray F. Smith. Plenum Press, New York. 1976. ISBN 0 306 30929 7. Pp. 200. Price US $48.50.

INSECTICIDE BIOCHEMISTRY AND PHYSIOLOGY. Edited by C. F. Wilkinson. Plenum Press, New York and London, 1976. ISBN 0 306 30872 X. Pp. 768. US $59.40 (UK £31.19).     

Antifeedant and toxic effects of naturally occurring and synthetic quinones to the cabbage looper, Trichoplusia ni

We investigated the feeding deterrent effects and toxicity of naturally occurring and synthetic quinones to the cabbage looper, Trichoplusia ni. Feeding deterrent effects were determined via a leaf disc choice bioassay. Based on DC₅₀ values, 1,4-naphthoquinone was the most active antifeedant (DC₅₀ = 1.8 μg/cm²) followed by juglone (DC₅₀ = 2.1 μg/cm²), 2-methoxy-1,4-naphthoquinone (DC₅₀ = 2.6 μg/cm²), plumbagin (DC₅₀ = 3.3 μg/cm²), and 2,3-dimethoxy-5-mehtyl-1,4-benzoquinone (DC₅₀ = 4.2 μg/cm²) in third instar cabbage looper larvae. 2-Bromo-1,4-naphthoquinone, 2-chloro-3-morpholino-1,4-naphthoquinone, 1,8-dihydroxy-anthraquinone, 2-methyl-1,4-naphthoquinone and naphthazarin had DC₅₀ values ranging from 8.4 to 10.1 μg/cm². Juglone and plumbagin were able to provide protection to intact cabbage plants in a greenhouse experiment. Cabbage looper larvae consumed less leaf area and weighed less on cabbage plants treated with either of these naturally occurring quinones. Most of the quinones demonstrated levels of antifeedant activity greater than neem, a positive control, in laboratory bioassays. The level of activity for juglone was comparable to neem in the greenhouse experiment. There was also a reduction in the number of larvae on treated plants compared with the negative control. Structure-activity relationships suggest that the antifeedant effects of the tested quinones depend on the number and position of hydroxyl and methoxyl substituents of quinones. Most of the quinones were of medium-low toxicity to third instar cabbage looper larvae via topical administration. Some of these quinones could have potential for development as commercial insect control agents targeting the feeding behavior of insects with minimal toxicity, provided that their impacts on non-target organisms and environment are minimal.