Rana Nadeem Abbas

Lead toxicity in rice: effects, mechanisms, and mitigation strategies—a mini review

Lead (Pb) is a major environmental pollutant that affects plant morpho-physiological and biochemical attributes. Its higher levels in the environment are not only toxic to human beings but also harmful for plants and soil microbes. We have reviewed the uptake, translocation, and accumulation mechanisms of Pb and its toxic effects on germination, growth, yield, nutrient relation, photosynthesis, respiration, oxidative damage, and antioxidant defense system of rice. Lead toxicity hampers rice germination, root/shoot length, growth, and final yield. It reduces nutrient uptake through roots, disrupts chloroplastic ultrastructure and cell membrane permeability, induces alterations in leaves respiratory activities, produces reactive oxygen species (ROS), and triggers some enzyme and non-enzymatic antioxidants (as defense to oxidative damage). In the end, biochar amendments and phytoremediation technologies have been proposed as soil remediation approaches for Pb tainted soils.

Allelopathic effects of aqueous and organic fractions of Euphorbia dracunculoides Lam. on germination and seedling growth of chickpea and wheat

Se requiere la identificacion de especies de malezas con potencial alelopatico y la caracterizacion de sus efectos adversos en contra de los cultivos asociados para una mejor comprension de las interacciones cultivos-malezas. Se investigo la actividad fitotoxica de Euphorbia dracunculoides Lam. en la germinacion y crecimiento de plantulas de garbanzo (Cicer arietinum L.) y trigo (Triticum aestivum L.) bajo condiciones controladas. Dos estudios separados se realizaron con cada una de las cuatro fracciones de disolventes organicos (n-hexano, cloroformo, acetato de etilo, 1-butanol) y extracto acuoso (1:10 y 1:20) de fracciones enteras de plantas de E. dracunculoides usando agua destilada y 0,05% (v/v) dimetil sulfoxido (DMSO) como control. Diferentes fracciones acuosas y organicas de E. dracunculoides tuvieron una incidencia significativa en los atributos de germinacion y crecimiento de las plantulas de las especies evaluadas. El porcentaje de germinacion final de trigo no se vio afectado, sin embargo, la elongacion de raices y brotes y la acumulacion de biomasa en estas partes fueron significativamente retrasadas. La fraccion acuosa fue mas itotoxica que las fracciones organicas y disminuyo la germinacion de garbanzo en 53% y 35% para 1:10 y 1:20, respectivamente. Estas fracciones acuosas, 1:10 y 1:20, tambien redujeron la longitud de raices (75-64% y 33-34%) y brotes (62-18% y 21-21%) y el peso seco de raices (32-33% y 42-46%) y brotes (32-7% y 8480%) para trigo y garbanzo, respectivamente. Entre las fracciones organicas, n-hexano fue la mas supresora de las especies ensayadas. El analisis cromatograico detecto la presencia de cuatro itotoxinas en la fraccion acuosa (1:10) de la planta: acido furoico, acido p-cumarico, acido cafeico, y acido siringico. El estudio determino que E. dracunculoides es alelopatica sobre el trigo y el garbanzo.

Germination ecology of Ambrosia artemisiifolia L. and Ambrosia trifida L. biotypes suspected of glyphosate resistance

The germination ecology of Ambrosia artemisiifolia and A. trifida glyphosate susceptible biotypes sampled in marginal areas, was compared with that of the same species but different biotypes suspected of glyphosate resistance, common and giant ragweed, respectively. The suspected resistant biotypes were sampled in Roundup Ready® soybean fields. Within each weed species, the seeds of the biotype sampled in marginal area were significantly bigger and heavier than those of the biotype sampled in the soybean fields. A. artemisiifolia biotypes exhibited a similar dormancy and germination, while differences between A. trifida biotypes were observed. A. artemisiifolia biotypes showed similar threshold temperature for germination, whereas, the threshold temperature of the susceptible A. trifida biotype was half as compared to that of the resistant A. trifida biotype. No significant differences in emergence as a function of sowing depth were observed between susceptible A. artemisiifolia and suspected resistant A. trifida biotype, while at a six-cm seedling depth the emergence of the A. artemisiifolia susceptible biotype was 2.5 times higher than that of the A. trifida suspected resistant biotype. This study identified important differences in seed germination between herbicide resistant and susceptible biotypes and relates this information to the ecology of species adapted to Roundup Ready® fields. Information obtained in this study supports sustainable management strategies, with continued use of glyphosate as a possibility.

Spatio-temporal reconciliation to lessen losses in yield and quality of forage soybean (Glycine max L.) in soybean-sorghum intercropping systems

Bragantia, Campinas, v. 77, n. 2, p.283-291, 2018 ABSTRACT: Soybean suffers a serious blow to forage yield and quality while in intercropping with cereal forages like sorghum. The aim of this field investigation was to optimize planting time and spatial arrangement for boosting yield, quality and profitability of intercropped soybean. Treatments included soybean sown 20 days before and after sorghum under different spatial arrangements (3-1, 1-3, 2-3, 3-2 and 3-3 row proportions). The factorial arrangement was used to employ randomized complete block design (RCBD) for experimental execution with four replicates. Soybean sown 20 days prior to sorghum in 2-3 row replacement series was effective in yielding the highest yield attributes of soybean, which led to the highest green forage yield and dry matter biomass. The same intercropping system proved to be superior in generating the highest net income and benefit-cost ratio (BCR) (4.31). CROP PRODUCTION AND MANAGEMENT Article