to evaluate the effect of various levels of nitrogen fertilizer on nitrogen use efficiency and grain yield of canola cultivars, a split plot experiment based on randomized complete block design was conducted in 2007. factors were: nitrogen fertilizer at four levels (zero, 50, 100 and 150 kg/ha) in the main plots and canola cultivars at three levels (‘clover’, ‘opera’ and ‘okape’) in the sub plo...

Plant development is amazingly plastic — for example, identical pine seeds can give rise to a majestic tree in a forest or a scraggly bush on a rocky cliff. How is plant growth and development regulated so as to be capable of achieving such dramatically different endpoints? One factor that has emerged as a key regulator of plant form is gibberellin (GA; see Figure 1 inset for the chemical struc...

Key planting factors that influence corn stand establishment includes uniform depth and spacing of seed, correct seed population and optimizing the soil environment for rapid germination and uniform emergence. Other variables affecting stand establishment are seedbed quality (including soil moisture and temperature), seed quality and planter speed. Differences among fields for stand establishme...

Drought, a period of abnormally dry weather, results in soil-water deficit and subsequently plant-water deficit. The lack ofwater in the environment constitutes a stresswhen it induces an injury in the plant. Water deficit in the plant disrupts many cellular and whole plant functions, having a negative impact on plant growth and reproduction. Crop yields are reduced by 69% on average when plant...

Improved crop varieties are needed to sustain the food supply, to fi ght climate changes, water scarcity, temperature increase and a high variability of rainfalls. Variability of drought and increase in soil salinity have negative effects on plant growth and abiotic stresses seriously threaten sustainable agricultural production. To overcome the infl uence of abiotic stresses, new tolerant plan...

Autophagy is a conserved mechanism for the degradation of cellular contents in order to recycle nutrients or break down damaged or toxic material. This occurs by the uptake of cytoplasmic constituents into the vacuole, where they are degraded by vacuolar hydrolases. In plants, autophagy has been known for some time to be important for nutrient remobilization during sugar and nitrogen starvation...

Complementary biochemical and genetic approaches are being used to dissect the signaling network that regulates the innate immune response in plants. Receptor-mediated recognition of invading pathogens triggers a signal amplification loop that is based on synergistic interactions between nitric oxide, reactive oxygen intermediates and salicylic acid. Alternative resistance mechanisms in Arabido...

Plant hormones play an important role in plant response to abiotic stresses, by both stimulation of defence pathways and regulation of plant growth and development. The key hormone in the response to stresses associated with dehydration is abscisic acid (ABA). Its levels were followed during the response to salinity or drought in two species differing in their stress tolerance – radish and toba...

The endoplasmic reticulum (ER) is the major source of molecules that directly interact with the cell’s external environment. This occurs through the secretory pathway, which starts from the ER and regulates macromolecular traffic to the cell surface and inner hydrolytic compartments. It is thus no wonder that the ER functions as a major, very efficient station that integrates signaling from the...