Practical Applications In Agriculture Research Articles

Acetyl salicylic acid (Aspirin) and salicylic acid induce multiple stress tolerance in bean and tomato plants

The hypothesis that physiologically activeconcentrations of salicylic acid (SA) and itsderivatives can confer stress tolerance in plants wasevaluated using bean (Phaseolus vulgaris L.) andtomato (Lycopersicon esculentum L.). Plantsgrown from seeds imbibed in aqueous solutions (0.1--0.5 mM) of salicylic acid or acetyl salicylic acid(ASA) displayed enhanced tolerance to heat, chillingand drought stresses. Seedlings acquired similarstress tolerance when SA or ASA treatments wereapplied as soil drenches. The fact that seedimbibition with SA or ASA confers stress tolerance inplants is more consistent with a signaling role ofthese molecules, leading to the expression oftolerance rather than a direct effect. Induction ofmultiple stress tolerance in plants by exogenousapplication of SA and its derivatives may have asignificant practical application in agriculture,horticulture and forestry.

Brassinosteroids.

It was in 1979 when GROVE et al. isolated from pollen of rape (Brassica napus) a highly active plant growth promoter, named it brassinolide and elucidated its structure as (22R,23R,24S)-2α,3α, 22,23-tetrahydroxy-24-methyl-B-homo-6a-oxa-5α-cholestan-6-one (1) by spectroscopic methods including X-ray analysis (1). The original structural features of this compound and its unique high biological activity at very low concentrations stimulated intense research activities in many laboratories. Such efforts were directed towards the search for similar compounds in the plant kingdom, their chemical synthesis, biochemistry and biological mode of action leading up to their practical application in agriculture and horticulture. As a result of this interdisciplinary and rapidly processing research, brassinosteroids can nowadays be regarded as a new class of plant hormones with ubiquitous occurrence in the plant kingdom. Especially, recent molecular biological studies demonstrated their essential role for normal plant growth and development. A series of reviews have been published (2–11). Whereas the first book on brassinosteroid research covers developments up to 1990 (12), two up-to-date publications about this topic have appeared very recently (13, 14). The present article covers the literature up to December 1998 with special consideration of phytochemical, analytical and biochemical aspects.KeywordsImmature SeedPhalaris CanariensisFagopyrum EsculentumSide Chain HydroxylationBrassinosteroid BiosynthesisThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

The current status of physiology and biochemistry of brassinosteroids

Brassinolide, first isolated from pollen of rape as a plant growth promoting substance, has been found to be widely distributed in the plant kingdom. Over thirty endogenous analogues, called collectively brassinosteroids, have been isolated and identified. As a new class of plant hormones, brassinosteroids show not only growth promoting activity but also other physiological effects on the growth and development of plants and draw attention as promising chemicals for practical application in agriculture. This review describes the current status of the studies on the natural occurrence, analysis, physiological actions, metabolism and biosynthesis of brassinosteroids.

Parameterized Model of Gramineous Crop Growth: II. Within‐Season Simulation Calibration

AbstractThe accuracy of parameterized crop growth models is dependent on obtaining the proper parameter values that control the response of the model to environmental conditions. In this study, a method is described for objectively evaluating model parameters based on observations of crop growth obtained during the growing season. An iterative numerical procedure is used to systematically manipulate the values of selected parameters and initial conditions until the model simulation matches the observations of growth. Examples involving a previously‐developed growth model indicate that reasonably accurate simulations can be made for three gramineous crops (grain sorghum, corn, and spring wheat) by calibrating a set of parameters and initial conditions that affect leaf area appearance and senescence. It is proposed that the effectiveness of this procedure in using infrequent growth observations and the ability to obtain these observations using nondestructive measurement techniques make this modelling procedure feasible for use in practical agricultural applications.