Some stresses experienced by plants during growth improve internal quality, yet in the latest production systems plant stresses are the first thing to be eliminated! And we are quick to breed new varieties that have greater resistance to abiotic and biotic stress, that grow better and faster, that have favourable external characteristics for the grower, the logistics chain, retailer and consumer.
It would appear that in the latest high-tech production systems scientists should be looking for what stresses at what levels are positive, and when to apply them, in the interests of internal quality, even specific nutrients, rather than optimal production parameters in the interests just of yield and external appearance.
Research in Italy (University of Naples Federico II) and in Cyprus (Agricultural Research Institute, Nicosia) has demonstrated that moderate salinity and mineral stresses can elicit metabolic processes that result in the increased synthesis of health promoting substances in tomatoes. Frontiers in Plant Science. For other research with Spinach, see: Acta Hortic. 1099, 407-412 DOI: 10.17660/ActaHortic.2015.1099.47
It is also well-known that applying techniques of deficit irrigation at specific periods of growth can improve production quality in various crops from grapes (sugar content) to container grown Poinsettia. Regulated deficit irrigation for crop production under drought stress. A review.
More food crops are being routinely tested for nutritional quality and safety aspects but how is this information conveyed to the consumer and used by growers to compare the effects of stresses (or no stresses) on internal quality with different production techniques and innovations that include: precision agriculture, closed production systems and urban towers, recycling, robotic handling and positioning of plants and products, synthetic biology, faster and greater production through modified photosynthesis?
In food crops, there is a conspicuous absence of comparative information concerning the effect of optimal growing conditions on nutritional quality and there is controversy concerning tests that claim that nutritional quality of food crops, particularly fruit and vegetables, has notably declined over the last 70 years (pp 59/60 ‘Silicon Solutions’, E. Bent, Sestante Edizioni 2014).
Routine measurement of internal produce quality represents an increasingly important feature of agricultural innovation in terms of production, promotion and consumer choice. This is of particular relevance to production near landfill sites that have been heavily contaminated. While biological production gives the consumer some measure of security regarding the non-use of agro-chemicals, is the nutritional quality of biologically grown crops superior? See Hortcom theme ‘Silicon in Agriculture’ and article entitled ‘Dual use against Biotic and Abiotic Stress! a review by Dr. Achilea, NewAgInternational pp 40-47, Sept/Oct edition 2018 . For a scientific overview by Robin J. Marles, see: Mineral nutrient composition of vegetables, fruits and grains: The context of reports of apparent historical declines.
In ornamentals, internal quality refers to characteristics such as vase-life; for example a minimum sugar content in the buds is necessary for roses to flower properly. Physiological conditions (including the effects of stresses) during production affect yield and post-harvest quality. Finally, and rarely taken into account, there is the relative net contribution that cultivated plants make to the ecosystem.