Nutrimental requirements of heliophytic poinsettias have not yet been determined, this information is essential for developing an adequate technological package to orient producers in its management. The behavior of t...Nutrimental requirements of heliophytic poinsettias have not yet been determined, this information is essential for developing an adequate technological package to orient producers in its management. The behavior of the plant under nutritional stress needs to be known by the application of a hydroponic system. The objective of the present work was to evaluate the physiological effect of induced deficiencies of five macronutriments （nitrogen, phosphorous, potassium, calcium, and magnesium） and its influence on the pigment production of the poinsettia Euphorbia puleherrima cv. ＂Valenciana＂. The study was made during 2010 at the Research Unit ＂Dr. Ramon Fernandez Gonzalez＂ in Texcoco, State of Mexico. Six treatments were tested during 240 days from transplant in a totally randomized experimental design. Chlorophylls contents were determined at the beginning of the experiment. At the end of the treatment period, the contents of nutrients, chlorophylls, leaf carotenoids and bract anthocyanins were determined. The effects observed as results of the treatments were： reduction in plant height and diameter; the lowest content of total chlorophylls was observed in the absence of nitrogen, the largest reduction being of chlorophyll a and carotenoids; a low content of anthocyanins was observed to be associated with low nitrogen and calcium; a high correlation was found between nitrogen supplementation and measured non-destructively with a SPAD 502 Minolta unit values measured intensity of green color of leaves.展开更多
文摘Nutrimental requirements of heliophytic poinsettias have not yet been determined, this information is essential for developing an adequate technological package to orient producers in its management. The behavior of the plant under nutritional stress needs to be known by the application of a hydroponic system. The objective of the present work was to evaluate the physiological effect of induced deficiencies of five macronutriments （nitrogen, phosphorous, potassium, calcium, and magnesium） and its influence on the pigment production of the poinsettia Euphorbia puleherrima cv. ＂Valenciana＂. The study was made during 2010 at the Research Unit ＂Dr. Ramon Fernandez Gonzalez＂ in Texcoco, State of Mexico. Six treatments were tested during 240 days from transplant in a totally randomized experimental design. Chlorophylls contents were determined at the beginning of the experiment. At the end of the treatment period, the contents of nutrients, chlorophylls, leaf carotenoids and bract anthocyanins were determined. The effects observed as results of the treatments were： reduction in plant height and diameter; the lowest content of total chlorophylls was observed in the absence of nitrogen, the largest reduction being of chlorophyll a and carotenoids; a low content of anthocyanins was observed to be associated with low nitrogen and calcium; a high correlation was found between nitrogen supplementation and measured non-destructively with a SPAD 502 Minolta unit values measured intensity of green color of leaves.
