Nitrogen in Flowers

This chapter explores the literature and research on nitrogen in flowers. An overview of nitrogen deficiency symptoms in some flowers, i.e., Curcuma alismatifolia (ornamental curcuma), Tagetes erecta (marigold), Zinnia violacea (zinnia), and Gomphrena globose (gomphrena) were presented. Additionally, nitrogen uptake, translocation, and application in some flowers, i.e., ornamental curcuma, narcissus, orchids, and rose, were discussed in this chapter. Nitrogen affects the life cycle of flower, including vegetative and reproductive phases. Flower size, stem length, number of flowers per plant, and color were reduced by nitrogen deficiency. Therefore, the optimum level of nitrogen supply in each growth stage is important for flower crop production

Effects of Using Plasma-Activated Water as a Nitrate Source on the Growth and Nutritional Quality of Hydroponically Grown Green Oak Lettuces

Nitrate is a major source of the inorganic nitrogen taken up by the roots of plants. Nitrate sources are generally derived from inorganic minerals by an energy-consuming chemical process; as a result, the price of chemical fertilizers is gradually increasing year by year. NO3-N, generated from N2 using the plasma technique, is an alternative method of producing nitrate from the air. Therefore, in this research, we aimed to determine the efficiency of generating NO3-N using plasma-activated water (PAW) to replace nitrates from chemical fertilizer in a nutrient solution. Green oak lettuce (Lactuca sativa L.) was grown in a hydroponics system using the double-pot technique. The plants were supplied with three different nutrient solutions (based on Hoagland’s solution), i.e., T1, no nitrate in the nutrient solution (NO3− = 0); T2, using nitrate sourced from a commercial chemical fertilizer (normal nitrate); and T3, using a nitrate source generated using the pinhole plasma jet technique (plasma nitrate). The other macronutrients and micronutrients in each treatment were equally supplied. The results show that, at the harvested stage (21 days after the plants received treatment), the no-nitrate (T1) treatment provided lower growth and yields. Moreover, compared with the normal nitrate (T2) and plasma nitrate (T3), the results indicate that most growth and yields showed no statistical differences. In terms of nitrate accumulation within plants, it was found that the normal nitrate treatment (T2) had the highest levels of nitrate accumulation, in both the underground and aboveground parts of green oak lettuce. These results confirmed that plasma nitrate could be an alternative source of nitrate N which provided a safer way for the environment and human health in terms of nitrate accumulation. In addition, data related to the chemical analysis of free amino acid concentrations in each treatment are discussed in this research

Irrigation Levels and Fertilization Rates as Pre-Harvest Factors Affecting the Growth and Quality of <i>Hippeastrum</i>

Growing Hippeastrum in an open field or a greenhouse requires precision irrigation and fertilizer to promote plant growth and development. Therefore, this research aimed to study the effect of irrigation level combined with fertilization rate on the growth and development of Hippeastrum. Two experiments were carried out to determine the influence of irrigation and fertilizer on the growth, flowering, and bulb quality of Hippeastrum. In the first experiment, bulbs of Hippeastrum ‘Red Lion’ with circumferences of 25 cm were grown in plastic plots using mixed soil as growing media under a 50% shading net. Plants were irrigated daily until drainage and water contained in macropores by gravity action (Field capacity: FC) for 90 days after planting (DAP) and supplied with three different 15N-15P2O5-15K2O fertilization rates, i.e., 0, 2.5, and 5 g per pot. Plant growth and water use efficiency were measured at 45, 60, and 90 DAP. The results showed that plants supplied with 0 g of fertilizer had the lowest plant height and number of leaves per plant at 90 DAP, whereas there was no significant effect of fertilizer rate treatments on flower quality. The water use efficiency, evapotranspiration rate (ET), crop evapotranspiration under standard condition (ETc), crop coefficient (Kc), photosynthetic rate, and stomatal conductance were decreased when plants were supplied with fertilizer at a rate of 0 g per pot at 90 DAP. In the second experiment, plants were irrigated with four levels, i.e., 100, 75, 50, and 25% ETc combined with three fertilization rates, i.e., 0, 2.5, and 5 g per pot. At 180 DAP, the results showed that water deficit treatment (50 and 25% ETc) decreased plant growth and bulb quality. Irrigation with 100% ETc combined with 2.5 or 5 g per pot and irrigation with 75% ETc combined with 5 g per pot were the optimum levels to promote plant growth and bulb quality in Hippeastrum

Nitrogen Uptake and Translocation in Vanda Orchid after Roots and Leaves Application of Different Forms 15N Tracer

Vanda is an economically important orchid that is widely produced in Thailand. Usually, growers apply large amounts of fertilizer throughout the plant, covering the leaves and roots to ensure good quality products. Nitrogen fertilizer, in terms of ammonium (NH4+) and nitrate (NO3&minus;), is generally used as an N source. In addition, nitrogen organic fertilizer (glutamine) is increasingly being used to promote rapid growth in some plants. However, the absorption efficiency of organic N compared with the inorganic form (NH4+ and NO3&minus;) via the roots or leaves of Vanda has not been evaluated. Therefore, this research aimed to compare the fate of organic N (in glutamine form) and inorganic N in Vanda using a 15N tracer. Vanda &lsquo;Patchara Delight&rsquo; was grown in a plastic greenhouse under a 50% shading net at an average temperature of 25 &deg;C and 80% relative humidity (RH). The plants were sprayed weekly via roots or leaves with 100 mL of 15N solution, 2.5 mM 15NO3&minus; + 2.5 mM NH4+ (N1), 2.5 mM NO3&minus; + 2.5 mM 15NH4+ (N2), and 2.5 mM glutamine (15N2)(N3) for 4 weeks. The plants were then sampled and separated into leaves and roots, and 15N abundance was analyzed using an elemental analyzer coupled with an isotope-ratio mass spectrometer or IRMS. The plants that received only glutamine via roots showed the highest 15N use efficiency (15NUE) of about 28.19% at 30 days after the first feeding (DAF), whereas 15NH4+ resulted in the lowest 15NUE among 15N sources. Regardless of the application site, plants supplied with 15NH4+ showed a lower labeled N concentration and labeled N content in stems and leaves than those fed with a combination of 15NO3&minus; or a sole application of 15N-glutamine. The largest labeled N concentrations in stems, leaves and roots were found in plants supplied with sole glutamine via roots. At 30 DAF, 15N solution either combined with 15NO3&minus; or solitary 15N-glutamine did not affect the labeled N concentration in leaves. Therefore, supplying organic N in glutamine form to Vanda can provide a 4&ndash;7% higher NUE than inorganic N, especially when supplying the solution to the roots