Physiological Responses of Purple Passion Fruit (Passiflora Edulis Sims F. Edulis) Plants to Deficiencies of the Macronutrients, Fe, Mn, and Zn during Vegetative Growth

ABSTRACT

The purple passion fruit (Passiflora edulis Sims f. edulis) is a promising crop in Colombia because of its high potential for international markets and high profitability. However, without adequate fertilization, the metabolic processes of plant growth can be affected. The objective of this research was to evaluate the effect of macro- and micronutrient deficiencies on growth, photosynthesis, and transpiration in purple passion fruit plants during vegetative development. Seedlings with four to six leaves (three-months-old) were transplanted to a sand culture and subjected to mineral deficiencies using the missing element technique under greenhouse conditions. The plants subjected to Fe deficiency had the lowest maximum photosynthetic rate at saturation by light (1.72 µmol CO₂ m⁻²s⁻¹) at 72 days after treatment, while the lowest apparent quantum efficiency (0.008 µmol CO₂ µmol photons⁻¹) was observed in the plants with Mg deficiency. The lowest values of maximum photochemical efficiency of photosystem II, Fv/Fm (0.69) and transpiration rate (2.39 µg H₂O cm⁻²s⁻¹) were found in the plants with P deficiency. The mineral nutrient deficiencies negatively affected metabolic processes in the purple passion fruit plants, with the highest impact on photosynthesis observed with the Fe or Mg deficiencies. The plants subjected to P deficiencies were the most affected plants in terms of transpiration rate.

KEYWORDS:

• Leaf area
• chlorophyll a fluorescence
• leaf number
• photosynthesis
• transpiration

Acknowledgments

The authors thank COLCIENCIAS (Colombia) for funding this research through the project “Ecophysiology, mineral nutrition and integrated management of pests and diseases in avocado, banana passion fruit, purple passion fruit, and tomato tree plants, oriented towards their agronomic management, as raw material for the development of products of commercial interest”, National Network for bioprospecting RIFRUTBIO, contract 459/2013, guided by Dr. L.M. Melgarejo. The authors also thank the Departamento de Biología and Facultad de Ciencias Agrarias, Universidad Nacional de Colombia, Bogotá. The authors greatly acknowledge the financial support provided by the COLCIENCIAS and CEIBA foundation to develop this research as a part of the graduate study of Mrs. Tatiana Cárdenas and Mr. Edwin Torres.