Study of the effects of photoselective shades on growth quality, nutrient absorption and biochemical indices of Polianthes (Polianthes tuberosa L.)

The intensification of abiotic stresses, particularly drought and elevated temperatures driven by climate change, requires the widespread adoption of protected cultivation. A pivotal innovation within this system is the use of spectral-selective filters, which modify the solar spectrum to provide environmental protection and direct physiological control over plant growth, especially for high-value ornamental species. The application of colored shade nets in this study, positively influenced nutrient uptake and growth parameters except for stem diameter, spike length, number of flowers and plant and flower dry mass in Polianthes cut flowers. The highest concentration of potassium (2.78%), nitrogen (2.02%), and phosphorus (0.14%) was found in the green and blue shade treatments, but there was no significant difference between the treatments. Furthermore, the most substantial improvement in flower diameter was observed under the green shade net, resulting in a 20.75% increase, while the white shade net showed the smallest enhancement at 9.66% in comparison with full sunlight. Additionally, peroxidase activity and photosynthetic pigment levels were elevated in plants under green and white shading compared to those under blue nets. Proline content was significantly reduced by all colored shade treatments, with the highest accumulation observed in plants exposed to full sunlight. In conclusion, although the use of all shade nets improved some flower quality indices and somewhat increased the potassium, chlorophyll, and carotenoids contents and reduced proline in the plant, overall, the use of green shades is recommended.