Assessment of photo-protection, photosynthetic efficiency and growth responses of cassava (Manihot esculenta Crantz) subjected to fluctuating actinic light condition

Abstract

Abstract Light intensity is a critical environmental factor that influences plant growth and development. Plants have evolved various protective mechanisms to survive high light conditions, including non-photochemical quenching (NPQ), which dissipates excess energy as heat to prevent photodamage. However, NPQ can limit effective photosynthetic yield when plants changeover to low light conditions. This phenomenon is scarcely studied in cassava, a starchy storage root crop of the tropics known for high biological efficiency and climate resilience. To address this knowledge gap, we conducted a study to assess the photo-protection ability and growth response of six cassava varieties exposed to natural environmental light conditions (control), as well as intermittent high light (IHL) conditions at 900 µmol m− 2 s− 1. Our results showed a significant effect of light treatment on above ground biomass, crop biomass, chlorophyll a and b, photosynthetic rate, and NPQ values when plants were subjected to low to high light and high to low light transition. Variety Sree Suvarna had the highest yield under both control and IHL conditions, with crop biomass of 4.31 kg plant− 1 and 4.11 kg plant− 1, respectively. Our findings suggest that screening the plants with the capacity to postpone photoinhibition and those with the potential for quick recovery from photoinhibition can improve the photosynthetic performance, which has implications for increasing the efficiency and resilience of cassava crops and increasing agricultural productivity sustainably.