Estimation of the net photosynthetic rate for waterlogged winter wheat based on digital image technology

Abstract

The net photosynthetic rate (Pn) is one of the important indicators to measure photosynthetic capacity of crops. Therefore, it is critically important to find real-time methods for accurately estimating Pn of winter wheat (Triticum aestivum L.). This information could provide guidance on the management of waterlogging stress. To explore the optimal monitoring method for Pn of winter wheat under waterlogging stress, the correlations between Pn and 16 characteristic image indices were analyzed in irrigated and drained microplot experiments. Then, based on the indices values, Pn was estimated using the multiple linear regression (MLR), support vector machine (SVM), backpropagation neural network (BP), and random forest (RF) models, which were constructed based on the optimal monitoring image indices. Water logging when compared to no waterlogged wheat had similar Pn values <6 days.After 12 days, waterlogged wheat plants had a lower Pn value than in no waterlogged plants. All indices were correlated with the Pn (p < 0.05), and Pn estimation accuracy was lower at the winter wheat flowering and complete ripeness periods than at the milky and waxy ripe maturity periods. Based on the results of the models tested, the RF model had higher R 2 (0.904) values than the other models. These findings suggest that machine learning models could be used to accurately predict Pn, and the random forest algorithm was the best.

Photosynthetic and Physiological Responses to Combined Drought and Low–Temperature Stress in Poa annua Seedlings from Different Provenances

“…When plants are subjected to abiotic stress, their photosynthetic gas exchange parameters are also affected. The photosynthetic rate can reflect the assimilation capacity of plants per unit leaf area and is an essential indicator for measuring plant photosynthetic capacity [56]. Our study proved that the Pn, Gs, Tr, and WUE of Poa annua seedlings from four provenances were significantly inhibited under stress, which was consistent with previous studies on rapeseed (Brassica napus L.) under combined drought and cold stress [57].…”

Photosynthetic adaptation mechanisms of waterlogged wheat (Triticum aestivum) at flowering under exogenous nitric oxide donor application

“…The existing literature have extensively summarized the potential mechanisms that contribute to this phenomenon, including physical change in soil (i.e., soil compaction, oxygen depletion, CO 2 accumulation, and low diffusion coefficient for gases), chemical changes in soil (i.e., ion toxicity, secondary metabolite toxicity, low redox potential, and declined soil pH ), biological changes in soil (i.e., low mineralization rate, low aerobic microbial activity, and low immobilization rate) and low growth rate and poor metabolic capability of all organs in plants (Hossain and Uddin, 2011; Arduini et al, 2016; Herzog et al, 2016; Manik et al, 2019; Kaur et al, 2020; de S. Nóia Júnior et al, 2023). From the perspective of plant growth and metabolic processes, the primary impact of waterlogging on wheat plants is the insufficient supply of assimilates due to reduced photosynthetic production capacity during waterlogging (Cotrozzi et al, 2021; Ma et al, 2022a; Olorunwa et al, 2022; Li et al, 2023; Liu et al, 2023).…”