Physiological and Biochemical Dynamics of Pinus massoniana Lamb. Seedlings under Extreme Drought Stress and during Recovery

Changchang Shao,Qing Lou,Xianying Luo,Honglang Duan,Guijie Ding,Yuanhong Fu

doi:10.3390/f13010065

Abstract

In recent years, global forests have been facing an increase in tree mortality owing to increasing droughts. However, the capacity for plants to adjust their physiology and biochemistry during extreme drought and subsequent recovery is still unclear. Here, we used 1.5-year-old Pinus massoniana Lamb. seedlings and simulated drought conditions to achieve three target stress levels (50%, 85%, and 100% loss of stem hydraulic conductivity (PLC)), followed by rehydration. Needle water status, gas exchange, and biochemical parameters were assessed during drought and recovery. The results showed that drought had significantly negative impacts on needle water status and gas exchange parameters, with gas exchange declining to 0 after PLC85 was achieved. Soluble protein concentration (SPC), soluble sugar concentration (SSC), malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, and needle water-use efficiency showed fluctuations. The activity of antioxidant enzymes and the values of osmotic regulators were then gradually decreased as the physiological and biochemical functions of seedlings were disturbed. Seedlings showed a stronger ability to recover from PLC50 than PLC85 and PLC100. We conclude that the physiological and biochemical recovery of P. massoniana seedlings is more likely to be inhibited when plants experience increasing drought stress that induces 85% and greater loss of hydraulic conductance.

Highlights

Accepted: 29 December 2021Drought is an important abiotic stress that has negative impacts on plant growth and survival and is associated with a series of physiological and biochemical processes [1].In recent decades, a decline in tree productivity and their increased mortality caused by drought have been observed in forests worldwide [2]
This study investigated the dynamics of gas exchange, antioxidant enzymes, and osmotic regulation in the development of, and recovery from, drought stress in P. massoniana seedlings
When PLC50 was achieved, Soil mass water content (SWC) and relative water content (RWC) values were reduced by about 66% and

Summary

Introduction

Accepted: 29 December 2021Drought is an important abiotic stress that has negative impacts on plant growth and survival and is associated with a series of physiological and biochemical processes [1].In recent decades, a decline in tree productivity and their increased mortality caused by drought have been observed in forests worldwide [2]. Drought is an important abiotic stress that has negative impacts on plant growth and survival and is associated with a series of physiological and biochemical processes [1]. In the context of climate change, the frequency and intensity of droughts are likely to increase in the future [3,4], which could further threaten tree survival [5]. Physiological and biochemical processes may play roles in regulating plant drought resistance. The question of whether physiological and biochemical processes will permit recovery from extreme drought remains unanswered. An in-depth study of plant physiological and biochemical responses to both drought and post-drought recovery is important for accurately predicting plant responses and resilience to drought under a changing climate

Methods

Results

Discussion

Conclusion