Physiological Responses of Robinia pseudoacacia and Quercus acutissima Seedlings to Repeated Drought-Rewatering Under Different Planting Methods.

Xiao Liu,Meixia Song,Peixian Fan,Kening Cui,Ning Du,Qinyuan Zhang,Hui Wang,Renqing Wang,Ning Wang,Pan Wu,Peiming Zheng

doi:10.3389/fpls.2021.760510

Abstract

Changing precipitation patterns have aggravated the existing uneven water distribution, leading to the alternation of drought and rewatering. Based on this variation, we studied species, namely, Robinia pseudoacacia and Quercus acutissima, with different root forms and water regulation strategy to determine physiological responses to repeated drought-rewatering under different planting methods. Growth, physiological, and hydraulic traits were measured using pure and mixed planting seedlings that were subjected to drought, repeated drought-rewatering (i.e., treatments), and well-irrigated seedlings (i.e., control). Drought had negative effects on plant functional traits, such as significantly decreased xylem water potential (Ψmd), net photosynthetic rate (AP), and then height and basal diameter growth were slowed down, while plant species could form stress imprint and adopt compensatory mechanism after repeated drought-rewatering. Mixed planting of the two tree species prolonged the desiccation time during drought, slowed down Ψmd and AP decreasing, and after rewatering, plant functional traits could recover faster than pure planting. Our results demonstrate that repeated drought-rewatering could make plant species form stress imprint and adopt compensatory mechanism, while mixed planting could weaken the inhibition of drought and finally improve the overall drought resistance; this mechanism may provide a theoretical basis for afforestation and vegetation restoration in the warm temperate zone under rising uneven spatiotemporal water distribution.

Highlights

Precipitation patterns have been substantially altered as a consequence of global climate change, the frequency and intensity of precipitation increase, but the total amount decreases (Easterling et al, 2000; Högy et al, 2013; Gimbel et al, 2015; Ge et al, 2017)
Xylem midday water potential of pure planting was measured using one of the seedlings in each plot; md of mixed planting was estimated by measuring leaf water potential in a pressure chamber (1505D-EXP, PMS Instrument Company, Albany, OR, United States); before measurement, leaves were covered with aluminum foil for 1 h to allow leaf water potential
Different water availability had significant effects on plant hydraulic traits (Figure 1 and Table 2); this may result from the different relative positions of the two tree species on the “isohydric-anisohydric” continuous spectrum, that is, R. pseudoacacia is closer to anisohydric plant, and its hydraulic traits respond quickly with the change of water availability, while Q. acutissima is closer to the isohydric plant, and its hydraulic traits respond slowly with the change of water availability (Moser et al, 2016; Li et al, 2019, 2020; Liu et al, 2020)

Summary

Introduction

Precipitation patterns have been substantially altered as a consequence of global climate change, the frequency and intensity of precipitation increase, but the total amount decreases (Easterling et al, 2000; Högy et al, 2013; Gimbel et al, 2015; Ge et al, 2017). This phenomenon has aggravated the existing spatiotemporal uneven water distribution in the warm temperate zone (Luan et al, 2011; Corlett, 2016), leading to the alternation of drought and rewatering. In the warm temperate zone, which is the main strategy for plant species to respond to the repeated drought-rewatering?

Methods

Results

Conclusion