Effects of defoliation modalities on plant growth, leaf traits, and carbohydrate allocation in Amorpha fruticosa L. and Robinia pseudoacacia L. seedlings

Abstract

& Key message Defoliation modality significantly affected leaf traits and carbon allocation especially in the early recovery period of two Leguminosae woody species. Robinia pseudoacacia L. recovered more quickly following defoliation than Amorpha fruticosa L. & Context Defoliation resulting from anthropogenic disturbance, insects, and grazing animals affects plant growth and vegetation dynamics. Robinia pseudoacacia L. and Amorpha fruticosa L. with different susceptibility to biotic attack are commonly used for vegetation restoration in North China. However, plant responses to defoliation were not fully understood in the two Leguminosae woody species. & Aims We selected R. pseudoacacia and A. fruticosa to determine the effects of defoliation on individual plant growth, leaf traits, and carbohydrate allocation and compared the two species in terms of recovery strategies following defoliation for vegetation restoration. & Methods In a greenhouse experiment, A. fruticosa and R. pseudoacacia seedlings were subjected to three defoliation treatments: defoliation of the top down (TD) or bottom up (BU) 50% of the crown, and a control without defoliation (CK). The physiological and growth traits of seedlings were determined at 1, 3, 14, 30, and 60 days following defoliation.

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

“…In contrast, the two tree species grew rapidly by increasing photosynthesis after rewatering, that is, they adopted the compensatory mechanism. R. pseudoacacia adopted an under compensatory mechanism or equal compensatory mechanism ( Figures 3A,B ), and Q. acutissima adopted an equal compensatory mechanism or even over compensatory mechanism ( Figures 3C,D ; Trlica and Rittenhouse, 1993 ; Pinkard et al, 2007 ; Quentin et al, 2012 ; Wang et al, 2020 ), to minimize the impact of drought.…”

“…Gas-exchange characteristics were measured between 9:00 and 11:00 on sunny days. During the measurement, temperature, relative humidity, and CO 2 concentration inside the chamber were controlled at 28°C, 50%, and 400 ppm, respectively ( Wang et al, 2020 ; Liu et al, 2021 ).…”

“…Robinia pseudoacacia L., shallow-rooted species with wide root crown width, and Quercus acutissima Carr., deep-rooted species with narrow root crown width, are dominant species in the tree layer of temperate deciduous broadleaved forests in Northern China. They are widely dispersed sympatric tree species in Northern China ( Wang and Zhou, 2000 ; Wang et al, 2020 ), and in recent research, they are renowned for their high drought tolerance and fast recovery capability in the warm temperate zone ( Xu et al, 2009 ; Du et al, 2017 ; Li et al, 2019 ; Wang et al, 2020 ). Moreover, on the “isohydric-anisohydric” continuous spectrum, R. pseudoacacia is an anisohydric species, while Q. acutissima is an isohydric one ( Wang and Zhou, 2000 ; Li et al, 2020 ).…”

GF14f gene is negatively associated with yield and grain chalkiness under rice ratooning

“…It has been widely accepted that the role of plant hormones, especially regarding abscisic acid (ABA), determines the intimate relationship between senescence and carbon reserve remobilization ( Yang et al., 2002 ; Yang et al., 2006 ; Wu et al., 2008 ). For example, ABA promotes the transference of carbohydrates from stem to grain by regulating the relative gene expression in carbon reserve remobilization ( Wang and Zhang, 2020 ; Wang et al., 2020 ). Meanwhile, the sucrose and abscisic acid interaction affected the activities of key enzymes in sucrose-to-starch conversion ( Tang et al., 2009 ; Wang et al., 2015 ), thereby regulating the grain-filling process.…”

Quantifying Key Points of Hydraulic Vulnerability Curves From Drought-Rewatering Experiment Using Differential Method

“…Robinia pseudoacacia L. is the dominant species in the warm temperate zone (Wang et al, 2020 ), and it is an anisohydric species, which is sensitive to drought. In addition, it will have a separatrix on the stem when severe drought occurs (Li et al, 2019 , 2020 ), which could provide a suitable opportunity to study the key hydraulic points using experimental methods.…”