Experimental evidence for weakened tree nutrient use and resorption efficiencies under severe drought in a subtropical monsoon forest

Abstract Aims The functions of global forests are threatened by the increasing frequency of severe drought. Due to drought inducing reductions in soil nutrient availability, efficiencies of nutrient use and resorption of trees become crucial for forest functions and biogeochemical cycles. However, understanding the dynamics of responses of foliar nutrient use and resorption efficiencies to drought, especially in tropical or subtropical forests, is still limited. Our goal was to detect whether and how the importance of leaf nutrient use and resorption changes across different species in the hot and wet forests when suffering drought stress in different months. Methods Based on a 70% throughfall exclusion experiment in a subtropical forest, we collected green and senesced leaves of Schima superba and Lithocarpus glaber in different months from October 2016 to May 2019, to estimate the effects of drought on leaf nitrogen (N) and phosphorus (P) use and resorption efficiencies (i.e. NUE and PUE, NRE and PRE). Important Findings The effects of drought on nutrient use and resorption efficiencies varied between species and months. Based on a 2-year observation, drought had no effect on S. superba, but significantly decreased NUE, NRE and PRE of L. glaber by 3.4%, 20.2% and 7.1%, respectively. Furthermore, the negative drought effects were aggravated by the natural summer drying in 2017. As a result, NUE and PUE of L. glaber were significantly depressed by 17.2% and 58.1%, while NRE and PRE were significantly reduced by 56.5% and 53.8% in August 2017. Moreover, the responses of NRE, PRE and NUE to drought were related with soil moisture (SM) for L. glaber, and when SM decreased to a threshold near 9 v/v%, drought effects were shifted from unresponsive to negative. Our results highlight a species-specific threshold response of nutrient use under drought in a subtropical forest.

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Nutrient use strategy and not competition determines native and invasive species response to changes in soil nutrient availability

Restoration Ecology ◽

10.1111/rec.13374 ◽

2021 ◽

Author(s):

Amanda E. Knauf ◽

Creighton M. Litton ◽

Rebecca J. Cole ◽

Jed P. Sparks ◽

Christian P. Giardina ◽

...

Keyword(s):

Invasive Species ◽

Nutrient Availability ◽

Soil Nutrient ◽

Soil Nutrient Availability ◽

Species Response ◽

Nutrient Use

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Spermine: Its Emerging Role in Regulating Drought Stress Responses in Plants

Cells ◽

10.3390/cells10020261 ◽

2021 ◽

Vol 10 (2) ◽

pp. 261

Author(s):

Md. Mahadi Hasan ◽

Milan Skalicky ◽

Mohammad Shah Jahan ◽

Md. Nazmul Hossain ◽

Zunaira Anwar ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Stress Responses ◽

Abiotic Stresses ◽

Defense Mechanisms ◽

Antioxidant Defense ◽

Severe Drought ◽

New Information ◽

Effects Of Drought

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.

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Enhancement of drought tolerance in diverse Vicia faba cultivars by inoculation with plant growth-promoting rhizobacteria under newly reclaimed soil conditions

Scientific Reports ◽

10.1038/s41598-021-02847-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Elsayed Mansour ◽

Hany A. M. Mahgoub ◽

Samir A. Mahgoub ◽

El-Sayed E. A. El-Sobky ◽

Mohamed I. Abdul-Hamid ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Plant Growth Promoting Rhizobacteria ◽

Severe Drought ◽

Drought Conditions ◽

Moderate Drought ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Effects Of Drought

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

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Effects of drought and meteorological forcing on carbon and water fluxes in Nordic forests during the dry summer of 2018

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2019.0516 ◽

2020 ◽

Vol 375 (1810) ◽

pp. 20190516

Author(s):

Anders Lindroth ◽

Jutta Holst ◽

Maj-Lena Linderson ◽

Mika Aurela ◽

Tobias Biermann ◽

...

Keyword(s):

Surface Conductance ◽

Severe Drought ◽

Water Fluxes ◽

Multilinear Regression ◽

Evaporative Demand ◽

Meteorological Forcing ◽

Continental Scale ◽

The Difference ◽

Effects Of Drought ◽

The Impact

The Nordic region was subjected to severe drought in 2018 with a particularly long-lasting and large soil water deficit in Denmark, Southern Sweden and Estonia. Here, we analyse the impact of the drought on carbon and water fluxes in 11 forest ecosystems of different composition: spruce, pine, mixed and deciduous. We assess the impact of drought on fluxes by estimating the difference (anomaly) between year 2018 and a reference year without drought. Unexpectedly, the evaporation was only slightly reduced during 2018 compared to the reference year at two sites while it increased or was nearly unchanged at all other sites. This occurred under a 40 to 60% reduction in mean surface conductance and the concurrent increase in evaporative demand due to the warm and dry weather. The anomaly in the net ecosystem productivity (NEP) was 93% explained by a multilinear regression with the anomaly in heterotrophic respiration and the relative precipitation deficit as independent variables. Most of the variation (77%) was explained by the heterotrophic component. Six out of 11 forests reduced their annual NEP with more than 50 g C m −2 yr −1 during 2018 as compared to the reference year. The NEP anomaly ranged between −389 and +74 g C m −2 yr −1 with a median value of −59 g C m −2 yr −1 . This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.

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Effects of Drought and Rehydration on the Physiological Responses of Artemisia halodendron

Water ◽

10.3390/w11040793 ◽

2019 ◽

Vol 11 (4) ◽

pp. 793

Author(s):

Juanli Chen ◽

Xueyong Zhao ◽

Yaqiu Zhang ◽

Yuqiang Li ◽

Yongqing Luo ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Drought Stress ◽

Membrane Permeability ◽

Chlorophyll Content ◽

Physiological Responses ◽

Severe Drought ◽

Native Plant ◽

Chlorophyll Fluorescence Parameters ◽

Artemisia Halodendron ◽

Effects Of Drought

Artemisia halodendron is a widely distributed native plant in China’s Horqin sandy land, but few studies have examined its physiological responses to drought and rehydration. To provide more information, we investigated the effects of drought and rehydration on the chlorophyll fluorescence parameters and physiological responses of A. halodendron to reveal the mechanisms responsible for A. halodendron’s tolerance of drought stress and the resulting ability to tolerate drought. We found that A. halodendron had strong drought resistance. Its chlorophyll content first increased and then decreased with prolonged drought. Variable chlorophyll fluorescence (Fv) and quantum efficiency of photosystem II (Fv/Fm) decreased, and the membrane permeability and malondialdehyde increased. When plants were subjected to drought stress, superoxide dismutase (SOD) activity degraded under severe drought, but the activities of peroxidase (POD) and catalase (CAT) and the contents of soluble proteins, soluble sugars, and free proline increased. Severe drought caused wilting of A. halodendron leaves and the leaves failed to recover even after rehydration. After rehydration, the chlorophyll content, membrane permeability, SOD and CAT activities, and the contents of the three osmoregulatory substances under moderate drought began to recover. However, Fv, Fv/Fm, malondialdehyde, and POD activity did not recover under severe drought. These results illustrated that drought tolerance of A. halodendron resulted from increased enzyme (POD and CAT) activities and accumulation of osmoregulatory substances.

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How Soil Nutrient Availability Influences Plant Biomass and How Biomass Stimulation Alleviates Heavy Metal Toxicity in Soils: The Cases of Nutrient Use Efficient Genotypes and Phytoremediators, Respectively

Biomass Now - Cultivation and Utilization ◽

10.5772/53594 ◽

2013 ◽

Cited By ~ 6

Author(s):

Theocharis Chatzistathis ◽

Ioannis Therios

Keyword(s):

Heavy Metal ◽

Nutrient Availability ◽

Metal Toxicity ◽

Plant Biomass ◽

Soil Nutrient ◽

Heavy Metal Toxicity ◽

Soil Nutrient Availability ◽

Nutrient Use

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Effects of drought on photosynthesis in grapevines under field conditions: an evaluation of stomatal and mesophyll limitations

Functional Plant Biology ◽

10.1071/pp01119 ◽

2002 ◽

Vol 29 (4) ◽

pp. 461 ◽

Cited By ~ 370

Author(s):

Jaume Flexas ◽

Josefina Bota ◽

José M. Escalona ◽

Bartolomé Sampol ◽

Hipólito Medrano

Keyword(s):

Chlorophyll Fluorescence ◽

Electron Transport Rate ◽

Net Photosynthesis ◽

Co2 Concentration ◽

Vitis Vinifera L ◽

Severe Drought ◽

Mesophyll Conductance ◽

Progressive Decline ◽

Effects Of Drought ◽

Combined Measurements

The effect of diffusional and photochemical limitations to photosynthesis was assessed in field-grown water-stressed grapevines (Vitis vinifera L.) by combined measurements of gas exchange and chlorophyll fluorescence. Drought was slowly induced, and the progressive decline of photosynthesis was examined in different grapevine cultivars along a continuous gradient of maximum mid-morning values of stomatal conductance (g), which were used as an integrative indicator of the water-stress conditions endured by the leaves. Initial decreases of g were accompanied by decreases of substomatal CO2 concentration (Ci), the estimated chloroplastic CO2 concentration (Cc) and net photosynthesis (AN), while electron transport rate (ETR) remained unaffected. With increasing drought, g, AN, Ci and Cc further decreased, accompanied by slight decreases of ETR and of the estimated mesophyll conductance (gmes). Severe drought led to strong reductions of both g and gmes, as well as of ETR. The apparent carboxylation efficiency and the compensation point for CO2 remained unchanged under severe drought when analysed on a Cc, rather than a Ci, basis, suggesting that previously reported metabolic impairment was probably due to decreased gmes.

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Forest dynamics of a subtropical monsoon forest in Dinghushan, China: recruitment, mortality and the pace of community change

Journal of Tropical Ecology ◽

10.1017/s0266467413000059 ◽

2013 ◽

Vol 29 (2) ◽

pp. 131-145 ◽

Cited By ~ 23

Author(s):

Yong Shen ◽

Louis S. Santiago ◽

Lei Ma ◽

Guo-Jun Lin ◽

Ju-Yu Lian ◽

...

Keyword(s):

Tropical Forests ◽

Forest Dynamics ◽

Tree Mortality ◽

Population Change ◽

Interspecific Interactions ◽

Community Change ◽

Subtropical Forest ◽

Size Class ◽

Forest Plot ◽

Monsoon Forest

Abstract:Structure and demographics in many tropical forests is changing, but the causes of these changes remain unclear. We studied 5 y (2005–2010) of species turnover, recruitment, mortality and population change data from a 20-ha subtropical forest plot in Dinghushan, China, to identify trends in forest change, and to test whether tree mortality is associated with intraspecific or interspecific competition. We found the Dinghushan forest to be more dynamic than one temperate and two tropical forests in a comparison of large, long-term forest dynamics plots. Within Dinghushan, size-class distributions were bell-shaped only for the three most dominant species and reverse J-shaped for other species. Bell-shaped population distributions can indicate a population in decline, but our data suggest that these large and long-lived species are not in decline because the pattern is driven by increasing probabilities of transition to larger size class with increasing size and fast growth in saplings. Spatially aggregated tree species distributions were common for surviving and dead individuals. Competitive associations were more frequently intraspecific than interspecific. The competition that induced tree mortality was more associated with intraspecific than interspecific interactions. Intraspecific competitive exclusion and density-dependence appear to play important roles in tree mortality in this subtropical forest.

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Rainfall but not selective logging affect changes in abundance of a tropical forest butterfly in Sabah, Borneo

Journal of Tropical Ecology ◽

10.1017/s0266467403003055 ◽

2003 ◽

Vol 19 (1) ◽

pp. 35-42 ◽

Cited By ~ 23

Author(s):

J. K. Hill ◽

K. C. Hamer ◽

M. M. Dawood ◽

J. Tangah ◽

V. K. Chey

Keyword(s):

Forest Fires ◽

Southern Oscillation ◽

Selective Logging ◽

Severe Drought ◽

Direct Effects ◽

High Rainfall ◽

Enso Events ◽

Effects Of Drought ◽

Butterfly Population ◽

Abundance And Distribution

We investigated the effects of rainfall on the distribution and abundance of the satyrine butterfly Ragadia makuta in selectively logged and unlogged forest on Borneo. In 1997-98, there was a severe El Niño-Southern Oscillation (ENSO) drought, and annual surveys over a 4-y period showed that abundance of R. makuta was greatly reduced during the drought, but that populations quickly recovered after it. Monthly surveys over a 12-mo period of typical rainfall showed that high rainfall in the month preceding surveys significantly reduced butterfly abundance. Butterfly abundance and distribution did not differ between selectively logged and unlogged areas in either monthly or annual surveys and there was no difference between selectively logged and unlogged areas in the pattern of post-drought recovery. These results indicate that the abundance of R. makuta was significantly reduced both after high rainfall and during severe drought, but that these impacts were short-lived and were not affected by habitat disturbance. ENSO droughts on Borneo naturally often lead to widespread forest fires and thus impacts of ENSO events for butterflies are more likely to be due to indirect effects of habitat loss, rather than direct effects of drought on butterfly population dynamics.

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