Dataset Information

Growth responses of the mangrove Avicennia marina to salinity: development and function of shoot hydraulic systems require saline conditions.

ABSTRACT:

Background and aims

Halophytic eudicots are characterized by enhanced growth under saline conditions. This study combines physiological and anatomical analyses to identify processes underlying growth responses of the mangrove Avicennia marina to salinities ranging from fresh- to seawater conditions.

Methods

Following pre-exhaustion of cotyledonary reserves under optimal conditions (i.e. 50% seawater), seedlings of A. marina were grown hydroponically in dilutions of seawater amended with nutrients. Whole-plant growth characteristics were analysed in relation to dry mass accumulation and its allocation to different plant parts. Gas exchange characteristics and stable carbon isotopic composition of leaves were measured to evaluate water use in relation to carbon gain. Stem and leaf hydraulic anatomy were measured in relation to plant water use and growth.

Key results

Avicennia marina seedlings failed to grow in 0-5% seawater, whereas maximal growth occurred in 50-75% seawater. Relative growth rates were affected by changes in leaf area ratio (LAR) and net assimilation rate (NAR) along the salinity gradient, with NAR generally being more important. Gas exchange characteristics followed the same trends as plant growth, with assimilation rates and stomatal conductance being greatest in leaves grown in 50-75% seawater. However, water use efficiency was maintained nearly constant across all salinities, consistent with carbon isotopic signatures. Anatomical studies revealed variation in rates of development and composition of hydraulic tissues that were consistent with salinity-dependent patterns in water use and growth, including a structural explanation for low stomatal conductance and growth under low salinity.

Conclusions

The results identified stem and leaf transport systems as central to understanding the integrated growth responses to variation in salinity from fresh- to seawater conditions. Avicennia marina was revealed as an obligate halophyte, requiring saline conditions for development of the transport systems needed to sustain water use and carbon gain.

SUBMITTER: Nguyen HT

PROVIDER: S-EPMC4332612 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature

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Publications

Growth responses of the mangrove Avicennia marina to salinity: development and function of shoot hydraulic systems require saline conditions.

Nguyen Hoa T HT Stanton Daniel E DE Schmitz Nele N Farquhar Graham D GD Ball Marilyn C MC

Annals of botany 20150119 3

<h4>Background and aims</h4>Halophytic eudicots are characterized by enhanced growth under saline conditions. This study combines physiological and anatomical analyses to identify processes underlying growth responses of the mangrove Avicennia marina to salinities ranging from fresh- to seawater conditions.<h4>Methods</h4>Following pre-exhaustion of cotyledonary reserves under optimal conditions (i.e. 50% seawater), seedlings of A. marina were grown hydroponically in dilutions of seawater amende ...[more]

PMID: 25600273

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Project description:It is of great significance to explore the structure and salinity response of microbial communities in salt-tolerant plants to understand the mechanisms of plant-microbe interactions. Herein, we investigated the phyllosphere and rhizosphere microbial communities of Avicennia marina, a pioneer salt-tolerant plant, at three sites with different salinities in the coastal intertidal zone. The results showed that salinity had different effects on phyllosphere and rhizosphere microbial communities and had a greater impact on bacterial communities and bacterial network interactions. The rhizosphere bacterial community alpha diversity significantly increased with increasing salinity. Moreover, the relative abundance of Proteobacteria decreased significantly, while that of Bacteroidota and Actinobacteriota, with stronger salt tolerance and nutrient utilization capacity, increased significantly. Functional prediction indicated that the microbial communities could produce catalase, peroxidase, 3-phytase, and tryptophan synthase, which may exert potential antistress and growth-promoting functions. Among them, catalase, 3-phytase, alkaline phosphatase, and acid phosphatase increased significantly in the phyllosphere and rhizosphere bacterial communities and the phyllosphere fungal community with increasing salinity. Importantly, the dominant taxa Kushneria and Bacillus, which are salt tolerant and growth promoting, were isolated from the phyllosphere and rhizosphere, respectively, and verified to have the ability to alleviate salt stress and promote the growth of rice. IMPORTANCE Avicennia marina is a pioneer salt-tolerant plant in coastal intertidal mangroves, an efficient blue carbon ecosystem. It is of great importance to explore how salinity affects the phyllosphere and rhizosphere microbial communities of A. marina. This study showed that the microbial communities in the phyllosphere and rhizosphere of A. marina had different constitutive properties, adaptive network interactions, and potential stress-promoting functions. Furthermore, the dominant bacteria Kushneria and Bacillus were obtained from the phyllosphere and rhizosphere, respectively, and their coculture with rice could effectively alleviate salt stress and promote rice growth. Additionally, the effects of salinity changes on microbial community structure, associations, and functional potential in the phyllosphere and rhizosphere of A. marina were observed. This study has enriched our understanding of the microbial community structure, function, and ecological stability of mangrove species in coastal intertidal zones and has practical significance for improving crop yield by using salt-tolerant plant microbiomes.

Dataset Information

Growth responses of the mangrove Avicennia marina to salinity: development and function of shoot hydraulic systems require saline conditions.

Background and aims

Methods

Key results

Conclusions

Publications

Growth responses of the mangrove Avicennia marina to salinity: development and function of shoot hydraulic systems require saline conditions.

Similar Datasets

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