Contrasting Water Use, Stomatal Regulation, Embolism Resistance, and Drought Responses of Two Co-Occurring Mangroves

The physiological mechanisms underlying drought responses are poorly documented in mangroves, which experience nearly constant exposure to saline water. We measured gas exchange, foliar abscisic acid (ABA) concentration, and vulnerability to embolism in a soil water-withholding experiment of two co-occurring mangroves, Avicennia marina (Forsskål) Vierhapper (Verbenaceae) and Bruguiera gymnorrhiza (L.) Savigny (Rhizophoraceae). A. marina showed higher photosynthesis and transpiration than B. gymnorrhiza under well-watered conditions. Cavitation resistance differed significantly between species, with 50% cavitation occurring at a water potential (P50) of −8.30 MPa for A. marina and −2.83 MPa for B. gymnorrhiza. This large difference in cavitation resistance was associated with differences in stomatal closure and leaf wilting. The rapid stomatal closure of B. gymnorrhiza was correlated with ABA accumulation as water potential declined. Meanwhile, stomatal closure and declining water potentials in A. marina were not associated with ABA accumulation. The safety margins, calculated as the difference between stomatal closure and embolism spread, differed between these two species (1.59 MPa for A. marina vs. 0.52 MPa for B. gymnorrhiza). Therefore, A. marina adopts a drought tolerance strategy with high cavitation resistance, while B. gymnorrhiza uses a drought avoidance-like strategy with ABA-related sensitive stomatal control to protect its vulnerable xylem.

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DROUGHT RESISTANCE OF SORGHUM BICOLOR. 1. DROUGHT AVOIDANCE MECHANISMS RELATED TO LEAF WATER STATUS

Canadian Journal of Plant Science ◽

10.4141/cjps78-031 ◽

1978 ◽

Vol 58 (1) ◽

pp. 213-224 ◽

Cited By ~ 27

Author(s):

DARRYL G. STOUT ◽

GRAHAM M. SIMPSON

Keyword(s):

Sorghum Bicolor ◽

Water Status ◽

Stomatal Closure ◽

Irrigation Treatment ◽

Ageing Effect ◽

Leaf Water Status ◽

Drought Avoidance ◽

Diffusive Resistance ◽

The Difference ◽

Sorghum Bicolor L

Leaf ψs (osmotic potential) of two Sorghum bicolor (L.) Moench cultivars M35 and NK300 given an irrigation treatment decreased with increasing plant age. Following 3 wk without irrigation, leaf ψs of plants of both cultivars was lower than that in irrigated controls. Following 9 wk without irrigation, leaf ψs of M35 plants was still significantly lower than that in irrigated controls; but in NK300 the difference in leaf ψs between irrigated and non-irrigated plants was no longer significant due to an ageing effect changing leaf ψs less in non-irrigated than in irrigated plants. Evidence indicated that leaf ψs decreased due to osmoregulation, a drought avoidance mechanism, resulting in formation of more osmotically active cellular solutes. Greater leaf senescence of non-irrigated plants is a second drought avoidance mechanism used by sorghum to decrease transpiration requirements. Leaf diffusive resistance measurements indicated open stomata in both irrigated and non-irrigated plants so that under the imposed water stress conditions stomatal closure was not affecting the transpiration requirement.

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Photosynthetic responses to submergence in mangrove seedlings

Marine and Freshwater Research ◽

10.1071/mf13167 ◽

2014 ◽

Vol 65 (6) ◽

pp. 497 ◽

Cited By ~ 10

Author(s):

Mwita M. Mangora ◽

Matern S. P. Mtolera ◽

Mats Björk

Keyword(s):

Electron Transport Rate ◽

Saline Water ◽

Survival Rates ◽

Avicennia Marina ◽

Significant Decline ◽

Bruguiera Gymnorrhiza ◽

Photosynthetic Rates ◽

Run Off ◽

Mangrove Seedlings ◽

Photosynthetic Responses

Flooding and salinity fluctuations are common in mangrove systems. Sometimes these events are long-lasting, persisting several months. With an increased frequency of heavy rainfalls and terrestrial run-off, subsequent floods have been associated with massive mangrove mortality and failure to regenerate in the region. Owing to climate change, these events are expected to be more common in the future. We investigated how three weeks of submergence in water of different salinities affected the photosynthetic rates in seedlings of three common mangroves: Bruguiera gymnorrhiza (L.) Lamk.; Avicennia marina (Forssk.) Vierh.; and Heritiera littoralis Dryand. We found that photosynthesis and survival rates declined with increasing salinity and submergence time for all species. Prolonged submergence caused a significant decline in photosynthetic rates (as electron transport rate – ETR) for B. gymnorrhiza (P = 0.021) and H. littoralis (P = 0.002), whereas significant effects of both salinity (P = 0.003) and submergence (P = 0.023) were observed between species. Maximum diurnal values of ETR declined in the order of A. marina > B. gymnorrhiza > H. littoralis. After submergence, survived seedlings were tended normally, watered twice a day with freshwater. Three seedlings of B. gymnorrhiza from freshwater and 33% seawater treatments and of A. marina from freshwater treatment displayed signs of recovery for the first 3–5 days, but after that they died. We conclude that submergence time and water salinity will affect the performance of mangrove areas, such that areas experiencing prolonged submergence with flooding dominated by saline water might be most severely impacted.

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Drought resistance of cotton (Gossypium hirsutum) is promoted by early stomatal closure and leaf shedding

Functional Plant Biology ◽

10.1071/fp19093 ◽

2020 ◽

Vol 47 (2) ◽

pp. 91 ◽

Cited By ~ 4

Author(s):

Ximeng Li ◽

Renee Smith ◽

Brendan Choat ◽

David T. Tissue

Keyword(s):

Gossypium Hirsutum ◽

Water Potential ◽

Drought Resistance ◽

Leaf Gas Exchange ◽

Stomatal Closure ◽

Water Shortage ◽

Drought Avoidance ◽

Xylem Vulnerability ◽

Leaf Shedding

Water relations have been well documented in tree species, but relatively little is known about the hydraulic characteristics of crops. Here, we report on the hydraulic strategy of cotton (Gossypium hirsutum L.). Leaf gas exchange and in vivo embolism formation were monitored simultaneously on plants that were dried down in situ under controlled environment conditions, and xylem vulnerability to embolism of leaves, stems and roots was measured using intact plants. Water potential inducing 50% embolised vessels (P50) in leaves was significantly higher (less negative) than P50 of stems and roots, suggesting that leaves were the most vulnerable organ to embolism. Furthermore, the water potential generating stomatal closure (Pgs) was higher than required to generate embolism formation, and complete stomatal closure always preceded the onset of embolism with declining soil water content. Although protracted drought resulted in massive leaf shedding, stem embolism remained minimal even after ~90% leaf area was lost. Overall, cotton maintained hydraulic integrity during long-term drought stress through early stomatal closure and leaf shedding, thus exhibiting a drought avoidance strategy. Given that water potentials triggering xylem embolism are uncommon under field conditions, cotton is unlikely to experience hydraulic dysfunction except under extreme climates. Results of this study provide physiological evidence for drought resistance in cotton with regard to hydraulics, and may provide guidance in developing irrigation schedules during periods of water shortage.

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KAJIAN NILAI EKONOMIS DAN DAMPAK SOSIAL KEBERADAAN EKOSISTEM MANGROVE TERHADAP MASYARAKAT PESISIR

Jurnal Ekonomi dan Pembangunan ◽

10.22373/jep.v11i1.58 ◽

2020 ◽

Vol 11 (1) ◽

pp. 1-10

Author(s):

Agus Putra A. Samad ◽

Pitri Agustina ◽

Mus Herri

Keyword(s):

Avicennia Marina ◽

Rhizophora Mucronata ◽

Bruguiera Gymnorrhiza ◽

Sonneratia Caseolaris ◽

Rhizophora Apiculata ◽

Xylocarpus Granatum ◽

Bruguiera Parviflora

Langsa merupakan salah satu kota pesisir Aceh yang memiliki kawasan mangrove yang sangat potensial. Kota ini memiliki panjang garis pantai 16 km dengan luas kawasan mangrove sebesar 7.837 Ha. Keberadaan mangrove di wilayah ini menjadi aset strategis untuk dikembangkan menjadi basis kegiatan ekonomi untuk memakmurkan masyarakat dan meningkatkan pendapatan asli daerah. Tujuan utama penelitian ini adalah untuk melestarikan potensi sumberdaya ekosistem mangrove yang ada di Kota Langsa agar dapat memberikan fungsi ekologis dan ekonomis secara berkesinambungan kepada masyarakat disekitarnya. Kajian ini dilakukan menggunakan metode survei, analisa laboratorium dan observasi lapangan. Hasil pengamatan terhadap komposisi jenis tumbuhan yang terdapat di ekosistem mangrove menunjukkan 8 jenis tumbuhan mangrove yaitu: jenis Avicennia lanata, Avicennia marina, Bruguiera gymnorrhiza, Bruguiera parviflora, Rhizophora apiculata, Rhizophora mucronata, Sonneratia Caseolaris dan Xylocarpus granatum. Nilai rata-rata parameter kualitas air di ekosistem mangrove secara beturut-turut adalah DO (6.3 ppm),salinitas (27 ‰), pH tanah dasar (6.0), pH tanah permukaan (5.08), pH air (7.33), suhu (30 oC) dan kecerahan (5 m). Perhitungan terhadap nilai manfaat ekosistem mangrove meliputi: 1) Nilai manfaat langsung perikanan tangkap: Rp. 8.710.000.000 per tahun, 2) Nilai manfaat budidaya tambak: Rp. 93.940.000.000,- per tahun, 3) Nilai penahan abrasi dan banjir: Rp. 300.000.000,- per hektar per tahun, 4) Nilai sebagai penyediaan unsur hara: Rp. 28.634.000,- per tahun, 5) Nilai manfaat pilihan: Rp. 210.000.000,- per tahun dan 6) Nilai manfaat keberadaan: Rp. 1.464.493.000,- per tahun. Nilai keberadaan ekosistem mangrove yang dinilai adalah Nilai Keaslian = 70 % (lebih dari asli), Nilai Keindahan Alam = 74 % (lebih dari indah), Nilai Kenyamanan = 66% (kondisi lebih dari nyaman), dan Nilai Aspirasi masyarakat = 98 % (sangat didukung masyarakat). Alternatif pengelolaan dan pemanfaatan ekosistem mangrove yang diperkirakan cocok secara ekonomi dan ekologis terdiri dari beberapa kegiatan pilihan yaitu budidaya ikan, udang, tiram dan kepiting, budidaya ikan kerapu dan kakap, pengolahan buah dan daun mangrove, dan pengembangan obyek wisata.

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Interactions between leaf water potential, stomatal conductance and abscisic acid content of orange trees submitted to drought stress

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202004000300005 ◽

2004 ◽

Vol 16 (3) ◽

pp. 155-161 ◽

Cited By ~ 38

Author(s):

Mara de Menezes de Assis Gomes ◽

Ana Maria Magalhães Andrade Lagôa ◽

Camilo Lázaro Medina ◽

Eduardo Caruso Machado ◽

Marcos Antônio Machado

Keyword(s):

Abscisic Acid ◽

Water Stress ◽

Stomatal Conductance ◽

Water Potential ◽

Leaf Water Potential ◽

Acid Content ◽

Stomatal Closure ◽

Leaf Water ◽

Orange Trees ◽

Abscisic Acid Content

Thirty-month-old 'Pêra' orange trees grafted on 'Rangpur' lemon trees grown in 100 L pots were submitted to water stress by the suspension of irrigation. CO2 assimilation (A), transpiration (E) and stomatal conductance (g s) values declined from the seventh day of stress, although the leaf water potential at 6:00 a.m. (psipd) and at 2:00 p.m. (psi2) began to decline from the fifth day of water deficiency. The CO2 intercellular concentration (Ci) of water-stressed plants increased from the seventh day, reaching a maximum concentration on the day of most severe stress. The carboxylation efficiency, as revealed by the ratio A/Ci was low on this day and did not show the same values of non-stressed plants even after ten days of rewatering. After five days of rewatering only psi pd and psi2 were similar to control plants while A, E and g s were still different. When psi2 decreases, there was a trend for increasing abscisic acid (ABA) concentration in the leaves. Similarly, stomatal conductance was found to decrease as a function of decreasing psi2. ABA accumulation and stomatal closure occurred when psi2 was lower than -1.0 MPa. Water stress in 'Pera´ orange trees increased abscisic acid content with consequent stomatal closure and decreased psi2 values.

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KEANEKARAGAMAN JENIS MANGROVE DI DESA MENDALOK KECAMATAN SUNGAI KUNYIT KABUPATEN MEMPAWAH

JURNAL HUTAN LESTARI ◽

10.26418/jhl.v7i1.31251 ◽

2019 ◽

Vol 7 (1) ◽

Author(s):

Syahrul Muharamsyah ◽

M Sofwan Anwari ◽

Hafiz Ardian

Keyword(s):

Mangrove Forest ◽

Avicennia Marina ◽

Raw Material ◽

Mangrove Forests ◽

Bruguiera Gymnorrhiza ◽

Mangrove Species ◽

Rhizophora Stylosa ◽

Sonneratia Caseolaris ◽

Rhizophora Apiculata ◽

Bruguiera Cylindrica

Mangrove forests are unique ecosystems that have ecological, biological and socio-economic functions. The function of mangrove forests on the environment is very important especially in the coastal and oceanic regions. Mangrove forests providers of wood, leaves as raw material for medicines, and natural dye. This study aims to inventory the diversity of species of mangrove vegetation in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. The benefits of this study are to provide the data on mangrove forest vegetation as basic data for local government and related agencies in efforts to protect and preserve mangrove forests in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency. Inventory the tree in mangrove forest used a line with measured 200 meters. There are 6 lines and the distance between the lines as far as 100 meters. The lines of observation are placed by purposive sampling. The results of research found 11 types of species and consisted of 6 genera. The genera are Avicennia, Bruguiera, Ceriops, Rhizophora, Soneratia and Xylocarpus. The species found were Avicennia alba, Avicennia marina, Bruguiera cylindrica, Bruguiera gymnorrhiza, Bruguiera parviflora, Ceriops decandra, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Sonneratia caseolaris, Xylocarpus mollucensis. Diversity of mangrove species in Mendalok Village, Sungai Kunyit Subdistrict, Mempawah Regency was high and should be maintained for conservation and ecotourism area. Keywords : conservation, ecotourism, mangrove, Mendalok Village

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EFFECT OF SALINE WATER AND POTASH FERTILIZER ON PROLINE CONTENT AND WATER POTENTAL IN PISUM SATIVUM L. (VAR.SENADOR CAMBADOS)

Baghdad Science Journal ◽

10.21123/bsj.4.3.351-357 ◽

2007 ◽

Vol 4 (3) ◽

pp. 351-357

Author(s):

Baghdad Science Journal

Keyword(s):

Pisum Sativum ◽

Water Potential ◽

Irrigation Water ◽

Saline Water ◽

Inhibitory Effect ◽

Proline Accumulation ◽

Proline Content ◽

Pisum Sativum L ◽

Main Plot ◽

Fertilizer Rates

Filed experiment was conducted to test the effect of saline water and potassium fertilizers rate on proline and water potential of Pisum sativum L. (Var.Senador Cambados ) leaves . Treatments of the experiment included two levels of water salinity( 2, 7 dSm-1) as a main plot and fertilizer rates as a sub plot. Results indicated that irrigation of plant with saline water 7 dSm-1 and fertilization 150 kg/donum increased proline accumulation and water potential 0.31 mmol/g,-17.00 bar at 9 AM morning and 0.62 mmol/g , -21.00 bar at 3 PM afternoon ,Irrigating plant with a 2 dSm-1 and fertilization 300 kg/donum decreased proline accumulation and water potential of leaves 0.22 mmol/g, -16.00 bar at 9 AM and 0.43 mmol/g,-18.00 bar at 3 PM . Irrigation plants with saline water 7 dSm-1 and fertilizer with 150 kg/ Donum K2SO4 increased Root/Shoot to 0.89 ,while 0.41 after irrigation with 2 dSm-1 saline water and fertilization with 300 kg/ Donum K2SO4 . The Na/K ratio increased to 0.53 under 7 dSm-1 of irrigation water and 150 kg/Donum fertilization and decreased to 0.1 under 2 dSm-1 irrigation water and fertilized 300 kg/ Donum . The results lead to the conclusion that potassium fertilization may reduce the inhibitory effect of increasing salinity of irrigation water on pea.

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Effects of Pinus taeda leaf anatomy on vascular and extravascular leaf hydraulic conductance as influenced by N-fertilization and elevated CO2

Journal of Plant Hydraulics ◽

10.20870/jph.2016.e007 ◽

2016 ◽

Vol 3 ◽

pp. e007 ◽

Cited By ~ 11

Author(s):

Jean-Christophe Domec ◽

Sari Palmroth ◽

Ram Oren

Keyword(s):

Water Potential ◽

Pinus Taeda ◽

Leaf Anatomy ◽

Environmental Changes ◽

Water Movement ◽

Stomatal Closure ◽

Hydraulic Conductance ◽

N Availability ◽

Leaf Hydraulic Conductance ◽

Bordered Pits

Silvicultural practices (e.g., nitrogen addition through fertilization) and environmental changes (e.g., elevated [CO2]) may alter needle structure, impacting mass and energy exchange between the biosphere and atmosphere through alteration of stomatal function. Hydraulic resistances in leaves, controlling the mass and energy exchanges, occur both in the xylem and in the flow paths across the mesophyll to evaporation sites, and therefore largely depends on the structure of the leaf. We used the Free-Air Carbon dioxide Enrichment (FACE) experiment, providing a unique setting for assessing the interaction effects of [CO2] and nitrogen (N) supply to examine how leaf morphological and anatomical characteristics control leaf hydraulic conductance (Kleaf) of loblolly pine (Pinus taeda L.) trees subjected to ambient or elevated (+200 ppmv) CO2 concentrations (CO2a and CO2e, respectively) and to soil nitrogen amendment (N). Our study revealed that CO2e decreased the number of tracheids per needle, and increased the distance from the xylem vascular bundle to the stomata cavities, perturbing the leaf hydraulic system. Both treatments induced a decrease in Kleaf, and CO2e also decreased leaf extravascular conductance (Kextravascular), the conductance to water flow from the xylem to the leaf-internal air space. Decline in Kleaf under CO2e was driven by the decline in Kextravascular, potentially due to longer path for water movement through the mesophyll, explaining the decline in stomatal conductance (gs) observed under CO2e. This suggests that the distance from vascular conduits to stomata sub-cavity was a major constraint of leaf water transport. Across treatments our results showed that needle vein conductivity was slightly more limited by the lumen than by the bordered-pits, the latter accounting for 30-45% of vein resistance. CO2e-induced reduction in Kleaf was also consistent with an increased resistance to xylem collapse due to thicker cell wall. In addition, stomatal closure corresponded to the water potential inducing a reduction in 50% of leaf vascular conductance (Kvascular) via xylem wall rupture. The water potential that was estimated to induce complete xylem wall collapse was related to the water potential at turgor loss. Our study provided a framework for understanding the interaction between CO2e and N availability in affecting leaf anatomy, and the mechanisms for the response of Kleaf to the treatments. These mechanisms can be incorporated into predictive models of gs, critical for estimating forest productivity in water limited environments in current and future climates and a landscape composed of sites of a range in soil N fertility.

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Water relations of winter wheat. 5. The root system and osmotic adjustment in relation to crop evaporation

The Journal of Agricultural Science ◽

10.1017/s0021859600042751 ◽

1984 ◽

Vol 102 (2) ◽

pp. 415-425 ◽

Cited By ~ 24

Author(s):

M. McGowan ◽

P. Blanch ◽

P. J. Gregory ◽

D. Haycock

Keyword(s):

Winter Wheat ◽

Water Potential ◽

Root System ◽

Soil Water ◽

Osmotic Adjustment ◽

Stomatal Closure ◽

Soil Water Potential ◽

Plant Water ◽

Potential Evaporation ◽

Plant Water Potential

SummaryShoot and root growth and associated leaf and soil water potential relations were compared in three consecutive crops of winter wheat grown in the same field. Despite a profuse root system the crop grown in the second drought year (1976) failed to dry the soil as throughly as the crops in 1975 and 1977. Measurements of plant water potential showed that the restricted utilization of soil water reserves by this crop was associated with failure to make any significant osmotic adjustment, leading to premature loss of leaf turgor and stomatal closure. The implications of these results for models to estimate actual crop evaporation from values of potential evaporation are discussed.

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A model of stomatal closure driven by nonlinearities in soil-plant hydraulics

10.5194/egusphere-egu21-12524 ◽

2021 ◽

Author(s):

Fabian Wankmüller ◽

Mohsen Zarebanadkouki ◽

Andrea Carminati

Keyword(s):

Hydraulic Conductivity ◽

Stomatal Conductance ◽

Water Potential ◽

Leaf Water Potential ◽

Environmental Conditions ◽

Plant Traits ◽

Stomatal Closure ◽

Leaf Water ◽

Optimization Models ◽

Soil Conditions

Predicting plant responses to drought is a long-standing research goal. Since stomata regulate gas-exchange between plants and the atmosphere, understanding their response to drought is fundamental. Current predictions of stomatal behavior during drought mainly rely on empirical models. These models may suit well to a specific set of plant traits and environmental growth conditions, but their predictive value is doubtful when atmospheric and soil conditions change. Stomatal optimization offers an alternative framework to predict stomatal regulation in response to drought for varying environmental conditions and plant traits. Models which apply this optimization principle posit that stomata maximize the carbon gain in relation to a penalty caused by water loss, such as xylem cavitation. Optimization models have the advantage of requiring a limited number of parameters and have been successfully used to predict stomatal response to drought for varying environmental conditions and species. However, a mechanism that enables stomata to optimally close in response to water limitations, and more precisely to a drop in the ability of the soil-plant continuum to sustain the transpiration demand, is not known. Here, we propose a model of stomatal regulation that is linked to abscisic acid (ABA) dynamics (production, degradation and transport) and that allows plants to avoid excessive drops in leaf water potential during soil drying and increasing vapor pressure deficit (VPD). The model assumes that: 1) stomatal conductance (gs) decreases when ABA concentration close to the guard cells (CABA) increases; 2) CABA increases with decreasing leaf water potential (due to higher production); and 3) CABA decreases with increasing photosynthesis (e.g. due to faster degradation or transport to the phloem). Our model includes simulations of leaf water potential based on transpiration rate, soil water potential and variable hydraulic conductances of key elements (rhizosphere, root and xylem), and a function linking stomatal conductance to assimilation. It was tested for different soil properties and VPD. The model predicts that stomata close when the relation between assimilation and leaf water potential becomes nonlinear. In wet soil conditions and low VPD, when there is no water limitation, this nonlinearity is controlled by the relation between stomatal conductance and assimilation. In dry soil conditions, when the soil hydraulic conductivity limits the water supply, nonlinearity is controlled by the excessive drop of leaf water potential for increasing transpiration rates. The model predicts different relations between stomatal conductance and leaf water potential for varying soil properties and VPD. For instance, the closure of stomata is more abrupt in sandy soil, reflecting the steep decrease in hydraulic conductivity of sandy soils. In summary, our model results in an optimal behavior, in which stomatal closure avoids excessive (nonlinear) decrease in leaf water potential, similar to other stomatal optimization models. As based on ABA concentration which increases with decreasing leaf water potential but declines with assimilation, this model is a preliminary attempt to link optimization models to a physiological mechanism.

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