Spectral assessments of wheat plants grown in pots and containers under saline conditions

2013 ◽  
Vol 40 (4) ◽  
pp. 409 ◽  
Author(s):  
Harald Hackl ◽  
Bodo Mistele ◽  
Yuncai Hu ◽  
Urs Schmidhalter
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Aboveground Biomass ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Spectral Indices ◽  
Fresh Weight ◽  
Normalised Difference Vegetation Index ◽  
Spectral Sensing ◽  
Reflectance Ratio

Spectral measurements allow fast nondestructive assessment of plant traits under controlled greenhouse and close-to-field conditions. Field crop stands differ from pot-grown plants, which may affect the ability to assess stress-related traits by nondestructive high-throughput measurements. This study analysed the potential to detect salt stress-related traits of spring wheat (Triticum aestivum L.) cultivars grown in pots or in a close-to-field container platform. In two experiments, selected spectral indices assessed by active and passive spectral sensing were related to the fresh weight of the aboveground biomass, the water content of the aboveground biomass, the leaf water potential and the relative leaf water content of two cultivars with different salt tolerance. The traits were better ascertained by spectral sensing of container-grown plants compared with pot-grown plants. This may be due to a decreased match between the sensors’ footprint and the plant area of the pot-grown plants, which was further characterised by enhanced senescence of lower leaves. The reflectance ratio R760 : R670, the normalised difference vegetation index and the reflectance ratio R780 : R550 spectral indices were the best indices and were significantly related to the fresh weight, the water content of the aboveground biomass and the water potential of the youngest fully developed leaf. Passive sensors delivered similar relationships to active sensors. Across all treatments, both cultivars were successfully differentiated using either destructively or nondestructively assessed parameters. Although spectral sensors provide fast and qualitatively good assessments of the traits of salt-stressed plants, further research is required to describe the potential and limitations of spectral sensing.

scholarly journals Estimating Vertical Distribution of Leaf Water Content within Wheat Canopies after Head Emergence

2021 ◽  
Vol 13 (20) ◽  
pp. 4125
Author(s):  
Weiping Kong ◽  
Wenjiang Huang ◽  
Lingling Ma ◽  
Lingli Tang ◽  
Chuanrong Li ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Water Content ◽  
Near Infrared ◽  
Field Experiments ◽  
Estimation Method ◽  
Middle Layer ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Growth Stages ◽  
Spectral Indices

Monitoring vertical profile of leaf water content (LWC) within wheat canopies after head emergence is vital significant for increasing crop yield. However, the estimation of vertical distribution of LWC from remote sensing data is still challenging due to the effects of wheat spikes and the efficacy of sensor measurement from the nadir direction. Using two-year field experiments with different growth stages after head emergence, N rates, wheat cultivars, we investigated the vertical distribution of LWC within canopies, the changes of canopy reflectance after spikes removal, the relationship between spectral indices and LWC in the upper-, middle- and bottom-layer. The interrelationship among vertical LWC were constructed, and four ratio of reflectance difference (RRD) type of indices were proposed based on the published WI and NDWSI indices to determine vertical distribution of LWC. The results indicated a bell shape distribution of LWC in wheat plants with the highest value appeared at the middle layer, and significant linear correlations between middle-LWC vs. upper-LWC and middle-LWC vs. bottom-LWC (r ≥ 0.92) were identified. The effects of wheat spikes on spectral reflectance mainly occurred in near infrared to shortwave infrared regions, which then decreased the accuracy of LWC estimation. Spectral indices at the middle layer outperformed the other two layers in LWC assessment and were less susceptible to wheat spikes effects, in particular, the newly proposed narrow-band WI-4 and NDWSI-4 indices exhibited great potential in tracking the changes of middle-LWC (R2 = 0.82 and 0.84, respectively). By taking into account the effects of wheat spikes and the interrelationship of vertical LWC within canopies, an indirect induction strategy was developed for modeling the upper-LWC and bottom-LWC. It was found that the indirect induction models based on the WI-4 and NDWSI-4 indices were more effective than the models obtained from conventional direct estimation method, with R2 of 0.78 and 0.81 for the upper-LWC estimation, and 0.75 and 0.74 for the bottom-LWC estimation, respectively.

Water Relations and Leaf Structure of the Evergreen Shrubs Eurya emarginata (Theaceae) and E. japonica in Coastal and Inland Habitats

1998 ◽  
Vol 46 (1) ◽  
pp. 135 ◽  
Author(s):  
Masako Mishio ◽  
Naoki Kachi
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Unit Area ◽  
Leaf Water ◽  
Photon Flux ◽  
Leaf Water Content ◽  
Shrub Species ◽  
Eurya Emarginata

Stomatal conductance and leaf water potential at around noon, pre-dawn leaf water potential, pressure–volume parameters, and leaf structural characteristics including leaf thickness, leaf dry mass per unit area and turgid leaf water content per unit area were compared between a coastal shrub species, Eurya emarginata (Thunb.) Makino and an inland shrub species, E. japonica Thunb. The pre-dawn leaf water potential was only slightly lower in E. emarginata than in E. japonica, and the environmental conditions such as the photosynthetic photon flux density and the vapour pressure deficit did not differ obviously between the two habitats. No apparent differences were observed in the pressure–volume parameters between the two species. On the other hand, E. emarginata had much higher stomatal conductance and significantly thicker leaves with higher turgid leaf water content per unit area than E. japonica. The thicker leaf with higher water content on an area basis in E. emarginata maintains adequate leaf turgor pressure against a higher rate of transpiration.

scholarly journals KANDUNGAN AIR PADA SEGMEN DAUN TANAMAN PADI (Oryza sativa L.) LOKAL SULAWESI UTARA SAAT KEKERINGAN YANG DIINDUKSI DENGAN POLIETILEN GLIKOL 8000

2018 ◽  
Vol 18 (2) ◽  
pp. 63
Author(s):  
Risa Junita Mereh ◽  
Nio Song Ai ◽  
Parluhutan Siahaan
Keyword(s):  
Oryza Sativa ◽  
Water Potential ◽  
Water Content ◽  
Oryza Sativa L ◽  
Leaf Water ◽  
Leaf Segment ◽  
Leaf Water Content ◽  
North Sulawesi ◽  
Leaf Segments ◽  
Peg 8000

KANDUNGAN AIR PADA SEGMEN DAUN TANAMAN PADI (Oryza sativa L.) LOKAL SULAWESI UTARA SAAT KEKERINGAN YANG DIINDUKSI DENGAN POLIETILEN GLIKOL 8000 ABSTRAKPenelitian ini telah dilakukan untuk mengkaji kandungan air sebagai respon fisiologi pada segmen daun tanaman padi lokal Sulut (varietas Temo, Ombong, Burungan, dan Superwin) terhadap kekeringan yang diinduksi dengan PEG 8000 secara in vitro. Segmen daun padi dipotong-potong 1 cm x 1 cm dan diberi tiga macam perlakuan PEG 8000 (dengan potensial air/PA medium 0; -0,25; dan -0,5 MPa), dan empat waktu pengambilan sampel (0, 4, 8 dan 12 jam) dalam tiga kali ulangan. Hasil penelitian menunjukkan bahwa bahwa faktor varietas, faktor waktu perlakuan,  faktor konsentrasi PEG 8000, dan interaksi antara ketiga faktor tersebut tidak menyebabkan perbedaan kandungan air segmen daun yang nyata.Kata kunci: Cekaman kekeringan, PEG 8000, Potensial air, Segmen daun LEAF WATER CONTENT IN LEAF SEGMENTS OF NORTH SULAWESI LOCAL RICE (Oryza sativa L.)  UNDER POLYETHYLENE-GLYCOL- 8000-INDUCED DROUGHTED DROUGHTABSTRACTA study was conducted to evaluate leaf water content as one of physiological responses in leaf segments of North Sulawesi local rice (cv. Temo, Ombong, Burungan, and Superwin) under PEG 8000- induced-drought. The rice leaves were cut into 1 cm x 1 cm segments and treated withPEG 8000 solutions  (medium water potential or PA of 0; -0.25; and -0.5 MPa),four sampling times (0, 4, 8 and 12 hours) and 3 replicates. The results indicated that factors of varieties, treatment period, concentration of PEG 8000, and interaction among these factors did not result in any differences in water content of rice leaf segments.Keywords: Drought stress, PEG 8000, Water potential, Leaf segment

scholarly journals Kandungan Air Daun Padi Lokal Sulawesi Utara terhadap Kekeringan yang Diinduksi dengan Polietilen Glikol 8000 (Leaf Water Content of North Sulawesi Local Rice under Polyethylene-Glycol-8000 -Induced Drought)

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Monalisa Pirade ◽  
Song Ai Nio ◽  
Parluhutan Siahaan
Keyword(s):  
Polyethylene Glycol ◽  
Water Potential ◽  
Water Content ◽  
Treatment Period ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Rice Varieties ◽  
North Sulawesi ◽  
Peg 8000 ◽  
Physiological Indicator

Abstrak Perubahan iklim menjadi salah satu penyebab terjadinya kekeringan dan kondisi ini dapat menurunkan produksi padi. Polietilen glikol (PEG) mampu menurunkan potensial air dalam larutan, sehingga dapat digunakan untuk menginduksi kekeringan. Penelitian ini bertujuan untuk mengkaji ada tidaknya perbedaan respons fisiologis berdasarkan kandungan air daun pada tanaman padi lokal Sulawesi Utara yang mengalami kekeringan dengan induksi PEG 8000. Hasil penelitian ini menunjukkan bahwa faktor varietas (Superwin, Burungan, Ombong, dan Temo), faktor konsentrasi PEG 8000 (potensial air medium 0, –0,25 dan –0,5 MPa), faktor waktu perlakuan (0, 6 dan 12 jam), interaksi antara faktor varietas dan konsentrasi PEG, interaksi antara faktor varietas dan waktu perlakuan, interaksi antara faktor konsentrasi dan waktu perlakuan, interaksi antara faktor varietas, konsentrasi PEG, dan waktu perlakuan dalam cekaman kekeringan tidak menyebabkan perbedaan kandungan air daun yang nyata. Dalam penelitian ini  kandungan air daun tidak dapat dijadikan sebagai indikator respons fisiologis pada keempat varietas padi lokal Sulawesi Utara terhadap cekaman kekeringan. Kata kunci: cekaman kekeringan, PEG, kandungan air daun, padi lokal Sulawesi Utara  AbstractClimate change can result in drought and this condition can reduce rice production. Polyethylene glycol (PEG) decreases the water potential in the nutrient solution, therefore, it can be used to induce drought. The purpose of this research was to evaluate physiological response of North Sulawesi local rice under PEG 8000-induced drought based on the leaf water content.  The results of this study  indicated that varieties factor (Superwin, Ombong, Burungan and Temo), the factor of PEG 8000 concentration (medium water potential -0.25 and -0.5 MPa),  the treatment period factor (0, 6 and 12 hours), the interaction between varieties and PEG 8000 concentration, interaction between varieties and treatment period, the interaction between PEG 8000 concentration and treatment period, interaction among varieties, PEG 8000 concentration and treatment period under drought did not result in significant differences in leaf water content. This study showed that leaf water content was not able to be the physiological indicator in these four North Sulawesi local rice varieties under drought.Keywords: Drought, PEG, leaf water content, North Sulawesi local rice

scholarly journals Respons tanaman kelapa sawit (Elaeis guineensis Jacq) terhadap cekaman kekeringan Respons of oil palm (Elaeis guineensis Jacq) to water stress

2016 ◽  
Vol 69 (2) ◽  
Author(s):  
Nurita TORUAN-MATHIUS ◽  
Gede WIJANA ◽  
Edi GUHARJA ◽  
Hajrial ASWIDINNOOR ◽  
Sudirman YAHYA ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Oil Palm ◽  
Glycine Betaine ◽  
Elaeis Guineensis ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Sds Page ◽  
Aba Content

SummaryWater stress affect many physiological andbiochemical processes of oil palm. A series ofexperiments were conducted to characterize thewater stress-induced changes in physiologicalrespons of oil palm to water stress, in glass housecondition. The experiment consisted of (1)permanent leaf wilting point measured based onsoil water content, leaf water content, specificleaf area and leaf water potential . Plants wereconducted by termination of watering to theplants, and control plants were maintained wellwatered during 0,3,6,9,12,15,18 and 21 days ofMK356 and MK365 clones. Experiment (2)effect of water stress on changes of leaf waterpotential, protein bands pattern, proline,glycine-betaine, osmotical sugar, and abcisicacid (ABA) of MK356 and MK365 clones.Water stress was induced by termination ofwatering to the plants and maintained wellwatered during 0, 7,14, and 18 days.Experiment (3) changes of protein bands patternby total protein and electrophoresis SDS-PAGEand SDS-PAGE 2D protein. of H2(D10DxD8D)x(L9TxL2T); H12 (D8D Self) x(L9T x L2T). H3 and H9 (BJ028D x BJ2117P)hybrids. H2 and H12, H3 and H9 potentiallytolerant and untolerant to water stress,respectively. The results showed that permanentwilting point reached in 18 days of water stress.Water stress caused the decreased soil watercontent, leaf water potential, leaf water content,relative leaf water content , and relative leafarea of two clones. Water potential, leaf watecontent dan relative leaf water content ofMK365 decrease faster compare with MK356.Soil water content sharply decrease after 6 hoursand in 18 days of water stress leaf waterpotential value < - 2.55 Mpa. Proline, glycine-betaine and glucose content were affect by waterstress. Interaction among water stress and cloneswere significantly appear in stachiose content.Leaf water potential values decrease, whereasproline, ABA and glycine-betaine contentsincrease during water stress especially inMK356. Generally showed that ABA content inMK356 higher than MK 365. The differencesresponses of MK356 with MK 365 obtained fromprolin,xylose and ABA content. Induction of newprotein pI 4.7-36 kDa, pI5.3-34 kDa, pI 4.6-32kDa and pI 5.3-36 kDa obtained from hybridspotentially tolerant to water strees, none inuntolerant hybrids.RingkasanCekaman kekeringan mempengaruhiproses fisiologis dan biokimia tanaman kelapasawit. Serangkaian percobaan bertujuan untukmengkarakterisasi perubahan fisiologis tanamankelapa sawit terhadap cekaman kekeringan,dalam kondisi rumah kaca telah dilakukan.Percobaan terdiri atas (1) penetapan titik layupermanen, berdasarkan perubahan potensial airdaun, kadar air daun, kadar air daun relatif, danluas daun relatif dengan perlakuan tanpa dandengan penyiraman selama 0, 3, 6, 9, 12, 15, 18dan 21 hari. Percobaan (2) penetapan perubahankadar prolin, glisin-betain, gula-gula osmotikaldan asam absisik (ABA), terhadap cekamankekeringan. Perlakuan adalah tanpa dan denganpenyiraman selama 0, 7, 14, dan 18 hari.Percobaan (3) analisis perubahan pola pita proteindaun hibrida H2 (D10DxD8D)x(L9TxL2T); H12(D8D Self) x (L9T x L2T). H3 dan H9 (BJ028Dx BJ2117P) terhadap cekaman kekeringan dengantotal protein, dan pola pita protein dengan SDSPAGE dan SDS-PAGE 2D. H2 dan H12 serta H3dan H9 masing-masing berpotensi toleran danpeka terhadap cekaman kekeringan. Hasil yangdiperoleh menunjukkan bahwa titik layupermanen dicapai pada hari ke 18 setelah dibericekaman kekeringan. Cekaman kekeringanmenurunkan kadar air tanah media tumbuh,potensial air daun, kadar air daun, kadar air daunrelatif, dan luas daun relatif untuk kedua klon.Potensial air daun, kadar air daun dan kadar airdaun relatif klon MK365 menurun lebih cepatdibandingkan dengan klon MK356. Kadar airtanah menurun tajam setelah 6 hari dibericekaman air dan potensial air daun mencapai<-2.55 MPa pada 18 hari setelah diberi cekaman.Cekaman kekeringan nyata berpengaruh terhadapkadar prolin, glisin betain dan glukosa. Interaksiantar lama cekaman kekeringan dan perbedaanklon diperoleh pada perubahan gula stahiosa.Tampak bahwa semakin menurun nilai potensialair daun menyebabkan kadar prolin semakinmeningkat. Hal yang sebaliknya terjadi terhadapkadar glisin-betain yang mengalami penurunanterutama untuk klon MK356. Kadar ABAMK356 dan MK365 meningkat sejalan dengansemakin lama diberi cekaman. Secara umumtampak bahwa kadar ABA pada MK356 lebihtinggi dibandingkan dengan MK 365. Perbedaanrespons klon MK356 dengan MK 365 terjadipada kadar prolin, gula silosa dan ABA.Hibridaberpotensi toleran memberikan respon terhadapcekaman kekeringan dengan menginduksi proteinbaru pI 4,7-36 kDa, pI5,3-34 kDa, pI 4,6-32 kDadan pI 5,3- 36 kDa, sedangkan pada hibridayang berpotensi peka protein tersebut tidakditemukan

LEAF WATER CONTENT AND POTENTIAL IN CORN, SORGHUM, SOYBEAN, AND SUNFLOWER

1974 ◽  
Vol 54 (1) ◽  
pp. 185-195 ◽  
Author(s):  
H. H. NEUMANN ◽  
G. W. THURTELL ◽  
K. R. STEVENSON ◽  
C. L. BEADLE
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Relative Water ◽  
Helianthus Annus ◽  
Glycine Max L ◽  
Water Contents

The Peltier-cooled thermocouple dewpoint hygrometer technique of in situ measurement of leaf water potential was further developed. The observed response of the instrument agreed so well with theoretical analysis that calibration based on theory was within 1% of that obtained using salt solutions of known water potential. Simultaneous measurements with the hygrometer and a beta gauge were made to derive the leaf water content–potential relationships for several crop plants. Results showed relative water contents dropping only to near 0.95 for mature corn (Zea mays L.); sorghum (Sorghum vulgare Pers.); and sunflower (Helianthus annus L.) leaves, and to 0.90 for not quite mature soybean (Glycine max (L.) Merr.) leaves as potentials declined from near −1 bar to the plant wilting point (−8 to −14 bars). Further decline of leaf water potential resulted in relatively much greater loss of leaf water.

scholarly journals Respons tanaman kelapa sawit (Elaeis guineensis Jacq) terhadap cekaman kekeringan Respons of oil palm (Elaeis guineensis Jacq) to water stress

2016 ◽  
Vol 69 (2) ◽  
Author(s):  
Nurita TORUAN-MATHIUS ◽  
Gede WIJANA ◽  
Edi GUHARJA ◽  
Hajrial ASWIDINNOOR ◽  
Sudirman YAHYA ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Oil Palm ◽  
Glycine Betaine ◽  
Elaeis Guineensis ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Sds Page ◽  
Aba Content

SummaryWater stress affect many physiological andbiochemical processes of oil palm. A series ofexperiments were conducted to characterize thewater stress-induced changes in physiologicalrespons of oil palm to water stress, in glass housecondition. The experiment consisted of (1)permanent leaf wilting point measured based onsoil water content, leaf water content, specificleaf area and leaf water potential . Plants wereconducted by termination of watering to theplants, and control plants were maintained wellwatered during 0,3,6,9,12,15,18 and 21 days ofMK356 and MK365 clones. Experiment (2)effect of water stress on changes of leaf waterpotential, protein bands pattern, proline,glycine-betaine, osmotical sugar, and abcisicacid (ABA) of MK356 and MK365 clones.Water stress was induced by termination ofwatering to the plants and maintained wellwatered during 0, 7,14, and 18 days.Experiment (3) changes of protein bands patternby total protein and electrophoresis SDS-PAGEand SDS-PAGE 2D protein. of H2(D10DxD8D)x(L9TxL2T); H12 (D8D Self) x(L9T x L2T). H3 and H9 (BJ028D x BJ2117P)hybrids. H2 and H12, H3 and H9 potentiallytolerant and untolerant to water stress,respectively. The results showed that permanentwilting point reached in 18 days of water stress.Water stress caused the decreased soil watercontent, leaf water potential, leaf water content,relative leaf water content , and relative leafarea of two clones. Water potential, leaf watecontent dan relative leaf water content ofMK365 decrease faster compare with MK356.Soil water content sharply decrease after 6 hoursand in 18 days of water stress leaf waterpotential value < - 2.55 Mpa. Proline, glycine-betaine and glucose content were affect by waterstress. Interaction among water stress and cloneswere significantly appear in stachiose content.Leaf water potential values decrease, whereasproline, ABA and glycine-betaine contentsincrease during water stress especially inMK356. Generally showed that ABA content inMK356 higher than MK 365. The differencesresponses of MK356 with MK 365 obtained fromprolin,xylose and ABA content. Induction of newprotein pI 4.7-36 kDa, pI5.3-34 kDa, pI 4.6-32kDa and pI 5.3-36 kDa obtained from hybridspotentially tolerant to water strees, none inuntolerant hybrids.RingkasanCekaman kekeringan mempengaruhiproses fisiologis dan biokimia tanaman kelapasawit. Serangkaian percobaan bertujuan untukmengkarakterisasi perubahan fisiologis tanamankelapa sawit terhadap cekaman kekeringan,dalam kondisi rumah kaca telah dilakukan.Percobaan terdiri atas (1) penetapan titik layupermanen, berdasarkan perubahan potensial airdaun, kadar air daun, kadar air daun relatif, danluas daun relatif dengan perlakuan tanpa dandengan penyiraman selama 0, 3, 6, 9, 12, 15, 18dan 21 hari. Percobaan (2) penetapan perubahankadar prolin, glisin-betain, gula-gula osmotikaldan asam absisik (ABA), terhadap cekamankekeringan. Perlakuan adalah tanpa dan denganpenyiraman selama 0, 7, 14, dan 18 hari.Percobaan (3) analisis perubahan pola pita proteindaun hibrida H2 (D10DxD8D)x(L9TxL2T); H12(D8D Self) x (L9T x L2T). H3 dan H9 (BJ028Dx BJ2117P) terhadap cekaman kekeringan dengantotal protein, dan pola pita protein dengan SDSPAGE dan SDS-PAGE 2D. H2 dan H12 serta H3dan H9 masing-masing berpotensi toleran danpeka terhadap cekaman kekeringan. Hasil yangdiperoleh menunjukkan bahwa titik layupermanen dicapai pada hari ke 18 setelah dibericekaman kekeringan. Cekaman kekeringanmenurunkan kadar air tanah media tumbuh,potensial air daun, kadar air daun, kadar air daunrelatif, dan luas daun relatif untuk kedua klon.Potensial air daun, kadar air daun dan kadar airdaun relatif klon MK365 menurun lebih cepatdibandingkan dengan klon MK356. Kadar airtanah menurun tajam setelah 6 hari dibericekaman air dan potensial air daun mencapai<-2.55 MPa pada 18 hari setelah diberi cekaman.Cekaman kekeringan nyata berpengaruh terhadapkadar prolin, glisin betain dan glukosa. Interaksiantar lama cekaman kekeringan dan perbedaanklon diperoleh pada perubahan gula stahiosa.Tampak bahwa semakin menurun nilai potensialair daun menyebabkan kadar prolin semakinmeningkat. Hal yang sebaliknya terjadi terhadapkadar glisin-betain yang mengalami penurunanterutama untuk klon MK356. Kadar ABAMK356 dan MK365 meningkat sejalan dengansemakin lama diberi cekaman. Secara umumtampak bahwa kadar ABA pada MK356 lebihtinggi dibandingkan dengan MK 365. Perbedaanrespons klon MK356 dengan MK 365 terjadipada kadar prolin, gula silosa dan ABA.Hibridaberpotensi toleran memberikan respon terhadapcekaman kekeringan dengan menginduksi proteinbaru pI 4,7-36 kDa, pI5,3-34 kDa, pI 4,6-32 kDadan pI 5,3- 36 kDa, sedangkan pada hibridayang berpotensi peka protein tersebut tidakditemukan

Plant Water Relation and Drought: Relationship Between Plant Water Potential and Relative Leaf Water Content in Different Tropical Plants

2020 ◽  
Author(s):  
Sydney Kerman ◽  
Kinzie Bailey ◽  
Joost van Haren ◽  
Angelika Kübert ◽  
Kathrin Kühnhammer ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Negative Relationship ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Plant Water ◽  
Long Term Effects ◽  
Tropical Plants ◽  
Plant Water Potential

&lt;p&gt;As global average temperature continues to increase and precipitation events become less predictable, understanding the long-term effects of drought on ecosystems is of increasing importance. However, it is difficult to study phenomena such as drought due to their unpredictable nature and the fact that it is difficult to tag and track the movement of water and carbon through an entire ecosystem. Within the framework of the controlled ecosystem manipulation experiment (WALD- Water, Atmosphere and Life Dynamics) at Biosphere 2, a deliberate drought in the enclosed tropical rainforest biome presented a unique opportunity to study responses in carbon and water cycling due to water stress. Within the scope of this study, the goal of this project was to examine the effect of prolonged water stress on different species within the rainforest and understand how the plants coped with the stress on an ecosystem level. This was accomplished by weekly plant water potential measurements (WP) before, during, and after the drought, as well as leaf sampling for relative leaf water content (RWC) and xylem sampling for water isotope measurements. For both predawn and midday WP, we found significantly different species responses; for &lt;em&gt;Ceiba pentandra&lt;/em&gt; and &lt;em&gt;Pachira aquatica&lt;/em&gt;, WP did not decrease during the drought, while for&lt;em&gt; Hibiscus tiliaceus&lt;/em&gt; and &lt;em&gt;Hibiscus rosa sinensis&lt;/em&gt;, WP decreased dramatically during the drought. After the additional of moisture from deeper depths, both &lt;em&gt;C. pentandra&lt;/em&gt; and &lt;em&gt;Hura crepitans&lt;/em&gt; (largest trees) responded the fastest by increasing in WP, while &lt;em&gt;H. tiliaceus&lt;/em&gt; and &lt;em&gt;H. rosa sinensis&lt;/em&gt; had the slowest recovery in WP, and only after rewetting from above had occurred. RWC also revealed different responses by different plant species, with &lt;em&gt;Phytolacca dioica&lt;/em&gt; and &lt;em&gt;H. rosa sinensis&lt;/em&gt; showing the highest RWC values throughout the experiment. The relationship between RWC and WP was also not consistent among species, with half of the species exhibiting a positive relationship, while the other half exhibiting a negative relationship. Other factors such as trunk capacitance and or leaf shedding during the drought might explain some of these contrasting relationships. Establishing such associations could lead to the development of tools that remotely assess average leaf water content of an area of forest via spectral reflectance and use those data to approximate the water stress of plants in that area, a very valuable asset when dealing with such geographically extensive phenomena as drought.&amp;#160;&lt;/p&gt;

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