scholarly journals Water stress-induced modifications of leaf hydraulic architecture in sunflower: co-ordination with gas exchange

2005 ◽  
Vol 56 (422) ◽  
pp. 3093-3101 ◽  
Author(s):  
Andrea Nardini ◽  
Sebastiano Salleo
1994 ◽  
Vol 24 (5) ◽  
pp. 954-959 ◽  
Author(s):  
L.J. Samuelson ◽  
J.R. Seiler

The interactive influences of ambient (374 μL•L−1) or elevated (713 μL•L−1) CO2, low or high soil fertility, well-watered or water-stressed treatment, and rooting volume on gas exchange and growth were examined in red spruce (Picearubens Sarg.) grown from seed through two growing seasons. Leaf gas exchange throughout two growing seasons and growth after two growing seasons in response to elevated CO2 were independent of soil fertility and water-stress treatments, and rooting volume. During the first growing season, no reduction in leaf photosynthesis of seedlings grown in elevated CO2 compared with seedlings grown in ambient CO2 was observed when measured at the same CO2 concentration. During the second growing season, net photosynthesis was up to 21% lower for elevated CO2-grown seedlings than for ambient CO2-grown seedlings when measured at 358 μL•L−1. Thus, photosynthetic acclimation to growth in elevated CO2 occurred gradually and was not a function of root-sink strength or soil-fertility treatment. However, net photosynthesis of seedlings grown and measured at an elevated CO2 concentration was still over 2 times greater than the photosynthesis of seedlings grown and measured at an ambient CO2 concentration. Growth enhancement by CO2 was maintained, since seedlings grown in elevated CO2 were 40% larger in both size and weight after two growing seasons.


1994 ◽  
Vol 86 (4) ◽  
pp. 625-636 ◽  
Author(s):  
L. H. Allen ◽  
R. R. Valle ◽  
J. W. Mishoe ◽  
J. W. Jones

2016 ◽  
Vol 34 (3) ◽  
pp. 329-335 ◽  
Author(s):  
Cristihian Jarri Bayona-Rodríguez ◽  
Iván Ochoa-Cadavid ◽  
Hernán Mauricio Romero

Elaeis guineensis palms and its interspecific hybrid (E. oleifera x E. guineensis) were planted in 2004 in the Cuernavaca farm of Unipalma S.A., located in the municipality of Paratebueno (Cundinamarca, Colombia). The palms were planted in two fields: Mecasaragua and Aurora. The first field has never been irrigated, and the second one (Aurora) has always been flood-irrigated during the dry season according to the parameters of the plantation. In this study, physiological parameters (gas exchange and water potential) were assessed in three seasons of the year 2013 (dry season, dry-to-wet transition season and wet season). Significant gas exchange differences were found among the seasons in the field with no irrigation (Mecasaragua). Likewise, differences between the genetic materials were observed during the dry season. For example, the photosyn thesis decreased by 75% compared with the palms planted in the irrigated field. No differences among seasons or materials were found in the irrigated field (Aurora). E. guineensis palms were more sensitive to water stress compared with the OxG interspecific hybrid. Both genetic materials responded rapidly to the first rains by leveling their photosynthetic rates and demonstrated an excellent capacity to recover from water stress.


2010 ◽  
Vol 40 (6) ◽  
pp. 1290-1294 ◽  
Author(s):  
Inês Cechin ◽  
Natália Corniani ◽  
Terezinha de Fátima Fumis ◽  
Ana Catarina Cataneo

The effects of water stress and rehydration on leaf gas exchange characteristics along with changes in lipid peroxidation and pirogalol peroxidase (PG-POD) were studied in mature and in young leaves of sunflower (Helianthus annuus L.), which were grown in a greenhouse. Water stress reduced photosynthesis (Pn), stomatal conductance (g s), and transpiration (E) in both young and mature leaves. However, the amplitude of the reduction was dependent on leaf age. The intercellular CO2 concentration (Ci) was increased in mature leaves but it was not altered in young leaves. Instantaneous water use efficiency (WUE) in mature stressed leaves was reduced when compared to control leaves while in young stressed leaves it was maintained to the same level as the control. After 24h of rehydration, most of the parameters related to gas exchange recovered to the same level as the unstressed plants except gs and E in mature leaves. Water stress did not activated PG-POD independently of leaf age. However, after rehydration the enzyme activity was increased in mature leaves and remained to the same as the control in young leaves. Malondialdehyde (MDA) content was increased by water stress in both mature and young leaves. The results suggest that young leaves are more susceptible to water stress in terms of gas exchange characteristics than mature leaves although both went through oxidative estresse.


1999 ◽  
Vol 26 (2) ◽  
pp. 115 ◽  
Author(s):  
Maurizio Mencuccini ◽  
Jonathan Comstock

In a greenhouse study, 12 common bean cultivars from a wide geographical range were compared for their morphological, gas exchange and hydraulic architecture characters. Cultivars bred for cultivation in hot and dry regions had significantly smaller leaves and crowns, but higher stomatal conductances and transpiration rates per unit of leaf area. Short-term variability in gas exchange rates was confirmed using leaf carbon isotope discrimination. A literature survey showed that, although previously unnoticed, the strong inverse coupling between leaf size and gas exchange rates was present in three other studies using the same set of cultivars. Several measures of ‘leaf-specific hydraulic conductance’ (i.e. for the whole plant and for different parts of the xylem pathway) were also linearly related to rates of water loss, suggesting that the coupling between leaf size and gas exchange was mediated by a hydraulic mechanism. It is possible that breeding for high production in hot regions has exerted a selection pressure to increase leaf-level gas exchange rates and leaf cooling. The associated reductions in leaf size may be explained by the need to maintain equilibrium between whole-plant water loss and liquid-phase hydraulic conductance.


2019 ◽  
Vol 14 (3) ◽  
pp. 133-141
Author(s):  
Anna Rita Rivelli ◽  
Susanna De Maria

Horseradish (Armoracia rusticana) is a perennial plant, belonging to the Brassicaceae family, whose roots are widely used as a cooking spice and flavouring agent across the world and has recently acquired considerable scientific interest due to the richness of phytochemicals. Aim of the study was to explore water relations in plants grown in pots and subject to severe stress conditions and gas exchange, plant growth, and agronomic characteristics of two horseradish accessions grown in open field under rainfed Mediterranean conditions. Total and osmotic leaf water potential were significantly reduced by water stress to a similar extent at predawn and middle day. The carbon isotope composition (δ13C) (on average –34.2 and –28.9‰ in leaves and roots, respectively) resulted statistically different among water stress treatments in leaves collected at middle day. In open field, during the vegetative development, plants regulate the foliage expansion depending on rainfall distribution and temperature. When the dry period occurs, plants get rid of several mature leaves that dry completely, and might develop new leaves in the next period, when the air-cools and rainfall increases. During the dry period, horseradish optimised gas exchange during the day by increasing the net CO2 assimilation rate during the early morning (up to 31 μmol CO2 m–2s–1, on average), when the sunlight intensity and the air temperature conditions are more favourable. The species, which rely on an annual rainfall of about 680 mm, produced about 11.5 and 24.3 t/ha of roots from one- and two-year-old plantations, respectively. Regardless of accessions, close relationships were found between the number of leaves and root weight (R2=0.88 and P≤0.01) and diameter (R2=0.82 and P≤0.01). The results advise the importance to know the physiology and agronomic characteristics of horseradish to purposefully apply agronomic practices and strategies to maximise benefits for production and root quality.


Crop Science ◽  
1996 ◽  
Vol 36 (4) ◽  
pp. 922-928 ◽  
Author(s):  
K. L. Faver ◽  
T. J. Gerik ◽  
P. M. Thaxton ◽  
K. M. El‐Zik

2016 ◽  
Vol 40 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Maria da Assunção Machado Rocha ◽  
Claudivan Feitosa de Lacerda ◽  
Marlos Alves Bezerra ◽  
Francisca Edineide Lima Barbosa ◽  
Hernandes de Oliveira Feitosa ◽  
...  

ABSTRACT The low availability of water in the soil is one of the limiting factors for the growth and survival of plants. The objective of this study was to evaluate the responses of physiological processes in early growth of guanandi (Calophyllum brasilense Cambess), African mahogany (Khayai vorensis A. Chev) and oiti (Licaniato mentosa Benth Fritsch) over a period of water stress and other of rehydration in the soil with and without addition of organic matter. The study was conducted in a greenhouse and the experimental design was completely randomised into a 3 x 2 x 2 factorial scheme, comprising three species (guanandi, African mahogany, and oiti), two water regimes (with and without water restriction) and two levels of organic fertilisation (with and without the addition of organic matter). Irrigation was suspended for 15 days in half of the plants, while the other half (control) continued to receive daily irrigation, the soil being maintained near field capacity for these plants. At the end of the stress period, the plants were again irrigated for 15 days to determine their recovery. Water restriction reduced leaf water potential and gas exchange in the three species under study, more severely in soil with no addition of organic matter. The addition of this input increased soil water retention and availability to the plants during the suspension of irrigation, reducing the detrimental effects of the stress. During the period of rehydration, there was strong recovery of water status and leaf gas exchange. However recovery was not complete, suggesting that some of the effects caused by stress irreversibly affected cell structures and functions. However, of the species being studied, African mahogany displayed a greater sensitivity to stress, with poorer recovery.


2017 ◽  
Vol 45 (1) ◽  
pp. 238-244 ◽  
Author(s):  
Udson de Oliveira BARROS JUNIOR ◽  
Maria Antonia Machado BARBOSA ◽  
Michael Douglas Roque LIMA ◽  
Gélia Dinah Monteiro VIANA ◽  
Allan Klynger da Silva LOBATO

Low water supply frequently interferes on chlorophyll fluorescence and gas exchange. This study aimed to answer if a short-time of rehydration is efficient to re-establish chlorophyll fluorescence and gas exchange in cowpea plants. The experiment used four treatments (sensitive / water deficit, sensitive / control, tolerant / water deficit and tolerant / control). The sensitive and tolerant cultivars after water restriction had significant changes in gas exchange. On the third day, the stress caused lower for PN and gs in sensitive cultivar of 67% and 45%, respectively. After rehydration these parameters were not recovered significantly to two cultivars. In relation to chlorophyll fluorescence, water stress caused significant changes in all parameters evaluated of cultivars, being observed effects more intense on sensitive cultivar in the parameters Fv/Fm (38%) and Fo (69%). Rehydration did not promote recovery of the values of Fv/Fm and Fo to sensitive cultivar. Therefore, our study revealed that a short-time of rehydration is not effective to re-establish chlorophyll fluorescence and gas exchange in cowpea plants submitted to water deficit.


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