scholarly journals SALINITY AFFECTS GROWTH AND NET GAS EXCHANGE OF CARAMBOLA

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1136d-1136
Author(s):  
Thomas E. Marler

Salinity effects on growth and net gas exchange of carambola (Averrhoa carambola L.) examined in were greenhouse culture with ten-month-old seedlings in perlite: peat: sand: pine bark chip medium in 5.1 liter (21 cm top dia.) containers. Treatments of 0.05, 5.1, 9.5, or 13.9 dS·m-1 were obtained by dissolving ca. 0, 2.5, 5.0, or 7.5 g of dehydrated sea salt per liter of rain water and delivered from elevated tanks by gravity to dribble ring emitters in containers via polyethylene and q icro tubing. All plants except control plants received 5.1 dS·m-1 beginning 25 Nov., and concentration was gradually increased for the two highest salinity levels until reaching 9.5 dS·m-1 on 3 Dec. and 13.9 dS·m-1 on 7 Dec. Plants were watered twice weekly until 1 March 1990. Stomatal conductance was determined (LI-COR 1600 steady-state diffusion porometer) on 7 day intervals beginning 24 Nov. Growth was determined as leaf area (LI-COR 3000 area meter), plant dry weight, and trunk diameter. Stomatal conductance declined in all salinity levels to 50% or less of controls by day 12, with a gradual further decline thereafter. Leaf area, plant dry weight, and trunk diameter declined linearly with increased salinity.

Author(s):  
Henderson C. Sousa ◽  
Geocleber G. de Sousa ◽  
Carla I. N. Lessa ◽  
Antonio F. da S. Lima ◽  
Rute M. R. Ribeiro ◽  
...  

ABSTRACT The excess of salts can affect several processes in the crops, and nitrogen (N) can attenuate the depressive effect of salinity. The objective was to evaluate the influence of nitrogen doses on the growth and gas exchange of corn crop irrigated with saline water. The experiment was conducted from June to September 2019 at the University of International Integration of Afro-Brazilian Lusophony, Redenção, CE, Brazil. The experimental design was completely randomized, in a 2 x 3 factorial scheme (supply water of 0.3 dS m-1 and saline solution of 3.0 dS m-1) and three nitrogen doses, 0, 80, and 160 kg ha-1, corresponding to 0, 50, and 100% of the recommended dose respectively, with six repetitions. At 30 and 45 days after sowing (DAS), plant height, leaf area, number of leaves, photosynthesis, transpiration, and stomatal conductance were evaluated. Saline stress affects plant height, leaf area, photosynthesis, transpiration, and conductance at 30 DAS. The doses of 80 and 160 kg ha-1 provide greater performance in plant height, leaf area, photosynthesis, transpiration, and conductance at 30 DAS. The use of low salinity water and doses of 80 and 160 kg ha-1 were more efficient in terms of plant height, leaf area, photosynthesis, transpiration, and conductance at 45 DAS. The dose of 160 kg ha-1 of N attenuates the harmful effects of salts in AG 1051 hybrid maize plants, providing higher values of photosynthesis, transpiration, and stomatal conductance at 45 DAS when irrigated with water of 3.0 dS m-1.


2014 ◽  
Vol 32 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Lindsey Fox ◽  
Amber Bates ◽  
Thayne Montague

For three growing seasons (2003–2005) two newly planted, field-grown redbud (Cercis canadensis L.) varieties were subjected to three reference evapotranspiration (ETo)-based irrigation regimes (100, 66, and 33% ETo). Over this time period, water relations (pre-dawn leaf water potential), gas exchange (mid-day stomatal conductance), and growth data (trunk cross sectional area increase, tree leaf area, and shoot elongation) were measured. Pre-dawn leaf water potential (ψl) was more negative for trees receiving the least amount of irrigation, and for Mexican redbud [C. canadensis var. mexicana (Rose) M. Hopkins] trees. However, mid-day stomatal conductance (gs) was similar for Texas redbud (C. canadensis var. texensis S. Watson) trees across the three irrigation regimes, and was highest for Mexican redbud trees receiving the greatest amount of irrigation volume. Growth varied by variety and irrigation regime. Trunk cross sectional area increase was greatest for Mexican redbud trees, leaf area was highest for trees receiving the greatest amount of irrigation, and shoot elongation was greatest for trees receiving the 66% ETo irrigation regime. However, despite differing irrigation volumes, greatest gas exchange and growth was not necessarily associated with greatest irrigation volume. When considering conservation of precious water resources, these redbud varieties maintain adequate growth and appearance under reduced irrigation.


2017 ◽  
Vol 47 (3) ◽  
pp. 345-352
Author(s):  
Álvaro Henrique Cândido de Souza ◽  
Roberto Rezende ◽  
Marcelo Zolin Lorenzoni ◽  
Fernando André Silva Santos ◽  
André Maller

ABSTRACT Adequate crop fertilization is one of the challenges for agriculture. Measuring gas exchange and biomass accumulation may be used to adjust crop management. The effect of fertigation with potassium (0 kg ha-1, 54 kg ha-1, 108 kg ha-1 and 216 kg ha-1) and nitrogen (0 kg ha-1, 67 kg ha-1, 134 kg ha-1 and 268 kg ha-1) on gas exchange and biomass accumulation in eggplant was assessed under greenhouse conditions. The net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, instantaneous carboxylation efficiency, water-use efficiency and total dry weight were evaluated. With the exception of K for water-use efficiency and N for internal CO2 concentration, all the other gas exchange parameters were significantly affected by the K and N doses. There was an interaction between N and K doses for net photosynthesis, stomatal conductance, transpiration and instantaneous carboxylation efficiency. The highest values for net photosynthesis, stomatal conductance, transpiration rate, carboxylation instantaneous efficiency and total dry weight were found in the range of 125-185 kg ha-1 of K and 215-268 kg ha-1 of N.


2004 ◽  
Vol 61 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Paulo Torres Carneiro ◽  
Pedro Dantas Fernandes ◽  
Hans Raj Gheyi ◽  
Frederico Antônio Loureiro Soares ◽  
Sergio Batista Assis Viana

The cashew crop (Anacardium occiedentale L.) is of great economic and social importance for Northeast Brazil, a region usually affected by water and soil salinity. The present study was conducted in a greenhouse to evaluate the effects of four salinity levels established through electrical conductivity of irrigation water (ECw: 0.7, 1.4, 2.1 and 2.8 dS m-1, at 25ºC), on growth and physiological indexes of five rootstocks of dwarf-precocious cashew varieties CCP06, CCP09, CCP1001, EMBRAPA50, and EMBRAPA51. Plant height, leaf area, dry weight of root, shoot and total; water content of leaves, root/shoot ratio, leaf area ratio, absolute and relative growth rates and rate of net assimilation were evaluated. The majority of the evaluated variables were found to be affected by ECw and the effects varied among clones; however, no significant interactive effects were observed for factors. The value of ECw = 1.39 dS m-1 was considered as a threshold tolerance for the precocious cashew rootstocks used in this study. The dwarf-precocious cashew is moderately sensible to soil salinity during the formation phase of rootstock. Clones EMBRAPA51 and EMBRAPA50 presented, respectively, the least and the best development indexes.


2000 ◽  
Vol 80 (4) ◽  
pp. 841-847 ◽  
Author(s):  
Jean-Pierre Privé ◽  
N. Allain

Four primocane-fruiting (PF) red raspberry cultivars, Bogong, Autumn Cascade, Heritage and Dinkum, were grown in exposed or sheltered (50% permeable artificial windbreak) sites fully exposed to prevailing winds in Bouctouche, NB. Shelters were erected at the beginning and removed at the end of each growing season. In the establishment year, all cultivars were evaluated to determine the effects of wind stress on their vegetative and reproductive development and leaf gas exchange. since all cultivars responded similarly to the effect of wind in year one, only Dinkum was monitored in years two and three. In all years, the artificial windbreak resulted in an overall 35% reduction in wind velocity, increased the number of calm days (<5.4 km h−1) and decreased the incidence of strong breezes (>36 km h−1). Interestingly in this maritime climate, the artificial windbreak did not have much of an effect on altering relative humidity, vapour pressure deficits, or air or soil temperature. Plants from sheltered sites consistently had greater above-ground biomass (especially cane dry weight) and longer cane internodes. For two of the three years, leaf area and yield were also greater in the sheltered sites. Leaf gas exchange parameters (Pn, gs and Ci), expressed per unit of leaf area, did not differ between treatments for most of the season, but the sheltered plants retained more leaf area and thus had the potential to fix a greater amount of carbon than the exposed plants. The larger, sheltered plants produced a more extensive fruiting framework, which resulted in increased yields in both the establishment and subsequent year. It is recommended to shelter raspberry plants from wind in the initial establishment years. Key words: Rubus idaeus L., fall-bearing, autumn fruiting, windbreak


1988 ◽  
Vol 6 (3) ◽  
pp. 96-100 ◽  
Author(s):  
S.E. Newman ◽  
M.W. Follett

Trickle irrigation frequency, shading, water relations, and plant growth of container-grown Euonymus japonica Thunb. ‘Aureomarginata’ was investigated. Plants were grown under a combination of 3 irrigation frequencies and 2 shade levels. Stomatal conductance (gs) was reduced when plants were irrigated 3 times per week compared to irrigation daily and twice daily after week 4 under full sun and after week 8 under shade. Few differences were detected in predawn shoot water potential (Ψshoot) under shade at any irrigation level. The predawn shoot water potential (Ψshoot) was reduced (rnore negative) for plants irrigated 3 times per week compared to irrigation daily and twice daily after week 8 for plants grown under full sun and week 10 for plants grown under shade. These values remained lower for the duration of the study. Plants grown under shade and irrigated once daily had greater plant dry weight and leaf area compared to plants irrigated either twice daily or 3 times per week. They were also larger than all plants grown under full sun. Plants grown under shade had greater chlorophyll levels per unit leaf area. Under shade, plant quality was not affected by irrigation rates. However, only plants grown under shade were of salable quality.


1991 ◽  
Vol 9 (3) ◽  
pp. 163-167
Author(s):  
Stuart L. Warren ◽  
Frank A. Blazich ◽  
Mack Thetford

Abstract Uniconazole was applied as a foliar spray or medium drench to six woody landscape species: ‘Sunglow’ azalea; flame azalea; ‘Spectabilis’ forsythia; ‘Compacta’ holly; ‘Nellie R. Stevens’ holly; and mountain pieris. One hundred days after uniconazole application, leaf, stem, and top dry weight of all species, except flame azalea and mountain pieris, decreased as uniconazole concentration increased. Compared to controls, stem and leaf dry weight were reduced by uniconazole 18 to 60% and 13 to 32%, respectively, depending on species and method of application. Stem dry weight was reduced to a greater degree, compared to leaf dry weight. For all species, drench application was more effective than foliar spray in reducing leaf, stem, and top dry weight. Leaf area of ‘Spectabilis’ forsythia and ‘Nellie R. Stevens’ holly decreased with increasing rates. However, specific leaf weight was not affected. Uniconazole did not significantly affect leaf net photosynthetic rate, stomatal conductance or internal leaf CO2 concentrations in ‘Spectabilis’ forsythia or ‘Nellie R. Stevens’ holly. No phytotoxicity was observed on any species.


2020 ◽  
Vol 48 (2) ◽  
pp. 1027-1042
Author(s):  
Éva ÓNODY ◽  
Károly HROTKÓ ◽  
Magdolna SÜTÖRINÉ DIÓSZEGI

The pot in pot (PIP) system is a new alternative to container above ground (CAG) cultivation in nurseries. Our study estimates plant water usage of plants in CAG and PIP. Main variables as plant species, nursery container type and year effect on morphological parameters (plant size, leaf area, fresh and dry weight), on daily water use (weighed DWU), transpiration of leaves (DT) supplemented with species effect were analysed. Twenty plants grown in 5 L plastic pots of each combination were investigated. For leaf area measurement by AM350 we sampled 30 leaves from each plant. Fourty plants were weighed by a digital scale (Dyras, KSCL-300), morning and evening on each sampling day. Leaf gas exchange was measured on the same days by using leaf gas exchange analyzer (LCi, ADC Scientific Ltd.). From the two investigated deciduous (tatarian dogwood) and evergreen species (cherry laurel), only the tatarian dogwood showed improved quality in the PIP system (enhanced canopy increment, fresh and dry weight).  Significant difference showed the two species in DWU, and in DT. The tatarian dogwood used 626 g day-1 water (194 %) compared to the cherry laurel’s 341 g day-1 water use in 2015, while in 2016 this ratio was 144% in favor of tatarian dogwood. We measured higher initial morning weight (IWC) in PIP system. The transpiration measurements on single selected leaves overestimated the real transpiration compared to DWU. The DT of the deciduous tatarian dogwood responses more sensitive to environmental conditions than the evergreen cherry laurel.


HortScience ◽  
1992 ◽  
Vol 27 (8) ◽  
pp. 913-915 ◽  
Author(s):  
Thomas E. Marler ◽  
Yasmina Zozor

Growth and leaf gas-exchange responses of carambola (Averrhoa carambola L.) seedlings to wind or seismic stress were studied under glasshouse conditions. Forty days of twice daily seismic stress applied for 10 seconds consistently reduced carambola height, leaf area, dry weight, relative growth rate, and leaf-area ratio, but increased trunk cross-sectional area compared with plants receiving no seismic stress. Fifty-one days of wind load reduced plant height, leaf area, dry weight, trunk cross-sectional area, net assimilation rate, relative growth rate, leaf-area ratio, and stomatal conductance compared with plants receiving no wind stress. Morphological appearance was similar for plants receiving wind or seismic stress. Net CO2 assimilation of carambola leaflets was reduced by 30 minutes of wind load for up to 6 hours following the stress. Results suggest that wind may reduce carambola growth at least partially by influencing leaf gas exchange or by the mechanical stress associated with wind.


2000 ◽  
Vol 125 (2) ◽  
pp. 228-234 ◽  
Author(s):  
J.P. Syvertsen ◽  
L.S. Lee ◽  
J.W Grosser

Diploid (2x) and autotetraploid (4x) Citrus L. rootstock cultivars were grown at elevated CO2 to obtain insights into limitations on growth and net gas exchange that have been associated with tetraploidy. Well-nourished 2x and 4x seedlings of `Volkamer' lemon (Volk, C. volkameriana Ten & Pasq.), `Troyer' citrange [Troy, C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.] and `Cleopatra' mandarin (Cleo, C. reticulata Blanco.), were grown in greenhouses at either ambient or twice ambient CO2 for 4 months. Plant growth, water relations, mineral nutrition, and net gas exchange characteristics of leaves were measured. Most 4x plants were smaller and had lower rates of whole plant transpiration but shorter fibrous roots than 2x plants. Fibrous roots of 4x were thicker than 2x roots as indicated by a lower specific root length (SRL) in 4x than in 2x roots. Root hydraulic conductivity was correlated to total plant growth but there were no effects of CO2 or ploidy on root conductivity. Tetraploid leaves had lower N concentrations than 2x leaves when expressed on a dry weight basis but these differences disappeared when N concentration was expressed on an leaf area basis because 4x leaves had more leaf dry weight per area (LDW/a) than 2x leaves. Plant growth was greater and SRL was lower at elevated CO2 than at ambient CO2. LDW concentrations of N, P, and K were lower at elevated CO2 than at ambient apparently due to a growth dilution effect. LDW/a, net CO2 assimilation (ACO2), and leaf water use efficiency were greater at elevated CO2 than at ambient. Overall, there was no effect of ploidy on ACO2 but 4x Volk and Troy had lower rates of ACO2 than their 2x at elevated CO2. Net gas exchange of tetraploid leaves was less responsive to elevated CO2 than 2x leaves. The low SRL of tetraploids was correlated with low whole plant transpiration rates and low leaf area-based N concentrations, which may be operative in determining the growth characteristics associated with tetraploidy.


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