The diurnal course of leaf gas exchange of the C4 species Amaranthus retroflexus under field conditions in a ?cool? climate: Comparison with the C3 species Glycine max and Chenopodium album

Relatively pure stands of eight weed species were maintained under field conditions on a Goldsboro loamy sand at Lewiston, North Carolina, for all or part of a 6-year period. Herbicides evaluated as preemergence surface treatments for these species were 2-sec-butyl-4,6-dinitrophenol (dinoseb), isopropyl m-chlorocarbanilate (chloropropham), 3-(3,4-dichlorophenyl)-1,1-dimethyl-urea (diuron), 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), and 3-amino-2,5-dichlorobenzoic acid (amiben). S-ethyl dipropylthiocarbamate (EPTC) and a,a,a-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) were evaluated as preemergence incorporated treatments. The first four herbicides were evaluated in 1961, 1964, and 1966 while the last three were evaluated in 1962, 1963, and 1965. A series of rates was used for each chemical with three replications. With the exception of diuron which failed to control goosegrass (Eleusine indica (L.) Gaertn.), all of the herbicides provided at least a moderate degree of control of goosegrass, smooth crabgrass (Digitaria ischaemum (Schreb.) Muhl.), and redroot pigweed (Amaranthus retroflexus L.) at the respective typical field use rates. In general, trifluralin and amiben gave the best grass control and dinoseb the poorest. None of the herbicides effectively controlled common cocklebur (Xanthium pensylvanicum Wallr.) or ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.). Trifluralin and EPTC did not control Pennsylvania smartweed (Polygonum pensylvanicum L.), common ragweed (Ambrosia artemisiifolia L.), and common lambsquarters (Chenopodium album L.). Chloropropham was ineffective on common ragweed. Simazine, chloropropham, and amiben controlled Pennsylvania smartweed while diuron, simazine, dinoseb, and amiben were especially effective on common lambsquarters. Distinctive patterns of nematode infestations were observed as a function of weed species.

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The Effect of CO2 Enrichment and Irradiance on the Growth, Morphology and Gas Exchange of a C3 (Panicum laxum) and a C4 (Panicum antidotale) Grass

Functional Plant Biology ◽

10.1071/pp96077_co ◽

1997 ◽

Vol 24 (3) ◽

pp. 407 ◽

Cited By ~ 3

Author(s):

Oula Ghannoum ◽

Susanne von Caemmerer ◽

Edward W. R. Barlow ◽

Jann P. Conroy

Keyword(s):

Gas Exchange ◽

Co2 Enrichment ◽

Fold Increase ◽

Dry Weight ◽

Co2 Concentration ◽

High Light ◽

High Co2 ◽

Low Co2 ◽

C4 Species ◽

C3 Species

The effect of CO2 enrichment and irradiance on the growth and gas exchange of two tropical grasses, Panicum laxum (C3) and Panicum antidotale (C4) were investigated. The two species were grown at either 350 (low) or 700 (high) µL L-1 CO2 concentration, under 40% (low) or 100% (high) of direct sunlight and supplied with ample water and nutrition. Elevated CO2 enhanced plant dry weight at both irradiances in the C3 species (1.41-fold and 1.71-fold increase at low and high light, respectively) but only at high light in the C4 species (1.28 fold increase). CO2 enrichment had no effect on the dry weight of P. antidotale, when stem development was suppressed by growth under artificial lighting. When measured at the CO2 concentration at which they were grown, assimilation rates were similar in the low and high CO2 grown plants, for both species. However, when measurements made at low CO2 were compared, CO2 assimilation rates of the high light, high CO2 grown C3 and C4 species were lower than those of their low CO2 grown counterparts. High CO2 strongly reduced the stomatal conductance of both species, while it affected the Rubisco content (30% decrease) of the high light C3 species only. This work shows clearly that C4 species can respond to CO2 enrichment under favourable growth conditions, and that acclimation to elevated CO2 in pasture grasses does not necessarily involve accumulation of non-structural carbohydrates or reduction of total N or soluble proteins in source leaves.

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Effects of water vapor pressure difference on leaf gas exchange in potato and sorghum at ambient and elevated carbon dioxide under field conditions

Field Crops Research ◽

10.1016/s0378-4290(03)00004-2 ◽

2003 ◽

Vol 82 (1) ◽

pp. 37-47 ◽

Cited By ~ 25

Author(s):

James A. Bunce

Keyword(s):

Carbon Dioxide ◽

Water Vapor ◽

Gas Exchange ◽

Vapor Pressure ◽

Pressure Difference ◽

Leaf Gas Exchange ◽

Water Vapor Pressure ◽

Elevated Carbon Dioxide ◽

Field Conditions ◽

Vapor Pressure Difference

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IMPROVING THE DEVELOPMENT OF COFFEA ARABICA AFTER CHANGING THE PATTERN OF LEAF GAS EXCHANGE BY WATERING CYCLES

Experimental Agriculture ◽

10.1017/s0014479710000013 ◽

2010 ◽

Vol 46 (3) ◽

pp. 381-391 ◽

Cited By ~ 2

Author(s):

PAULA NOVAES ◽

JOÃO PAULO SOUZA ◽

CARLOS HENRIQUE BRITTO ASSIS PRADO

Keyword(s):

Gas Exchange ◽

Coffea Arabica ◽

Leaf Gas Exchange ◽

Net Photosynthesis ◽

Area Ratio ◽

Field Conditions ◽

Initial Growth ◽

Initial Development ◽

Vegetative And Reproductive Growth ◽

Flowering Intensity

SUMMARYHardening of Coffea arabica saplings by watering cycles (WCs) might be a suitable practice to achieve higher tolerance to low leaf water potential (Ψleaf) before transplanting to the field. As a consequence, hardening could promote growth and biomass gain during the initial development of C. arabica in the field. Thus, the less interrupted initial growth in a changing environment should confer higher flowering intensity in hardened than in control plants. The aim of this work was to verify if leaf gas exchange and Ψleaf behaviour of C. arabica saplings grafted on C. canephora showed consistent alterations during hardening by WCs and if this was effective to improve vegetative and reproductive growth under field conditions. For these reasons, saplings of the Mundo Novo cultivar of C. arabica grafted on C. canephora were submitted to seven WCs over 35 days. Each WC was completed when net photosynthesis was close to zero. The pattern of leaf gas exchange, mainly stomatal conductance (gs), was modified permanently after three WCs and the new pattern of leaf gas exchange could result in a more positive water balance and less interrupted development of C. arabica saplings in the field, particularly due to permanent low values of gs. After field transplantation, hardened plants showed greater height and stem diameter, more leaves and branches, and superior biomass production in leaves, stem and roots than control plants in dry and wet periods. The number of flowers was also significantly higher in hardened than in control plants. On the other hand, similar values were found between control and hardened plants in the leaf area ratio and the shoot/root ratio. Therefore, previous hardening by WCs was effective in improving leaf gas exchange, vegetative and reproductive development under field conditions and maintained the original biomass partitioning among the main plant compartments in dry and wet periods.

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The Effect of CO2 Enrichment and Irradiance on the Growth, Morphology and Gas Exchange of a C3 (Panicum laxum) and a C4 (Panicum antidotale) Grass

Functional Plant Biology ◽

10.1071/pp96077 ◽

1997 ◽

Vol 24 (2) ◽

pp. 227 ◽

Cited By ~ 50

Author(s):

Oula Ghannoum ◽

Susanne von Caemmerer ◽

Edward W. R. Barlow ◽

Jann P. Conroy

Keyword(s):

Gas Exchange ◽

Co2 Enrichment ◽

Fold Increase ◽

Dry Weight ◽

Co2 Concentration ◽

High Light ◽

High Co2 ◽

Low Co2 ◽

C4 Species ◽

C3 Species

The effect of CO2 enrichment and irradiance on the growth and gas exchange of two tropical grasses, Panicum laxum (C3) and Panicum antidotale (C4) were investigated. The two species were grown at either 350 (low) or 700 (high) µL L-1 CO2 concentration, under 40% (low) or 100% (high) of direct sunlight and supplied with ample water and nutrition. Elevated CO2 enhanced plant dry weight at both irradiances in the C3 species (1.41-fold and 1.71-fold increase at low and high light, respectively) but only at high light in the C4 species (1.28 fold increase). CO2 enrichment had no effect on the dry weight of P. antidotale, when stem development was suppressed by growth under artificial lighting. When measured at the CO2 concentration at which they were grown, assimilation rates were similar in the low and high CO2 grown plants, for both species. However, when measurements made at low CO2 were compared, CO2 assimilation rates of the high light, high CO2 grown C3 and C4 species were lower than those of their low CO2 grown counterparts. High CO2 strongly reduced the stomatal conductance of both species, while it affected the Rubisco content (30% decrease) of the high light C3 species only. This work shows clearly that C4 species can respond to CO2 enrichment under favourable growth conditions, and that acclimation to elevated CO2 in pasture grasses does not necessarily involve accumulation of non-structural carbohydrates or reduction of total N or soluble proteins in source leaves.

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