Gas Exchange Characteristics of Apple at Various Light Intensities under Two Levels of European Red Mite Damage

Single leaf gas exchange measurements were taken at a range of light intensities from 20 to 1500 μmol·m-2·s-1 PAR under greenhouse conditions on `Washington Spur'/EMLA seven potted apple trees subjected to either 1500 cumulative mite days (CMD) European Red mite (ERM) damage or no mite damage. 1500 CMD ERM damage significantly reduced assimilation (A) over all light intensities for leaves present during mite damage at 6 days after the mite population had reached the 1500 CMD level and the mites were killed. Mite damage did not significantly affect A of either leaves present during mite damage or leaves produced after the mites were killed on any other sampling date. However, a trend of reduced A of leaves present during mite infestation on the mite-damaged trees was apparent on all sampling dates after the mites were killed. Evapotranspiration (E) was not affected by mite damage. The mite damage by light intensity interaction did not have a significant effect on A or E on any sampling date.

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ABA, Hydraulics, and Gas Exchange of Split-rooted Apple Trees

HortScience ◽

10.21273/hortsci.40.4.1097c ◽

2005 ◽

Vol 40 (4) ◽

pp. 1097C-1097

Author(s):

Todd C. Einhorn ◽

Horst W. Caspari ◽

Steve Green

Keyword(s):

Gas Exchange ◽

Time Domain ◽

Sap Flow ◽

Leaf Gas Exchange ◽

Heat Pulse ◽

Time Domain Reflectometry ◽

Apple Trees ◽

Pulse Technique ◽

Predawn Leaf Water Potential ◽

Single Leaf

Approach-grafted 1-year-old `Gala'/M7 apple trees were grown with both tops for the remainder of the 2003 season in a greenhouse. Trees were supplied with >100% (control, PRD100) or 50% (PRD50, DI50) of daily ETc either applied to one root compartment only (PRD100, PRD50) or divided evenly across both root compartments (control and DI50). ETc was estimated from gravimetric measurements, and irrigation was switched between wet and dry root compartments several times throughout the experiment. Soil moisture was measured both gravimetrically (tripod) and volumetrically (time-domain reflectometry). Predawn leaf water potential (υpd) and single leaf gas exchange (photosynthesis, stomatal conductance, and transpiration) were recorded daily, and sap flow in stems and roots was monitored continuously using the heat-pulse technique. Leaves were collected for abscisic acid (ABA) determination following gas exchange measurements. Regardless of irrigation placement (i.e., PRD or DI), both 50% ETc treatments experienced similar declines in υpd and single leaf gas exchange relative to control levels. In addition, ABA concentrations were similar for PRD50 and DI50, and were significantly higher than the control and PRD100 treatments. PRD100 trees had similar υpd as control trees; however, gas exchange was reduced >25% compared to the control. Bulk leaf ABA concentration did not differ significantly from control levels and does not by itself explain the down regulation of stomata with PRD100.

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LEAF GAS EXCHANGE CHARACTERISTICS OF FOUR PAPAYA GENOTYPES DURING DIFFERENT STAGES OF DEVELOPMENT

Revista Brasileira de Fruticultura ◽

10.1590/s0100-29452001000300014 ◽

2001 ◽

Vol 23 (3) ◽

pp. 522-525 ◽

Cited By ~ 6

Author(s):

ELIEMAR CAMPOSTRINI ◽

OSVALDO KIYOSHI YAMANISHI ◽

CARLOS A. MARTINEZ

Keyword(s):

Gas Exchange ◽

Carica Papaya ◽

Leaf Gas Exchange ◽

Carbon Dioxide Concentration ◽

Field Capacity ◽

Experimental Period ◽

Clay Loam ◽

Clay Loam Soil ◽

Loam Soil ◽

Gas Exchange Characteristics

In this research, was used four papaya (Carica papaya L.) genotypes: three from the 'Solo ( Sunrise Solo TJ, Sunrise Solo 72/12 and Baixinho de Santa Amália) group and one from the 'Formosa' group (Know-You 01). They were grown in plastic pots containing a sandy-clay-loam soil subjected to pH correction and fertilization, under greenhouse conditions. Throughout the experimental period plants were subjected to periodic irrigation to maintain the soil humitidy around field capacity. The experiment was conducted 73 days after sowing. In all genotypes, leaf gas exchange characteristics were determined. The net photosynthetic rate (A, mumol m-2 s-1 ), stomatal conductance (g s mol m-2 s-1), leaf temperature (T I, 0C) and intercellular carbon dioxide concentration (ci, muL L-1) on the 4th, 5th, 6th, 7th, 8th and 9th leaves from the plant apex were determined. No significant differences were observed for A, g s, c i, or Tl either among the leaves sampled from any of the genotypes. A was positively correlated with g s and in the other hand T I and g s were negatively correlated. The results suggest that, for 73 DAP, all the sampled papaya leaves functioned as sources of organs.

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Differential responses between mature and young leaves of sunflower plants to oxidative stress caused by water deficit

Ciência Rural ◽

10.1590/s0103-84782010000600008 ◽

2010 ◽

Vol 40 (6) ◽

pp. 1290-1294 ◽

Cited By ~ 11

Author(s):

Inês Cechin ◽

Natália Corniani ◽

Terezinha de Fátima Fumis ◽

Ana Catarina Cataneo

Keyword(s):

Water Stress ◽

Gas Exchange ◽

Leaf Gas Exchange ◽

Intercellular Co2 Concentration ◽

Leaf Age ◽

Co2 Concentration ◽

Mature Leaves ◽

Young Leaves ◽

Mda Content ◽

Gas Exchange Characteristics

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.

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