Claim · model-written summary
A rapid reduction of relative humidity to 60% induced a transient decrease in water potential (Ψ) of approximately 4.5 × 10^5 Pa in sunflower.
- Taxon
- sunflower
Helianthus annuuse1 - Treatment
- rapid reduction of relative humidity from 100% to 60 or 40%e7
- Outcome
- Ψe7
- Direction
- decreasese7
- Value
- approximately 4.5e7
Not reportedComparator
Verbatim
e1“using hydroponic sunflower plants”
e7“Abrupt increases in evaporative demand, obtained by rapid reduction of relative humidity from 100% to 60 or 40%, induced transient decreases in Ψ of approximately 4.5 and 2.5 × 105 Pa, respectively, which were accompanied by simultaneous large increases in stomatal resistance”
Title
C. R. BLACK Journal of Experimental Botany 1979. doi:10.1093/jxb/30.2.245
Other claims from this paper (12)
- Intervention effect Cooling the root system to 10 °C or below decreased leaf water potential by up to 7 × 10^5 Pa in hydroponic sunflower.
- Intervention effect Leaf water potential completely recovered after root cooling to 10 °C or below once freezing was avoided.
- Intervention effect Cooling stem or petiolar segments did not affect leaf water status unless freezing occurred.
- Intervention effect Freezing during stem or petiolar cooling caused severe irreversible water stress above the cooled zone.
- Intervention effect Leaves below the cooled zone were unaffected by stem or petiolar cooling.
- Intervention effect A rapid reduction of relative humidity to 40% induced a transient decrease in water potential (Ψ) of 2.5 × 10^5 Pa in sunflower.
- Intervention effect The rapid humidity reduction was accompanied by large simultaneous increases in stomatal resistance in sunflower.
- Intervention effect No simultaneous transient effects were observed in the stem xylem during the rapid humidity reduction.
- Observation Petiolar resistance was low in sunflower petioles, about 0.04 Pa s cm−4.
- Observation Immature and senescent sunflower petioles had petiolar resistance up to 10 times larger than other petioles.
- Mechanism The petiolar resistance trend is attributed to the developmental stage and condition of the xylem.
- Mechanism The factor causing the transient foliar stress is located within the lamina, not in the stem xylem.