Leaf Temperature and Internal Water Status of Wheat Grown at Different 1Root Temperatures


By jpeza - Posted on 02 Diciembre 2010

Fecha Publicación: 
1 Ene 1978
Nombre de Revista: 
Datos del paper
Autor Principal: 
M. B. Kirkham
Volumen: 
70
Issue: 
4
Página Inicial: 
657
Página Final: 
662
Abstract: 

Both root temperature and plant water status are important
in controlling plant growth. Yet few studies
report the influence of root temperature on the water
relations of plants. Therefore, to determine the effect
of root temperature on leaf temperature and internal
water status, a cultivar of winter wheat (Trlticum aestirum
L. em Thell. ’Ponca’), considered to be drought
sensitive, was grown for 82 days, under growth room
conditions, at six different root temperatures (15.6, 19.9,
24.7, 28.5, 32.1 and 37.3 C). The air temperature remained
constant at 25 C. Leaf temperature and stomatal
resistance were measured daily starting on day 18. Leaf
water, osmotic, and turgor potentials were determined
every other day starting on day 44. No seeds germinated
at 37.3 C. During the experiment, leaf temperatures were
lower than air temperature by 1.46, 1.16, 1.12, 0.98,
and 0.71 C for the 15.6, 19.9, 24.7, 28.5 and 32.1 C root
temperatures, respectively. Stomatal resistances averaged
21.5, 19.9, 19.8, 22.1, and 27.4 sec/cm for the
15.6, 19.9, 24.7, 28.5, and 32.1 C root temperatures, respectively.
Leaf water, osmotic, and turgor potentials
were highest at the 24.7 C root temperature. Potentials
were lowest at the highest root temperature (32.1 C).
The experiment was repeated using a wheat cultivar
considered to be drought resistant (’KanKing’).
KanKing seeds germinated at 37.3 C. For KanKing, leaf
temperatures were cooler than air temperature by 1.75,
1.51, 1.36, 1.32, and 1.02 C for the 15.6, 19.9, 24.7,
28.5, and 32.1 C root temperatures, respectively. Stomatal
resistances averaged 44.6, 41.9, 33.5, 37.0, and 37.4 sec/cm
for the 15.6, 19.9, 24.7, 28.5, and 32.1 C root temperatures,
respectively. Potentials were not determined for Kan-
King. The drought sensitive cultivar grew taller than the
drought resistant cultivar. But the heights of both cultivars,
decreased in the following order with root temperature:
24.7, 28.5, 19.9, 15.6, and 32.1 C. The results
showed that the drought resistant cultivar maintained a
larger difference between leaf and air temperature at
the different root temperatures than did the drought
sensitive cultivar. This suggested that leaf temperature
measurements could be used to screen plants for drought
resistance.

Keywords: 
Water potential
Osmotic potential
Turgor potential
Stomatal resistance
Triticum aestivum L. em Thell.R. M. Ahring
Coautores: 

R. M. Ahring

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