V. NEW APPROACH TO WATER RELATIONS OF DESERT PLANTS
235
TABLE I I
A. EXAMPLE FOR D I F F E R E N T φ8 VALUES ( M E A S U R E D IN ATM) IN T H E SAME
PLANT D E P E N D I N G ON A G E
Conifer needles"
Species
1-year-old needles
2-year-old needles
Pinus flexilis
Pinus aristata
Abies concolor
-17.7
-15.0
-19.0
- 1 9 . 6
- 2 1 . 7
- 2 2 . 1
B. EXAMPLE FOR D I F F E R E N T ψ8 VALUES ( M E A S U R E D IN ATM) IN THE SAME
P L A N T D E P E N D I N G ON T I S S U E S OR ORGANS
1. Meristematic tissue and stem water storage tissues in Cactaceae
6
Species
Stem water storApical meristem
age tissue
Carnegiea gigantea
Ferocactus wislizenii
-10.0
■ 6.9
- 5 . 6 to
- 4 . 2 to
- 6 . 4
- 5 . 3
2. In herbaceous winter annuals from Arizona
0
Species
Stem
Leaves
Sphaerostigma
chamaenerioides
Calycoseris wrightii
Streptanthus
arizonicus
Eulobus californicus
Nemoseris
neo-mexicana
-11.3
-11.8
-16.9
- 8.7
-15.0
- 1 1 . 5
- 1 1 . 6
- 1 4 . 7
- 1 0 . 7
- 1 4 . 1
3. In plants of the western part of the U.S.A.
d
Allium
cernuum
Mentzelia multiflora
Iris
missouriensis
inflorescences
leaves
bulbs
roots
leaves
tap root
leaves
rhizome
- 1 1 . 4
- 7 . 8
- 8.4
- 6.7
- 1 0 . 9
- 4 . 7
- 1 1 . 4
- 1 0 . 5
4. Organ section: Gradients of ψ β in a leaf of Yucca glauca
e
leaf tip
middle part
leaf base
- 1 4 . 9
- 1 4 . 2
- 1 2 . 6
a From Walter (1931, p . 44, Table 35).
b From Walter (1931, p p . 104-105).
c From Harris and Lawrence (1916, pp. 40, 38, 41, 39, and 34).
d From Walter (1931, p . 41, Table 26).
e From Walter (1931, p . 42, Table 32).