. 2005 Sep;139(1):546–556. doi: 10.1104/pp.104.058404

Table I.

Xylem functional properties for six chaparral shrub species

Xylem-specific hydraulic conductivity (k_s), xylem density, stem MOR, MOE, xylem pressure potential (P_x) of the dry and wet treatments and at 50% loss of hydraulic conductivity (P₅₀), and the 2004 seasonal low xylem pressure potential (P_min) measured in six co-occurring chaparral species. All values are means ± 1 se, and sample sizes are given in column n. An asterisk indicates significant difference (P < 0.05) between fully saturated wet stems and dry stems dehydrated to approximate minimum water potentials experienced in the field. Letters indicate significant difference between species for a given parameter.

Species Family	n	A. fasciculatum Rosaceae	A. sparsifolium Rosaceae	C. megacarpus Rhamnaceae	C. spinosus Rhamnaceae	M. laurina Anacardiaceae	R. ovata Anacardiaceae
k_s (10⁻³ m² MPa⁻¹ s⁻¹)	6	0.88 ± 0.01^a	1.60 ± 0.12^a	1.54 ± 0.12^a	1.82 ± 0.29^a	6.46 ± 1.36^b	1.95 ± 0.15^a
Xylem density (kg m⁻³)	12	891 ± 65.0^a	684 ± 26.4^b,c	779 ± 34.6^b	659 ± 27.4^c	489 ± 6.2^d	529 ± 21.1^d
MOR (N mm⁻²)
Dry	12	235 ± 7.5^a	175 ± 7.8^b	212 ± 8.3^c,*	152 ± 5.3^d	114 ± 4.7^e	112 ± 6.1^e
Wet	12	237 ± 11.2^a	178 ± 5.2^b	164 ± 8.1^b	132 ± 8.7^c	112 ± 4.2^c	130 ± 10.0^c
MOE (N mm⁻²)
Dry	12	10,794 ± 505^a,c	7,104 ± 498^b	8,617 ± 955^b,c	9,505 ± 369^c,*	5,392 ± 265^d	4,661 ± 349^d
Wet	12	10,804 ± 707^a	7,353 ± 608^b,c	7,722 ± 1,526^b	6,689 ± 417^c	5,450 ± 339^c	5,349 ± 620^c
P_x (MPa)
Dry	12	−8.13 ± 0.39^a,*	−4.45 ± 0.20^b,*	−10.10 ± 0.31^c,*	−10.05 ± 0.62^c,*	−2.53 ± 0.96^d,*	−2.85 ± 0.50^d,*
Wet	3–12	−0.18 ± 0.06^a	−0.14 ± 0.03^a	−0.26 ± 0.05^a,b	−0.16 ± 0.02^a	−0.43 ± 0.09^b	−0.43 ± 0.10^b
P₅₀	6	−8.23 ± 0.19^a	−5.09 ± 0.34^b	−9.30 ± 0.66^c	−5.38 ± 0.46^b	−0.98 ± 0.31^d	−1.23 ± 0.08^d
P_min	6	−6.53 ± 0.15^a	−4.06 ± 0.18^b	−7.99 ± 0.44^c	−5.34 ± 0.31^d	−2.34 ± 0.09^e	−2.65 ± 0.10^e