Table 2.

Basal (nonstressed) alterations to plant physiology of evergreen oak (Quercus ilex L.) at week 2 after paclobutrazol (PBZ) application.^{^z^y}

Parameter	Control	2 mL (0.06 fl oz) PBZ foliar spray	4 mL (0.12 fl oz) PBZ foliar spray	5 mL (0.15 fl oz) PBZ root drench	10 mL (0.3 fl oz) PBZ root drench	Percent change by PBZ
Membrane integrity	2.73	1.99*	1.80*	2.33*	2.17*	−14.6–34.1
PI	6.67	7.54*	7.23*	6.88^ns	7.38*	+3.0–11.5
Pn	4.33	4.75^ns	5.27*	4.81^ns	4.49^ns	+3.6–17.8
Carotenoids (lutein: β-carotene:neoxanthin:α-carotene)	4.97 (60:16:21:3)	6.52* (62:14:22:2)	7.23* (59:16:21:4)	7.35* (60:18:20:2)	7.08* (57:19:21:3)	+19.9–24.9
Xanthophylls (zeaxanthin:antheraxanthin:violaxanthin)	3.43 (44:17:39)	4.08* (40:17:43)	4.09* (44:19:37)	4.53* (44:17:39)	4.04* (41:19:40)	+13.2–16.3
Total carotenoids (x + c)	8.41	10.60*	11.32*	11.88*	11.13*	+18.6–22.4
Proline	137.4	165.7*	166.7*	172.1*	159.3^ns	+13.7–20.2
SOD	228.5	266.7*	248.9*	271.5*	302.8*	+8.2–24.5
Catalase	901.5	1243.4*	1338.9*	1435.6*	1269.0*	+27.5–37.2
Leaf necrosis	0.0	0.0^ns	0.0^ns	0.0^ns	0.0^ns	0
Chlorophyll a/b	3.34	3.45^ns	3.32^ns	3.23^ns	3.15^ns	−5.6-+3.2
Total chlorophylls	94.5	117.8*	123.1*	132.5*	126.5*	+19.8–28.6

↵^zTrees were placed under glasshouse conditions (22°C ± 2°C [71.6°F ± 35.6°F], 16 hr light/8 hr dark photoperiod and minimum 250 μmol/m⁻²/s⁻¹ photosynthetically active radiation at the tree crown).
↵^yMembrane integrity, PI, chlorophylls, carotenoids, xanthophylls, leaf proline, SOD, catalase, and leaf necrosis values mean of ten trees. Membrane integrity (percent electrolyte leakage), leaf chlorophylls, carotenoids, and xanthophylls content μg/g fresh leaf weight), leaf proline μg/g dry leaf weight), SOD (units g fresh leaf weight), catalase μmol/min⁻¹ g fresh leaf weight).
*Significantly different from controls according to least significant difference at P < 0.05; ^ns = not significantly different from control value.
PI = photosynthetic efficiency; Pn = light-induced CO2 fixation; SOD = superoxide dismutase.