Table 4.

The effects of 21 days of drought on chlorophyll fluorescence (PI), photosynthetic CO2 fixation (Pn), leaf chlorophyll content, and necrosis of containerized evergreen oak (Quercus ilex L.).^{^z^y}

	PI	Pn	Chlorophyll content	Leaf necrosis	Membrane integrity	Survival (%)
Control	1.70	1.59	50.6	3.8	25.4	40
2 mL (0.06 fl oz) PBZ foliar spray	2.27^ns	2.83*	95.8*	2.7^ns	18.6^ns	80*
4 mL (0.12 fl oz) PBZ foliar spray	2.57^ns	1.98^ns	61.0^ns	2.8^ns	17.4^ns	60^ns
5 mL (0.15 fl oz) PBZ root drench	2.42^ns	2.07^ns	68.7^ns	3.0^ns	16.0^ns	80*
10 mL (0.3 fl oz) PBZ root drench	3.34*	1.78^ns	84.3*	2.4^ns	12.3*	60^ns

↵^zMeasurements were made immediately at the cessation of the drought treatment when trees 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).
↵^yTwo milliliters PBZ foliar spray and 5 mL (0.15 fl oz) PBZ root drench-treated plants: PI and leaf chlorophyll content, values mean of eight trees, five leaves per tree. Pn and electrolyte leakage values mean of eight trees, two leaves per tree. Leaf necrosis values mean of ten trees. Four milliliters PBZ foliar spray and 10 mL (0.3 fl oz) PBZ root drench-treated plants: PI and leaf chlorophyll content, values mean of six trees, five leaves per tree. Pn and electrolyte leakage values mean of six trees, two leaves per tree. Leaf necrosis values mean of ten trees. Controls: PI and leaf chlorophyll content, values mean of four trees, five leaves per tree. Pn and electrolyte leakage values mean of four trees, two leaves per tree.
*Significantly different from controls according to least significant difference at P < 0.05; ^ns = not significantly different from control value.
PBZ = paclobutrazol.