Table 3. Pearson correlation coefficients (n = 15) between activity of sucrose-metabolized enzymes and carbohydrate concentrations in leaves or between activity of proline-metabolized enzymes and proline concentrations in leaves of trifoliate orange seedlings.

	AI			NI			SS			SPS			Net activity of sucrose-metabolized enzymes			Proline
	Fructose	Glucose	Sucrose	Fructose	Glucose	Sucrose	Fructose	Glucose	Sucrose	Fructose	Glucose	Sucrose	Fructose	Glucose	Sucrose	P5CR	PSCS	OAT	ProDH
WW	−0.03	0.28	0.09	0.39	0.14	0.40	−0.25	−0.60*	−0.40	0.81**	0.98**	0.91**	0.74**	0.97**	0.86**	0.65**	0.82**	−0.35	−0.50
DS	−0.35	−0.57*	−0.34	0.60*	0.77**	0.61*	−0.84**	−0.97**	−0.88**	0.92**	0.98**	0.95**	0.87**	0.98**	0.90**	0.62*	0.48	−0.41	−0.52*

^*P < 0.05; **P < 0.01. Abbreviation: AI, acid invertase; DS, drought stress; NI, neutral invertase; OAT, ornithine-δ-aminotransferase; P5CR, Δ₁-pyrroline-5-carboxylate reductase; P5CS, Δ_1-pyrroline-5-carboxylate synthetase; ProDH, proline dehydrogenase; SPS, sucrose phosphate synthase; SS, sucrose synthase; WW, well watered.