Table 2. Model Constants for the Skewed and Gaussian Models of Control (A) and Limited Irrigation (B) with Foliar Application of PSAP in Sugarcane Plants^a.

(A)
		control (95–90% of FC)
		Skewed model			Gaussian model
photosynthetic responses	PSAP (M)	α	β	γ	a	b	c
PN	0	21.60	83.27	17.58	21.97	1.71	3.99
	2	21.97	1634.09	15.78	22.33	1.91	4.14
	4	24.14	104.69	11.92	24.22	1.46	5.05
	6	28.80	14.24	47.96	29.32	0.73	5.67
	10	28.89	34.65	92.81	29.49	0.017	6.27
gs	0	146.38	107.68	5.98	158.13	–1.79	6.43
	2	205.52	156.24	2.71	306.89	–4.09	17.33
	4	259.95	151.97	2.33	199.51	–95.63	25.83
	6	245.28	603.60	2.88	100.48	–109.31	26.79
	10	295.67	722.28	2.12	233.27	–35.47	2.07
E	0	1.98	1.48	18.94	2.03	0.47	4.60
	2	2.04	2.46	14.33	2.07	0.95	4.02
	4	2.27	47.36	8.54	2.27	0.69	4.59
	6	2.90	2.84	10.32	3.04	–0.14	4.55
	10	2.86	7.19	5.74	3.06	–0.89	5.06

(B)
		drought (45–40% of FC)
		Skewed model			Gaussian model
photosynthetic responses	PSAP (M)	α	β	γ	a	b	c
PN	0	13.38	5.38	258.18	14.81	–1.41	6.69
	2	15.77	8.39	42.42	17.13	–0.86	5.84
	4	17.57	17.18	7.81	19.18	–1.32	5.96
	6	20.08	22.94	7.37	21.66	–1.05	5.67
	10	20.32	62.38	5.39	22.78	–2.17	6.35
gs	0	91.27	60.04	43.07	92.95	7.28	4.16
	2	97.25	64.25	59.28	98.23	1.26	3.99
	4	123.37	194.81	9.14	124.71	0.63	4.03
	6	128.98	142.99	17.43	130.95	0.99	4.09
	10	129.27	273.39	8.52	130.61	0.62	4.32
E	0	1.13	0.83	5.76	1.39	–6.78	12.41
	2	1.21	2.58	6.07	1.301	–2.84	10.14
	4	1.22	0.81	41.47	1.24	1.69	5.24
	6	1.45	10.42	7.30	1.49	–0.34	6.45
	10	1.28	30.83	11.15	1.30	0.75	6.30

^aP_N = photosynthesis, gs = stomatal conductance to water vapor, and E = transpiration rate.