. 2022 Dec 12;22:578. doi: 10.1186/s12870-022-03978-y

Table 1.

Effect of SL on the photosynthetic parameters of P. purpureum leaves under drought stress

Treatment		Net photosynthetic rate	Stomatal conductance	Transpiration rate	Intercellular CO₂ concentration	Water use efficiency
Treatment		μmol·(m²·s)⁻¹	μmol·(m²·s)^− 1	mmol·(m²·s)^− 1	μmol∙mol^− 1	mmol·mol^− 1
24 h	N	19.94 ± 0.24^a	174.20 ± 1.80^a	4.46 ± 0.02^a	154.00 ± 2.28^b	4.47 ± 0.03^a
	D	12.14 ± 0.51^c	98.00 ± 2.55^b	3.23 ± 0.07^c	148.80 ± 8.48^b	3.76 ± 0.16^b
	T1	16.54 ± 0.90^b	178.60 ± 8.27^a	3.81 ± 0.11^b	189.60 ± 10.12^a	4.35 ± 0.21^a
	T2	17.06 ± 1.73^ab	184.20 ± 23.50^a	4.43 ± 0.34^a	184.60 ± 3.94^a	3.81 ± 0.11^b
	T3	15.94 ± 1.01^b	172.80 ± 11.68^a	4.54 ± 0.15^a	189.60 ± 2.73^a	3.50 ± 0.15^bc
	T4	12.42 ± 1.08^c	123.80 ± 10.88^b	4.00 ± 0.17^ab	183.20 ± 5.68^a	3.08 ± 0.15^c
48 h	N	18.80 ± 0.33^a	137.40 ± 4.20^b	4.21 ± 0.06^a	133.20 ± 6.35^c	4.47 ± 0.14^a
	D	11.14 ± 0.56^bc	103.40 ± 6.71^c	2.66 ± 0.09^cd	185.20 ± 15.86^b	4.21 ± 0.25^ab
	T1	12.48 ± 1.00^b	165.60 ± 16.34^a	3.91 ± 0.20^ab	225.80 ± 8.65^a	3.19 ± 0.19^c
	T2	12.84 ± 0.82^b	133.60 ± 9.50^b	3.56 ± 0.17^b	194.00 ± 7.12^b	3.61 ± 0.18^bc
	T3	11.94 ± 0.30^b	112.00 ± 4.44^bc	2.85 ± 0.07^c	181.40 ± 5.07^b	4.19 ± 0.11^ab
	T4	9.38 ± 0.97^c	94.00 ± 6.56^c	2.38 ± 0.12^d	201.20 ± 10.20^ab	3.90 ± 0.26^ab
120 h	N	19.56 ± 0.54^a	168.60 ± 16.50^a	5.04 ± 0.31^a	138.60 ± 7.26^b	4.24 ± 0.20^bc
	D	7.66 ± 1.15^d	59.20 ± 8.11^d	1.78 ± 0.19^c	163.60 ± 8.43^a	3.91 ± 0.16^c
	T1	14.98 ± 0.50^b	128.20 ± 5.28^b	3.16 ± 0.15^b	159.20 ± 1.53^a	4.76 ± 0.14^ab
	T2	13.16 ± 0.75^b	99.00 ± 8.45^c	2.76 ± 0.10^b	137.40 ± 6.55^b	4.75 ± 0.16^ab
	T3	10.42 ± 0.93^c	76.00 ± 8.23^cd	2.11 ± 0.18^c	138.60 ± 11.05^b	4.96 ± 0.25^a
	T4	7.50 ± 1.02^d	53.00 ± 5.84^d	1.65 ± 0.15^c	148.20 ± 11.36^ab	4.46 ± 0.26^abc

Different lowercase letters in the same column indicate significant differences (P < 0.05). N: normal watering treatment; D: drought stress treatment only; T1, T2, T3, and T4 represent the different treatment concentrations of SL under drought stress (1, 3, 5, and 7 μmol·L^− 1, respectively)