Table 2.

M. alba growth parameters estimated using equations under different water stress levels.

Measurement	Treatment	X0	a	GR50	DTlog	DTs
Plant height	T0	14.10 ± 0.51ab	91.03 ± 6.70	5.30 ± 0.21b	17.26 ± 1.60	5.47 ± 0.53
	T1	15.95 ± 0.60a	115.25 ± 18.87	5.89 ± 0.31b	19.37 ± 2.27	6.60 ± 0.32
	T2	12.81 ± 0.36b	91.37 ± 8.06	7.01 ± 0.24a	13.07 ± 1.29	6.27 ± 0.50
	T3	13.19 ± 0.29b	86.54 ± 4.40	6.39 ± 0.23ab	13.60 ± 1.00	6.39 ± 0.22
Significant difference			ns		ns	ns
Leaf length	T0	4.33 ± 0.02b	9.86 ± 0.70	2.04 ± 0.29	4.97 ± 0.43	1.85 ± 0.20
	T1	4.87 ± 0.16ab	12.57 ± 1.40	1.88 ± 0.11	6.83 ± 1.07	1.46 ± 0.38
	T2	4.44 ± 0.17b	10.18 ± 0.06	2.09 ± 0.06	4.88 ± 0.13	2.00 ± 0.11
	T3	5.16 ± 0.08a	13.14 ± 1.40	2.51 ± 0.05	5.22 ± 0.45	2.55 ± 0.30
Significant difference			ns	ns	ns	ns
Leaf width	T0	4.40 ± 0.05ab	9.28 ± 0.31	2.22 ± 0.08	4.18 ± 0.06	2.31 ± 0.04a
	T1	4.34 ± 0.25ab	7.45 ± 0.22	1.39 ± 0.15	5.49 ± 0.70	1.59 ± 0.15b
	T2	3.74 ± 0.07b	7.92 ± 0.45	1.63 ± 0.15	4.89 ± 0.23	1.30 ± 0.12b
	T3	4.84 ± 0.35a	8.54 ± 0.97	1.70 ± 0.38	5.33 ± 0.82	2.18 ± 0.06a
Significant difference			ns	ns	ns

Note: The means ± SE (n = 3) in the table indicate significant differences in M. alba growth parameters estimated during different water stress phases at p ≤ 0.05, according to one-way ANOVA and Tukey-test. Different lowercase letters in the same column indicate significant differences in the measured factor among the four levels. a is the upper limit of the growth index of the whole growth process; X₀ is the time it takes to reach 50% of the maximum increase in the logarithmic growth period (days); GR₅₀ is the growth rate in the half of the logarithmic phase; DT_log is the duration of the logarithmic phase; and DT_s is the time from observation to logarithmic growth. ns is no significant differences. T0 is the control group, T1 is the mild drought, T2 is the moderate drought, T3 is the severe drought.