. 2019 Jul 3;10:815. doi: 10.3389/fpls.2019.00815

TABLE 2.

Effects of the drought/re-watering treatment on leaf proline content (μmol g^–1), soluble sugar (mg g^–1), and starch content (mg g^–1) in C. virgata (annual C₄), H. altissima (perennial C₄), and L. chinensis (perennial C₃).

Species			Drought				Re-watering	Significance (D)			Significance (R)
			Day 1	Day 3	Day 5	Day 7	Day 14	D	N	D × N	R	N	R × N
Chloris virgata	Proline	N0	0.01 ± 0.01	0.11 ± 0.01	0.16 ± 0.01	0.32 ± 0.01	0.20 ± 0.01	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗
	(μmol g^–1)	N10	0.16 ± 0.01	0.24 ± 0.03	1.63 ± 0.14	10.52 ± 0.80	3.45 ± 0.78
	Soluble sugar	N0	11.17 ± 0.65	15.22 ± 0.36	18.90 ± 0.50	23.11 ± 0.63	13.73 ± 0.61	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗	^∗∗∗	ns
	(mg g^–1)	N10	14.03 ± 0.38	24.33 ± 0.88	29.34 ± 0.37	28.18 ± 0.82	16.78 ± 0.71
	Starch	N0	41.06 ± 2.82	19.04 ± 1.15	10.36 ± 0.77	10.51 ± 0.27	27.94 ± 1.09	^∗∗∗	^∗∗∗	ns	^∗∗∗	^∗∗∗	ns
	(mg g^–1)	N10	33.68 ± 0.33	14.50 ± 0.57	7.32 ± 0.26	4.77 ± 0.33	14.80 ± 0.44
Hemarthria altissima	Proline	N0	0.04 ± 0.01	0.07 ± 0.01	0.11 ± 0.01	0.15 ± 0.01	0.09 ± 0.01	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	ns
	(μmol g^–1)	N10	0.17 ± 0.01	0.21 ± 0.02	0.31 ± 0.02	0.46 ± 0.02	0.23 ± 0.01
	Soluble sugar	N0	32.87 ± 3.36	38.36 ± 0.65	47.06 ± 1.45	57.70 ± 2.05	32.90 ± 2.12	^∗∗∗	^∗∗∗	^∗∗	ns	^∗∗∗	ns
	(mg g^–1)	N10	45.38 ± 6.55	64.10 ± 1.62	72.57 ± 3.11	90.81 ± 3.86	49.15 ± 1.78
	Starch	N0	67.85 ± 0.55	47.03 ± 3.85	25.86 ± 4.56	15.99 ± 1.65	58.69 ± 4.60	^∗∗∗	^∗∗∗	^∗∗∗	ns	^∗∗∗	^*
	(mg g^–1)	N10	44.85 ± 1.94	43.88 ± 1.59	16.76 ± 0.86	18.05 ± 0.96	47.74 ± 3.84
Leymus chinensis	Proline	N0	0.11 ± 0.01	0.12 ± 0.01	0.15 ± 0.01	0.17 ± 0.02	0.16 ± 0.01	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗
	(μmol g^–1)	N10	0.32 ± 0.014	1.24 ± 0.05	4.46 ± 0.14	7.29 ± 0.09	1.91 ± 0.03
	Soluble sugar	N0	70.99 ± 1.31	53.71 ± 3.41	48.97 ± 2.04	40.65 ± 3.41	55.05 ± 4.04	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗∗	^∗∗
	(mg g^–1)	N10	104.26 ± 3.55	63.59 ± 3.09	45.54 ± 1.97	42.90 ± 1.92	72.92 ± 2.91
	Starch	N0	26.47 ± 0.17	22.70 ± 1.30	17.70 ± 1.10	18.71 ± 1.24	25.60 ± 2.07	^∗∗∗	^∗∗	^∗∗∗	^∗∗∗	^∗∗	^∗∗
	(mg g^–1)	N10	37.71 ± 2.50	14.53 ± 0.87	14.70 ± 0.96	15.10 ± 1.23	24.30 ± 1.14

Results of two-way analysis of variance on the effects of drought (D), N addition (N) and their interactions (D × N), as well as re-watering (R), N and their interactions (R × N) on the content of proline, soluble sugar and starch are provided. Levels of significance are indicated as: ns – not significant, ^*P < 0.05, ^∗∗P < 0.01, and ^∗∗∗P < 0.001. Data are reported as the arithmetic mean ± 1 standard error (n = 6).