Effects of microscopic testa color and morphologyon the water uptake ability and drought tolerance of germination-stage rapeseed (Brassica napus L.)

Figures & data

Table 1. Sources and characteristics of rapeseed (Brassica napus L.) germplasm accessions used in the present study

Code	Line	Origin	Name	Type	Seed color	Papilla type
1	Bn07005	YHR	Huang C	genetic material	red	LBP
3	Bn07009	YHR	Shanyou No.10	bred variety	red	MBP
4	Bn07010	YHR	Shanyou No.9	bred variety	black	LSP
5	Bn07011	MYR	Huayouza No.7	bred variety	red	LSP
6	Bn07013	MYR	Huahuang No.1	bred variety	yellow	LBP
7	Bn07014	LYR	Huyou No.15	bred variety	red	LBP
10	Bn07019	UYR	Yuhuang No.1	bred variety	yellow	MSP
12	Bn07021	LYR	Huawanyou No.2	bred variety	red	MBP
13	Bn07022	MYR	Huayou 2008	bred variety	black	LBP
14	Bn07023	MYR	Zhongshuang No.11	bred variety	black	LBP
16	Bn08010	MYR	Zhongshuang No.9	bred variety	black	LBP
17	Bn08011	LYR	Huyou No.18	bred variety	black	MBP
18	Bn08012	LYR	Ningza No.11	bred variety	red	LBP
19	Bn08013	MYR	Fengyou701	bred variety	black	LSP
20	Bn08014	MYR	Xiangzayou No.6	bred variety	black	LSP
21	Bn08015	LYR	Wanyou No.17	bred variety	black	MBP
22	Bn08016	MYR	H9954	genetic material	black	MSP
24	Bn08035	LYR	Zheyou 50	bred variety	black	MSP
25	Bn08036	LYR	Huaiza No.3	bred variety	black	MSP
27	Bn08037	YHR	Yuyou No.5	bred variety	black	LBP
28	Bn08038	YHR	Qinyou No.9	bred variety	red	LBP
32	Bn08043	UYR	Youyan No.10	bred variety	yellow	MSP
33	Bn08044	MYR	Zhongyou012	bred variety	black	LSP
34	Bn08045	UYR	G2153	genetic material	black	LSP
36	Bn08047	MYR	Zhongyouza No.2	bred variety	black	LSP
37	Bn08048	YHR	Qinyan 211	bred variety	black	MSP
39	Bn08110	MYR	Zhongyouza No.8	bred variety	red	MSP
40	Bn08112	MYR	Xiwang 98	bred variety	red	LSP
42	Bn08113	MYR	Zhongyouza No.7	bred variety	black	LBP
43	Bn08114	MYR	Huayouza No.10	bred variety	red	MBP
44	Bn08115	YHR	Qinyou No.6	bred variety	red	LSP
45	Bn08116	MYR	Huayouza No.9	bred variety	black	MSP
47	Bn08119	MYR	Zhongyouza No.11	bred variety	black	MSP
48	Bn08121	MYR	H4270	genetic material	black	MSP
49	Bn08132	LYR	Hongyou No.3	bred variety	black	MSP

UYR: upper Yangzi River; MYR: middle Yangzi River; LYR: lower Yangzi River; YHR: Yellow and Huai River; MBP: more and bigger papilla; LBP: less and bigger papilla; MSP: more and smaller papilla; LSP: less and smaller papilla.

Figure 1. Microscopic color and morphology of testa from 35 rapeseed (Brassica napus L.) accessions from China

Table 2. Micromorphological testa traits of 35 rapeseed (Brassica napus L.) germplasm accessions from China

Index	Min	Max	Mean	STD	CV (%)	Index	Min	Max	Mean	STD	CV (%)
HHSB	75.51	171.22	93.71	21.97	23.44	Dr	182.66	192.09	188.50	1.98	1.05
SHSB	77.87	174.99	101.19	22.99	22.72	Dg	38.19	173.58	77.56	29.43	37.94
BHSB	0.21	0.99	0.89	0.17	19.19	Db	2.35	148.66	18.43	28.17	152.85
RRGB	149.60	205.20	190.39	10.21	5.36	IOD	110,462,000.00	237,129,000.00	132,056,857.1	25,570,052.00	19.36
GRGB	33.40	328.40	82.24	52.73	64.12	No.P	193.00	710.00	490.31	119.65	24.40
BRGB	1.40	151.20	21.51	31.47	146.30	APA	6.60	30.90	15.49	5.28	34.09
L*	33.60	72.60	49.19	7.47	15.19	PAR	10.30	38.50	19.04	7.13	37.45
a*	2.60	56.60	43.48	13.15	30.24	DrP	149.95	210.79	195.46	9.55	4.89
b*	14.60	59.00	52.44	9.34	17.81	DrTP	36230.64	141,568.10	95,737.96	23,271.76	24.31
C	0.25	0.45	0.31	0.04	12.90	DgP	32.30	175.33	102.17	35.53	34.78
M	0.31	0.97	0.80	0.15	18.75	DgTP	9721.52	83,089.91	49,522.07	18,711.41	37.78
Y	0.41	1.00	0.94	0.13	13.83	DbP	1.05	150.29	35.17	34.25	97.38
K	0.00	0.16	0.02	0.03	140.00	DbTP	202.06	51,784.09	16,235.34	13,095.38	80.66

*P < 0.05, ** p < 0.01) H_HSB, hue of testa; B_HSB, brightness of testa; S_HSB, S of testa; B_RGB, B value of RGB; G_RGB, G value of RGB; L*, lightness; a*, from magenta to green; b*, from yellow to blue; M, magenta; Y, yellow; D_b, blue channel gray value of testa; IOD, integrated optical density; D_rP, red channel gray value of papilla; D_gP, green channel gray value of papilla; D_bP, blue channel gray value of papilla; D_g, green channel gray value of; D_b, blue channel gray value of testa; No.P, number of papillae; APA, average papillae area; PAR, papillae area ratio.

Table 3. Effect of imbibition duration on the water uptake and electrical conductivity of seed from rapeseed (Brassica napus L.) germplasm accessions from China

	Increase in fresh weight (%)								Electric conductivity (μSg^−1cm^−1)
Accession	1 h	2 h		3 h	4h	5 h		24 h	1 h	2 h	3 h	4 h	5 h	24 h
1	21.0	49.2		54.2	67.4	84.3		89.5	37.2	98.6	121.0	140.1	170.4	243
3	16.8	52.7		54.7	58.6	79.1		79.2	29.7	56.2	61.7	86.6	110.0	160
4	21.5	47.2		51.6	55.8	73.2		79.5	18.8	37.4	46.1	58.0	75.3	119
5	18.8	46.0		47.3	57.0	73.6		81.9	14.7	32.3	41.2	51.7	65.7	111
6	46.0	75.7		76.1	77.5	78.1		85.2	136.8	158.3	176.6	196.2	271.0	322
7	31.8	56.3		57.5	61.7	79.0		83.6	48.6	99.7	101.6	133.0	155.1	235
10	47.8	56.5		57.2	58.3	75.8		81.8	115.7	126.2	139.1	145.4	150.6	162
12	28.8	53.7		58.7	64.3	84.2		96.6	14.2	36.5	45.6	60.9	79.8	132
13	30.9	51.2		55.8	68.2	88.5		99.8	41.7	77.4	81.5	85.1	99.3	146
14	29.9	57.0		59.4	64.8	80.5		86.4	24.4	40.0	52.7	68.5	94.7	151
16	34.6	57.8		59.4	64.7	86.3		97.5	25.6	46.1	47.5	59.7	74.5	128
17	38.9	53.9		76.5	77.0	99.7		109.2	44.8	67.5	80.9	101.3	124.4	221
18	37.5	53.9		56.7	73.2	92.9		101.7	42.5	59.0	71.9	86.5	131.2	184
19	33.6	50.1		58.3	61.0	81.9		88.5	43.2	52	63.2	75.9	108.7	161
20	45.8	62.7		66.9	74.3	94.1		104.9	54.6	89.1	95.3	110.2	137.9	198
21	35.2	52.1		56.1	67.3	84.9		93.5	25.1	38.3	53.0	70.4	109.5	162
22	40.2	59.5		63.7	77.0	97.1		107.7	38.4	52.8	70.8	98.9	122.5	182
24	15.5	53.8		58.0	72.2	89.4		105.9	24.5	35.5	45.4	58.0	71.3	120
25	13.8	27.2		32.3	41.4	57.7		65.7	29.2	40.8	54.7	70.5	84.1	130
27	35.2	51.8		55.6	56.2	73.5		80.3	27.9	32.9	47.5	64.1	80.1	120
28	37.6	49.9		54.3	54.6	74.8		81.2	63.5	78.1	83.4	99.3	108.6	154
32	59.7	76.7		78.1	79.8	96.5		102.4	152.1	186.3	193.6	201.7	228.2	237
33	54.7	65.6		67.7	69.6	84.9		90.3	54.5	65.2	88.2	100.6	130.5	197
34	36.6	50.3		50.6	50.8	67.6		74.6	67.7	71.5	83.5	85.2	115.7	172
36	30.6	45.8		47.7	58.5	74.6		81.6	32.1	49.8	54.1	65.1	77.3	114
37	30.6	39.4		42.8	58.0	74.0		79.6	18.1	36.3	37.5	44.7	54.3	88
39	37.8	62.8		64.1	69.0	88.0		95.7	56.8	76.1	108.2	133.7	157.6	233
40	29.6	41.8		45.0	60.2	78.9		89.5	42.8	43.5	54.6	67.9	81.1	135
42	36.3	51.9		54.6	61.3	81.3		87.1	61.4	105.5	80.0	95.6	112.7	160
43	33.9	49.9		54.7	62.9	87.3		94.6	104.5	108.2	108.7	109.0	124.9	164
44	38.8	52.1		53.8	64.4	84.3		91.6	62.7	73.4	93.5	109.5	125.9	170
45	48.6	63.2		68.7	70.7	86.1		92.5	108.2	109	110.4	123.0	162.5	209
47	48.6	58.2		59.7	65.9	85.5		95.7	81.7	98.5	109.0	124.8	144.5	180
48	45.2	61.7		61.9	62.5	80.1		86.1	55.9	67.4	79.2	100.1	109.7	162
49	48.3	70.7		74.1	82.6	96.5		102.4	57.7	72.3	80.9	98.2	107.1	153
mean	35.4	54.5		58.1	64.8	82.7		90.4	53.1	71.9	81.8	96.6	118.8	169
F value
HHSB	0.25	0.38*		0.28	0.16		−0.04	−0.1	0.34*	0.35*	0.44**	0.45**	0.46**	0.43**
SHSB	−0.42*	−0.53**	−0.48**		−0.38*		−0.14	−0.07	−0.62**	−0.59**	−0.70**	−0.66**	−0.67**	−0.63**
BHSB	0.18	0.34*	0.24		0.13		−0.04	−0.1	0.28	0.32	0.40*	0.43**	0.43**	0.41*
GRGB,	0.09	0.18	0.16		0.13		0.12	0.05	0.48**	0.44**	0.46**	0.40*	0.38*	0.34*
BRGB	0.40*	0.53**	0.48**		0.38*		0.13	0.06	0.63**	0.60**	0.70**	0.67**	0.68**	0.64**
L*	0.17	0.36*	0.36*		0.27		0.09	0	0.39*	0.43**	0.54**	0.54**	0.57**	0.60**
a*	−0.25	−0.40*	−0.34*		−0.24		−0.09	0.01	−0.47**	−0.49**	−0.60**	−0.59**	−0.59**	−0.58**
b*	−0.48**	−0.53**	−0.45**		−0.34*		−0.1	−0.05	−0.65**	−0.59**	−0.67**	−0.62**	−0.62**	−0.53**
M	−0.19	−0.39*	−0.36*		−0.26		−0.1	−0.02	−0.40*	−0.46**	−0.56**	−0.55**	−0.56**	−0.56**
Y	−0.42*	−0.55**	−0.50**		−0.41*		−0.16	−0.11	−0.58**	−0.56**	−0.68**	−0.65**	−0.68**	−0.64**
Db	0.24	0.25	0.17		0.02		−0.19	−0.21	0.36*	0.33*	0.37*	0.37**	0.40*	0.35*
IOD	0.16	0.2	0.15		0.01		−0.19	−0.21	0.29	0.31	0.33*	0.34*	0.38*	0.34*
No.P	0.21	0.16	0.22		0.22		0.33*	0.35*	0.11	013	0.1	0.08	0.09	0.07
DrP	0.18	0.16	0.24		0.34*		0.43**	0.39*	0.06	0.22	0.23	0.23	0.25	0.3
APA	−0.01	0.12	0.21		0.29		0.36*	0.31	0.06	0.29	0.27	0.27	0.32	0.37*
PAR	−0.01	0.12	0.24		0.34*		0.43**	0.39*	0.06	0.07	0.22	0.23	0.25	0.3

*P < 0.05, ** p < 0.01) H_HSB, hue of testa; B_HSB, brightness of testa; S_HSB, S of testa; B_RGB, B value of RGB; G_RGB, G value of RGB; L*, lightness; a*, from magenta to green; b*, from yellow to blue; M, magenta; Y, yellow; D_b, blue channel gray value of testa; IOD, integrated optical density; D_rP, red channel gray value of papilla; D_gP, green channel gray value of papilla; D_bP, blue channel gray value of papilla; D_g, green channel gray value of; D_b, blue channel gray value of testa; No.P, number of papillae; APA, average papillae area; PAR, papillae area ratio.

Figure 2. Effect of testa color and morphology on the water uptake rate of rapeseed accessions from China. (a) Effect of testa color. (b) Effect of testa morphology

Figure 3. Effect of testa color and morphology on the rate of electric conductivity increase for rapeseed accessions from China. (a) Effect of testa color. (b) Effect of testa morphology

Figure 4. (a and d) Relative germination rate. (b and e) Relative seedling height. (c and f) DTI of seedling height

Figure 5. Principal component analysis of relationships among micromorphological testa characteristics. (a) Contribution of testa characteristics to two main principal components. (b) Grouping of accessions based on two main principal components

Table 4. Drought tolerance parameters of 35 rapeseed (Brassica napus L.) germplasm accessions from China

Accession	Germination rate (control)	Germination rate (drought)	Seedling height (control)	Seedling height (drought)	Seedling fresh weight (control)	Seedling fresh weight (drought)	Relative germination rate (%)	Relative Seedling Height (%)	Drought tolerance index
1	85.0	72.0	3.40	1.55	0.039	0.027	84.7	45.6	0.39
3	96.5	92.5	2.60	1.65	0.029	0.021	95.9	63.5	0.61
4	91.5	86.5	3.45	2.65	0.035	0.027	94.5	76.8	0.73
5	92.0	81.0	3.60	2.70	0.042	0.025	88.0	75.0	0.66
6	76.5	65.5	2.55	2.20	0.040	0.037	85.6	86.3	0.74
7	75.5	61.0	3.70	2.15	0.049	0.027	80.8	58.1	0.47
10	91.0	80.5	3.10	1.60	0.040	0.023	88.5	51.6	0.46
12	97.5	94.5	3.35	2.45	0.049	0.022	96.9	73.1	0.71
13	95.5	89.0	2.95	2.60	0.040	0.030	93.2	88.1	0.82
14	94.5	86.0	3.75	3.50	0.040	0.032	91.0	93.3	0.85
16	97.5	83.3	3.40	2.62	0.034	0.022	85.4	77.2	0.66
17	99.0	84.6	3.08	2.31	0.028	0.030	85.4	75.0	0.64
18	99.0	83.7	3.68	2.92	0.044	0.038	84.6	79.3	0.67
19	95.0	82.5	3.73	2.82	0.050	0.032	86.8	75.6	0.66
20	98.0	83.7	3.22	2.72	0.037	0.031	85.4	84.6	0.72
21	98.0	85.0	3.21	2.84	0.035	0.029	86.7	88.5	0.77
22	99.5	83.7	3.14	3.00	0.037	0.034	84.2	95.7	0.81
24	97.0	84.6	4.15	2.79	0.035	0.025	87.2	67.2	0.59
25	89.5	82.5	3.92	2.44	0.049	0.025	92.1	62.1	0.57
27	98.5	83.3	3.39	2.41	0.039	0.030	84.6	70.9	0.6
28	98.5	84.6	4.83	2.45	0.040	0.022	85.9	50.6	0.43
32	95.5	79.1	2.82	1.82	0.051	0.035	82.8	64.5	0.53
33	99.0	82.5	3.00	2.16	0.037	0.028	83.3	72.0	0.60
34	98.5	83.3	2.81	2.19	0.042	0.030	84.6	78.1	0.66
36	98.5	85.0	3.45	2.32	0.042	0.030	86.3	67.3	0.58
37	99.0	84.6	3.56	2.10	0.040	0.028	85.4	58.9	0.50
39	97.5	81.2	4.16	3.09	0.042	0.032	83.3	74.2	0.62
40	100.0	84.2	3.09	2.74	0.039	0.0033	84.2	88.7	0.75
42	97.0	83.7	3.68	2.34	0.041	0.027	86.3	63.7	0.55
43	98.5	83.3	3.54	2.37	0.035	0.021	84.6	67.0	0.57
44	94.0	79.9	4.05	3.15	0.034	0.026	85.0	77.7	0.66
45	99.5	85.0	3.16	2.59	0.035	0.027	84.5	85.7	0.72
47	98.0	83.7	3.03	2.27	0.051	0.032	85.4	75.0	0.64
48	96.5	82.0	2.60	1.4	0.035	0.016	85.0	70.0	0.59
49	97.0	83.7	3.18	2.70	0.051	0.038	86.3	84.8	0.73
	95.2	82.6	3.38	2.44	0.040	0.028	86.7	73.3	0.64
BRGB	−0.37*	−0.44**	−0.34*	−0.29	0.13	0.29	−0.23	−0.03	−0.09
HHSB	−0.47**	−0.36*	−0.25	−0.39*	0.07	0.05	0.06	−0.26	−0.23
SHSB	0.36*	0.43*	0.34*	0.3	−0.15	−0.29	0.22	0.04	0.1
BHSB	−0.46**	−0.31	−0.22	−0.39*	0.04	0.01	0.11	−0.3	−0.26
L*	−0.41*	−0.39*	−0.25	−0.4*	−0.04	0.05	−0.1	−0.24	−0.26
B*	0.3	0.39*	0.32	0.17	−0.24	−0.37*	0.24	−0.08	−0.01
M	0.38*	0.33	0.25	0.40*	0.01	−0.06	0.03	0.25	0.25
Y	0.35*	0.44**	0.38*	0.25	−0.11	−0.33*	0.24	−0.05	0.01
Dg	−0.57**	−0.43**	−0.07	−0.3	0.01	−0.07	0.06	−0.29	−0.25
Db	−0.49**	−0.40*	−0.20	−0.33*	0.03	−0.02	0.02	−0.22	−0.21
DgP	−0.43*	−0.31	0.02	−0.09	0.03	−0.07	0.08	−0.13	−0.1
DbTP	−0.32	−0.31	0.01	−0.34*	−0.02	−0.02	−0.09	−0.40*	−0.39*

(*P < 0.05, ** P < 0.01) EC:electric conductivity, WI:weight increase; H_HSB, hue of testa; B_HSB, brightness of testa; S_HSB, S of testa, B_RGB, B value of RGB; G_RGB,G value of RGB; L*, lightness; a, from magenta to green; b*, from yellow to blue; M, magenta; Y, yellow IOD, integrated optical density; D_rP, red channel gray value of papilla; D_gP green channel gray value of papilla; D_bTP, blue channel gray value of total papilla; D_g, green channel gray value of testa; D_b, blue channel gray value of testa.

Table 5. Eigenvalues and contribution rate of principal components

Parameters	PC1	PC2	PC3
HHSB	0.326	0.166	−0.101
BHSB	0.319	0.155	−0.060
SHSB	−0.336	0.274	0.008
BRGB	0.332	−0.288	0.021
L	0.320	−0.061	0.215
b	−0.286	0.339	0.159
M	−0.331	0.121	−0.155
Y	−0.329	0.230	0.019
Dg	0.201	0.415	−0.073
Db	0.033	0.112	0.927
DgP	0.250	0.475	0.005
DbTP	0.251	0.441	−0.161
Eigen values	7.426	1.887	1.058
Contribution rate (%)	61.884	15.723	8.820
Cumulative contribution rate (%)	61.884	77.608	86.428

H_HSB, Hue of testa; B_HSB, Brightness of testa; S_HSB, S of testa, B_RGB, B value of RGB; L,lightness; a, from magenta to green; b, from yellow to blue; M, magenta;Y,yellow;D_gP green channel gray value of papilla; D_bTP, blue channel gray value of total papilla; D_g, green channel gray value of; D_b, blue channel gray value of testa.