Differences in morphological and physiological characteristics in the abscission zone of shattering-prone and shattering-resistant genotypes of Elymus sibiricus

doi:10.11686/cyxb2021045

Abstract

Abstract:

This study examined contrasting shattering-prone and shattering-resistant germplasm lines of Elymus sibiricus in order to explore the morphological characteristics of the abscission zone and identify key factors affecting shattering. Samples were collected in batches from the two germplasm lines at intervals from milk stage until the maturity stage of grain development. The two germplasm lines with their contrasting shattering behavior were compared and morphological characteristics of the abscission zone， enzyme activity， dynamic shattering rate and physiological traits were evaluated. In this way， the differences in shattering-related traits between shattering-prone and shattering-resistant germplasm could be identified， as well as differences in the seedstalk and the spikelet stalk abscission zone. It was found that： 1） The abscission zone development of the shattering-prone germplasm was earlier than that of shattering-resistant germplasm， and the distinction was obvious. The development of the seed-stalk abscission zone was earlier and more obvious than the spikelet stalk abscission zone. Observation of the fracture surface of the abscission zone after shedding revealed that there was a ring structure in the abscission zone. 2） The hydrolase activity differed at each grain maturity stage after the milk stage， and the enzyme activity was generally higher in the later stages of seed maturity. The enzyme activity of shattering-prone germplasm was higher than that of shattering-resistant material， and the enzyme activity of the seedstalk was higher than that of the spikelet stalk， indicating that seedstalk shedding was dominant in the shattering process. 3） As the seed ripened， the incidence of shattering gradually increased. At any given development stage， the shattering rate of shattering-prone germplasm was always higher than that of shattering-resistant germplasm， and the shattering rate of shattering-prone germplasm accelerated from the 16th day after the milk stage of grain development. 4） During the process of seed maturation， the shattering rate was extremely significantly （P<0.01） negatively correlated with water content， conductivity and soluble sugar content and significantly （P<0.05） or extremely significantly （P<0.01） positively correlated with enzyme activity， germination rate and starch content. These findings indicate that physiological substances have a regulatory effect on the shattering of E. sibiricus. Based on the above physiological observations， the 16th day after reaching the milk stage of grain development was identified as the optimal harvesting time for E. sibiricus. At this stage of development， E. sibiricus seeds have high germination vigor but the peak period of seed loss from shattering is avoided.

Key words: shattering, abscission zone, physiological index, optimal harvesting time

Rui WU, Wen-hui LIU, Yong-chao ZHANG, Min-jie LIU. Differences in morphological and physiological characteristics in the abscission zone of shattering-prone and shattering-resistant genotypes of Elymus sibiricus[J]. Acta Prataculturae Sinica, 2022, 31(4): 81-92.

Figures/Tables 11

References 29

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资源编号Germplasm number	采集地点Site	生境Habitat	落粒性Seed shattering	类别Status
16-033	青海门源Menyuan，Qinghai	河边、路边Riverside， roadside	低落粒Low shattering	野生种Wild
17-149	青海贵德Guide，Qinghai	干旱草原Arid grassland	高落粒High shattering	野生种Wild

资源编号Germplasm number	采集地点Site	生境Habitat	落粒性Seed shattering	类别Status
16-033	青海门源Menyuan，Qinghai	河边、路边Riverside， roadside	低落粒Low shattering	野生种Wild
17-149	青海贵德Guide，Qinghai	干旱草原Arid grassland	高落粒High shattering	野生种Wild

乳熟后天数 Days after milk stage （d）	多聚半乳糖醛酸酶活性 Polygalacturonase activity （mg·h^-1·g^-1 FW）			纤维素酶活性 Cellulase activity （μg·min^-1·g^-1 FW）
乳熟后天数 Days after milk stage （d）	高落粒High shattering	低落粒Low shattering	t值t value	高落粒High shattering	低落粒Low shattering	t值t value
1	4.20±0.58e	3.45±0.78d	1.347	293.45±58.32e	133.49±20.45e	4.483*
4	7.35±1.10d	3.00±0.36d	6.509**	414.88±14.93d	360.93±8.95d	5.369**
7	11.47±3.61c	6.02±1.00c	2.521	584.42±37.48c	535.87±48.63c	1.370
10	17.21±0.78b	3.09±0.65d	24.045***	617.79±84.05c	572.68±27.52bc	0.883
13	12.65±0.79c	8.27±0.60b	7.649**	838.05±27.56a	664.22±4.11a	10.804***
16	13.67±1.07c	9.11±1.06b	5.265**	540.34±33.21c	605.29±20.97b	-2.864*
19	12.01±1.59c	5.26±1.49c	5.345**	717.95±16.51b	652.08±29.47a	3.377*
22	20.03±0.92a	18.51±0.87a	2.080	734.73±51.99b	528.11±4.18c	6.862*
F	29.814**	96.485**	-	44.682**	153.269**	-

乳熟后天数 Days after milk stage （d）	多聚半乳糖醛酸酶活性 Polygalacturonase activity （mg·h^-1·g^-1 FW）			纤维素酶活性 Cellulase activity （μg·min^-1·g^-1 FW）
乳熟后天数 Days after milk stage （d）	高落粒High shattering	低落粒Low shattering	t值t value	高落粒High shattering	低落粒Low shattering	t值t value
1	4.20±0.58e	3.45±0.78d	1.347	293.45±58.32e	133.49±20.45e	4.483*
4	7.35±1.10d	3.00±0.36d	6.509**	414.88±14.93d	360.93±8.95d	5.369**
7	11.47±3.61c	6.02±1.00c	2.521	584.42±37.48c	535.87±48.63c	1.370
10	17.21±0.78b	3.09±0.65d	24.045***	617.79±84.05c	572.68±27.52bc	0.883
13	12.65±0.79c	8.27±0.60b	7.649**	838.05±27.56a	664.22±4.11a	10.804***
16	13.67±1.07c	9.11±1.06b	5.265**	540.34±33.21c	605.29±20.97b	-2.864*
19	12.01±1.59c	5.26±1.49c	5.345**	717.95±16.51b	652.08±29.47a	3.377*
22	20.03±0.92a	18.51±0.87a	2.080	734.73±51.99b	528.11±4.18c	6.862*
F	29.814**	96.485**	-	44.682**	153.269**	-

乳熟后天数 Days after milk stage （d）	多聚半乳糖醛酸酶活性 Polygalacturonase activity （mg·h^-1·g^-1）			纤维素酶活性 Cellulase activity （μg·min^-1·g^-1）
乳熟后天数 Days after milk stage （d）	种柄Seedstalk	小穗柄Spikelet stalk	t值t value	种柄Seedstalk	小穗柄Spikelet stalk	t值t value
1	3.72±1.04f	3.92±1.07e	-0.223	190.10±45.22g	236.84±30.21e	-1.488
4	5.61±0.81e	4.74±0.07de	1.855	440.97±4.70f	334.84±15.90d	11.091***
7	9.35±1.32d	8.14±2.36c	0.772	572.48±32.31e	547.81±12.54a	1.233
10	11.93±0.96c	8.37±1.19c	4.028*	689.69±28.99d	500.78±70.14ab	4.312*
13	13.71±1.39b	7.21±1.33cd	5.865**	974.56±37.13a	527.71±13.54a	19.587***
16	10.42±0.90cd	12.36±2.13b	-1.449	748.17±31.79c	397.46±8.80c	18.418***
19	9.05±0.57d	8.21±2.67c	0.531	906.60±25.28b	463.43±17.51b	24.955***
22	21.90±0.82a	16.64±1.29a	5.949**	718.02±21.13cd	544.82±42.09a	6.369**
F	90.348**	17.418**	-	206.852**	35.381**	-