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A Study on Pollination Biology of Paeonia suffruticosa subsp. spontanea (Paeoniaceae)
1
LUO Yi-Bo2 PEI Yan-Long1 PAN Kai-Yu1
HONG De-Yuan
1 (Laboratory of Systematic and
Evolutionary Botany,Institute of Botany,the Chinese Academy of
Sciences,Beijing 100093)
2 (Crop Institute, the Chinese
Academy of Agricultural Sciences, Baishiqiao Road, Beijing 100081)
This compilation is the extract in english of the original article published on the web . Follow the link right above for the entire paper in chinese. The most of the paper is in chinese.
Abstract
Field observation on pollination in three populations of Paeonia suffruticosa subsp. spontanea in southern Shanxi Province showed that five species of bees in two families and four species of beetles were engaged in pollination. Examination on bodies of these insects under SEM, and seed set produced by controlled insect-pollination indicated that the bees, especially the species in the genus Andrena were main pollinators and the beetles except those of small size were only fluctuating vectors. Flowers of this taxon are scented and nonectariferous. Flowers attracted bees and beetles mainly by pollen. A study on seed-set in the three populations revealed considerable variation within and among populations. The plants were no apomict and autogamy, but geitonogamy sometimes could produce mature seeds (x=2.86 seeds per carpel). In the population with less flowers (less than 40 flowers), natural seed-set (x=3.88) was close to the seed-set produced by hand cross-pollination (x=3.21), but in the population with more flowers(near 100 flowers) natural seed-set (x=2.48) was lower than that by hand cross-pollination (x=3.21). The seed-set was low for both natural and artificial cross-pollination with only about one forth of ovules developing into seeds.
Key words
Paeoniaceae; Paeonia suffruticosa subsp. spontanea; Flowering; Pollination biology; Breeding system; Bees; Beetles
|
Fig.1 The distribution of Paeonia suffruticosa subsp. spontanea |
Table 1 Species of bees collected in the flowers of Paeonia suffruticosa. subsp. spontanea (April, 1994)
Andrenidae |
Andrena mikado Strand et Yasumatsu female |
A. stellaria Hirashima female and male |
Andrena sp. female |
Halictidae |
Lasioglossum simplicior Cockerell female |
Lasioglossum sp. |
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Fig.2
The distribution of insect visiting frequency every hour in one
day white collum in the Jishan population. |
Table 2 The seed set of different treatments in two populations of Paeonia suffruticosa subsp. spontanea in S. Shanxi
Treatments |
Popula- |
No.
of |
No.
of |
No.
of |
No.
of |
No.
of |
No.
of |
No.
of |
Seed set** (% of ovules foming mature seeds) |
Isolation
|
a*
|
2
|
2
|
10
|
0
|
0
|
0
|
0
|
0
|
Isolation
|
a
|
2
|
3
|
15
|
0
|
0
|
0
|
0
|
0
|
Artificial
|
a
|
3
|
5
|
15
|
20
|
3
|
7
|
1.33
|
12.59
|
Artificial
|
a
|
3
|
4
|
20
|
37
|
2
|
8
|
1.85
|
17.47
|
Artificial
|
a
|
3
|
3
|
15
|
45
|
3
|
14
|
3.00
|
28.32
|
Natural pollination |
a
|
12
|
12
|
60
|
159
|
10
|
41
|
2.65
|
25.02
|
*
a: Yongji population.
b: Jishan population.
* In Yongji population
the number of follicles with seeds and number of seeds per follicle
were low,because the seed-collecting time was a little over.
**
The mean number of ovules per follicle was 10.59,n=320.
Vectors |
No of indiiduals |
No of flowers |
No of flowers with seeds |
No of follides with seeds |
No of seeds |
No of seeds per follicle |
Beetles |
5 |
5 |
0 |
0 |
0 |
0 |
Bees |
2 |
2 |
1 |
5 |
6 |
1.20 |
Natural
|
4 |
4 |
4 |
19 |
35 |
1.84 |
Table 3 Effect of different pollination vectors on seed out-put in the Jishan population
|
Plate 1 1,8. From Yongji population 1.Dorsal and ventral views of Hylovalgus bioculatus, showing a few pollen grains on its body; 8. Bees collecting pollen in withered androecia, showing many pollen grains on the stigmatic surface; 2,3,4,6,7,9. From Jishan population 2. Ventral view of Cetonia magnifica, showing many pollen grains on the body; 3. Cetonia magnifica in androecia;
|
|
4. Cetonia magnifica in gynoecia; 6. Some anthers above the gynoecia; 7. Cetonia magnifica in withered androecia; 9. Showing many pollen grains on the body of the bee after this bee visiting the flower; 5. Cetonia magnifica and bees in the same flower in Jishan population. |
|
|
|
Plate 111. under SEM 1. Pollen of Exochorda giraldii x1 800 2. Pollen of Paeonia suffruticosa subsp. spontanea x1 200 3. Pollen of Exochorda giraldii and Paeonia suffruticosa subsp. spontanea on surface of Hylovalgus bioculatus in Yongji populationx 480; 4. A few pollen grains on the curve of one leg of Hylovalgus bioculatus in Yongji population x60; 5. No pollen grains on the surface of the leg of Hylovalgus bioculatus in Yongji population x24; 6. Small beetle in Yongji population x24; 7. An enlarged portion of Fig.6, showing a few pollen grains on the body x120; 8. A portion of the leg of a bee in Yongji population, showing a large amount pollen grains x120; 9. An enlarged portion of Fig.8, showing pollen grains of Paeonia suffruticosa subsp. spontanea1 x200; 10. The head of a Cetonia magnifica from Jishan population,showing many pollen grains x60; 11. An enlarged portion of Fig.10,showing pollen grains of Exochorda giraldii x900; 12,13.under LM 12. Pollen grains of Exochora giraldii x192; 13. Pollen grains of Paeonia suffruticosa subsp. spontanea x128. |
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