Effects of inflorescence position on seed production and seedling establishment in Ligularia virgaurea

doi:10.3773/j.issn.1005-264x.2010.04.007

Abstract

Abstract:

Aims Position-effect of seeds within inflorescences of flowering plants is a common phenomenon, but its influence on seedling establishment is not well known. Our objective was to determine: 1) the pattern of seed production within inflorescences in Ligularia virgaurea (top, middle and bottom of inflorescences) and 2) if position-effect exists, whether it affects seed germination and seedling establishment.

Methods We surveyed seed production of L. virgaurea in the field, seed germination under an alternating temperature regime (15 °C / 5 °C; 12 h light/dark) in the laboratory and seedling establishment under 25% shade by potted plants in the field. One-way ANOVA was used to determine the effects of seed position on seed set, seed weight, ovule number, seed number, germination percentage, initial germination time, emergence percentage, survival percentage, root-shoot ratio (R/S), total biomass (TB) and net photosynthetic rate (P_n). Tukey’s test was used to determine the difference between average values.

Important findings Seed production of L. virgaurea is affected significantly by position within an inflorescence: seed set and seed mean weight are greatest at the top, mean number of ovules is highest at the bottom, and the middle position has the most seeds. Initial germination time is earlier for seeds from the bottom than top, germination percentage and emergence percentage are not significantly different among different positions, and survival percentage among three positions is nearly consistent. R/S and P_n are top > bottom, but TB is not significantly different. Seedling traits are consistent under two different rates of fertilizer application. Results imply that the seeds from different positions have inherently different germination and seedling growth strategies. Top seeds can disperse further and have stronger seedling establishment ability than bottom seeds. Therefore, top seeds have greater ecological significance for sexual recruitment, regeneration and colonizing new habitats.

Key words: germination, Ligularia virgaurea, positional effect, seed production, seedling traits

XIE Tian-Peng, DU Gou-Zhen, ZHANG Ge-Fei, ZHAO Zhi-Gang. Effects of inflorescence position on seed production and seedling establishment in Ligularia virgaurea[J]. Chin J Plant Ecol, 2010, 34(4): 418-426.

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URL: https://www.plant-ecology.com/EN/10.3773/j.issn.1005-264x.2010.04.007

https://www.plant-ecology.com/EN/Y2010/V34/I4/418

Figures/Tables 5

Table 1 Differences of seed production and germination traits among different positional capitulum within inflorescences

		结实率 Seed set (%)	胚珠平均数 Ovule mean number	种子平均数 Seed mean number	种子平均重 Seed mean weight (g)	萌发率 Germination percentage (%)	萌发开始时间 Initial germination time (d)
头状花序位置 Position of capitulum	df	2	2	2	2	2	2
头状花序位置 Position of capitulum	F	68.440	14.930	17.227	6.133	0.353	3.904
	p	***	***	***	**	ns	*

Fig. 1 Variation in seed production traits among different positions within inflorescences (mean ± SE). Different letter means significantly different among different positions (p < 0.05) according to Tukey’s test. A, Seed set. B, Seed mean weight. C, Ovule mean number. D, Seed mean number.

Table 2 Effects of different fertilizer supplies on seedling traits among different positional seeds within inflorescences

	df	出苗率 Emergence percentage (%)		存活率 Survival percentage (%)		根冠比 Root-shoot ratio		总生物量 Total biomass (g)		净光合速率(P_n) Net photosynthetic rate (μmol.m^-2.s^-1)
	df	F	p	F	p	F	p	F	p	F	p
种子位置 Position of seeds (P)	2	0.895	ns	0.138	ns	4.553	*	0.129	ns	53.429	***
施肥处理 Fertilize conditions (F)	1	0.028	ns	0.711	ns	0.331	ns	8.471	***	48.720	***
种子位置×施肥处理 P × F	1	0.821	ns	0.357	ns	0.179	ns	0.406	ns	11.262	***

Fig. 2 Variations in seed germination traits among different positions within inflorescence (mean ± SE). Different letters mean significantly different among different positions (p < 0.05) according to Tukey’s test. A, Germination percentage. B, Initial germination time. C, Emergence percentage. D, Survival percentage.

Fig. 3 Effects of different fertilizer supplies on seedling traits among different positional seeds within inflorescences (mean ± SE). Different letters mean significantly different among different positions (p < 0.05) according to Tukey’s test. A, Fertilize root-shoot ratio. B, CK root-shoot ratio. C, Fertilize total biomass. D, CK total biomass. E, Fertilize net photosynthetic rate. F, CK net photosynthetic rate.

References 37

[1]	Ashman TL, Hitchens MS (2000). Dissecting the causes of variation in intra-inflorescence allocation in a sexually polymorphic species, Fragaria virginiana (Rosaceae). American Journal of Botany, 87, 197-204. URL PMID
[2]	Berry PE, Calvo RN (1991). Pollinator dependence and position dependent fruit set in the high Andean Orchid Myrosmodes cochleare (Orchidaceae). Plant Systematics and Evolution, 174, 93-101.
[3]	Brunet J (1996). Male reproductive success and variation in fruit and seed set in Aquilegia caerulea (Ranunculaceae). Ecology, 77, 2458-2471.
[4]	Brunet J, Charlesworth D (1995). Floral sex allocation in sequentially blooming plants. Evolution, 49, 70-79. URL PMID
[5]	Buide ML (2004). Intra-inflorescence variation in floral traits and reproductive success of the hermaphrodite Silene acutifolia. Annals of Botany, 94, 441-448. DOI URL PMID
[6]	Buide ML (2008). Disentangling the causes of intra-inflores- cence variation in floral traits and fecundity in the hermaphrodite Silene acutifolia. American Journal of Botany, 95, 490-497. DOI URL PMID
[7]	Diggle PK (1995). Architectural effects and the interpretation of patterns of fruit and seed development. Annual Review of Ecology and Systematics, 26, 531-552.
[8]	Diggle PK (1997). Ontogenic contingency and floral morphology, the effects of architecture and resource limitation. International Journal of Plant Science, 158, 99-107.
[9]	Forbis TA, Doak DF (2004). Seeding establishment and life history trade-off in alpine plants. American Journal of Botany, 91, 1147-1153. URL PMID
[10]	Gordon DR, Rice KJ (2000). Competitive suppression of Quercus douglasii (Fagaceae) seedling emergence and growth. American Journal of Botany, 87, 986-994. URL PMID
[11]	Guitián J, Guitián P, Medranol M (2001). Causes of fruit set variation in Polygonatum odoratum (Liliaceae). Plant Biology, 3, 637-641.
[12]	He YL (何颜龙), Wang MT (王满堂), Du GZ (杜国祯) (2007). Seed size effect on seedling growth under different light conditions in the clonal herb Ligularia virgaurea in Qinghai Tibet Plateau. Acta Ecologica Sinica (生态学报), 27, 3091-3098. (in Chinese with English abstract)
[13]	Herrera J (1991). Allocation of reproductive resources within and among inflorescences of Lavandula stoechas (Lamiaceae). American Journal of Botany, 78, 789-794.
[14]	Hill MJ, Luck R (1991). The effect of temperature on germination and seedling growth of temperate perennial pasture legumes. Australian Journal of Agricultural Research, 42, 175-189.
[15]	Hiraga T, Sakai S (2007). The effects of inflorescence size and flower position on biomass and temporal sex allocation in Lobelia sessiliflora. Plant Ecology, 188, 205-214.
[16]	Houssard C, Escarré J (1991). The effects of seed weight on growth and competitive ability of Rumex acetosella from two successional old-fields. Oecologia, 86, 236-242. URL PMID
[17]	Kliber A, Eckert CG (2004). Sequential decline in allocation among flowers within inflorescences, proximate mechanisms and adaptive significance. Ecology, 85, 1675-1687.
[18]	Knight TM, Steets JA, Vamosi JC, Mazer SJ, Burd M, Campbell DR, Dudash MR, Johnston MO, Mitchell RJ, Ashman TL (2005). Pollen limitation of plant reproduction: pattern and process. Annual Review of Ecology, Evolution and Systematics, 36, 467-497.
[19]	Kubitzki K, Ziburski A (1994). Seed dispersal in flood plain forest of Amazonia. Biotropica, 26, 30-43.
[20]	Lee TD (1988). Patterns of fruit and seed production. In: Doust LL ed. Plant Reproductive Biology: Patterns and Strategies. Oxford University Press, New York 179-202.
[21]	Liu ZJ (刘左军), Du GZ (杜国祯), Chen JK (陈家宽) (2003a). Relationship between habitats and resource allocation of inflorescence structure in Ligularia virgaurea. Acta Phytoecologica Sinica (植物生态报), 27, 344-351. (in Chinese with English abstract)
[22]	Liu ZJ (刘左军), Du GZ (杜国祯), Chen JK (陈家宽), Liu ZH (刘振恒), Dong GS (董高生), Ma JY (马建云) (2003b). Factors influencing seed production in Ligularia virgaurea I. Habitat and architecture of inflorescence. Acta Phytoecologica Sinica (植物生态学报), 27, 677-683. (in Chinese with English abstract)
[23]	Medrano M, Guitián P, Guitián J (2000). Patterns of fruit and seed set within inflorescences of Pancratium maritimum (Amaryllidaceae): nonuniform pollination, resource limitation, or architectural effects? American Journal of Botany, 87, 493-501. URL PMID
[24]	Obeso JR (1993). Seed mass variation in the perennial herb Asphodelus albus: sources of variation and position effect. Oecologia, 93, 571-575. URL PMID
[25]	Paz H, Mazer SJ, Martinez RM (1999). Seed mass, seedling emergence, and environmental factors in seven rain forest Psychotria (Rubiaceae). Ecology, 80, 1594-1606.
[26]	Paz H, Martinez RM (2003). Seed mass and seedling performance within eight species of Psychotria (Rubiaceae). Ecology, 84, 439-450.
[27]	Raich JW, Khoon GW (1990). Effects of canopy openings on tree seed germination in a Malaysian dipterocarp forest. Journal of Tropical Ecology, 6, 203-217.
[28]	Reich PB, Oleksyn J, Tjoelker MG (1994). Seed mass effects on germination and growth of diverse European Scots pine populations. Canadian Journal of Forest Research, 24, 306-320.
[29]	Shan BQ (单保庆), Du GZ (杜国祯), Liu ZH (刘振恒) (2000). Clonal growth of Ligularia virgaurea: morphological responses to nutritional variation. Acta Phytoecologica Sinica (植物生态学报), 24, 46-51. (in Chinese with English abstract)
[30]	Susko DJ, Doust LL (2000). Patterns of seed mass variation and their effects on seeding traits in Alliaria petiolata (Brassicaceae). American Journal of Botany, 87, 56-66. URL PMID
[31]	Vallius E (2000). Position-dependent reproductive success of flowers in Dactylorhiza maculate (Orchidaceae). Functional Ecology, 14, 573-579.
[32]	Winn AA (1991). Proximate and ultimate sources of within-individual variation in seed mass in Prunella vulgaris (Lamiaceae). American Journal of Botany, 78, 838-844.
[33]	Wu GL (武高林), Du GZ (杜国祯) (2008). Relationships between seed size and seedling growth strategy of herbaceous plant: a review. Chinese Journal of Applied Ecology (应用生态学报), 19, 191-197. (in Chinese with English abstract)
[34]	Wulff RD (1986). Seed size variation in Desmodium paniculatum. I. Factors affecting seed size. Journal of Ecology, 74, 87-97.
[35]	Yanful M, Maun MA (1996). Effects of burial of seeds and seedlings from different seed sizes on the emergence and growth of Strophostyles helvola. Canadian Journal of Botany, 74, 1322-1330.
[36]	Zhang ST (张世挺), Du GZ (杜国祯), Chen JK (陈家宽), Xiong ZY (熊志远) (2003). Effects of seed weight on seedling growth under different nutrient conditions in twenty-four species of Compositae in an Alpine Meadow. Acta Ecologica Sinica (生态学报), 23, 1737-1744. (in Chinese with English abstract)
[37]	Zhao ZG, Meng JL, Fan BL, Du GZ (2008). Reproductive patterns within racemes in protandrous Aconitum gymnandrum (Ranunculaceae): potential mechanism and among- family variation. Plant Systematics and Evolution, 273, 247-256.