Abstract
Acer oblongum is unique among maples because of the leaf structure and cryptic monoecy. In the present study, an in-depth investigation of reproductive biology has been carried out to study the pollination biology and breeding system of the tree species. The flowers show mixed characteristics of both entomophilous and anemophilous pollination in structure and pollen characteristics, respectively, and can thus be considered as ambophilous (exhibiting traits conducive to both insect and wind pollination). The wind was the primary means of pollination, but exclusion experiments showed that insects (Apis dorsata and syrphid fly) also facilitated pollination by 3–5%. The stigma of hermaphrodite flowers is located 2–3 cm above the level of indehiscent anthers. Interestingly, the insect pollinators hardly came in contact with the pistil; they only brought the pollen close to the stigma and shed it in its vicinity, to be trapped almost like the wind-borne pollen grains on the stigmatic papillae. Anthers of hermaphrodite flowers serve a relict function by attracting insect pollinators, but not contributing to self or cross-pollination. Fruit set following manual geitonogamous and xenogamous pollination showed a difference. The probable reason accounting for low fruit set seems to be the limited number of pollen donors (Staminate type II flowers), high pollen sterility, sparse distribution of individual trees, and geitonogamous pollen. Fruits are dry, indehiscent samaras. Mature fruits do not invariably bear seeds inside since hollow fruits are formed even when ovules inside remain unfertilized.
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References
- 1.
Moza MK, Bhatnagar AK (2007) Plant reproductive biology studies crucial for conservation. Curr Sci 92(9):1207
- 2.
Tandon R, Shivanna KR, Mohan Ram HY (2003) Reproductive biology of Butea monosperma (Fabaceae). Ann Bot 92(5):715–723
- 3.
Schemske DW, Husband BC, Ruckelshaus MH, Goodwillie C, Parker IM, Bishop JG (1994) Evaluating approaches to the conservation of rare and endangered plants. Ecology 75:584–606
- 4.
Moza MK, Bhatnagar AK (2005) Phenology and climate change. Curr Sci 89:243–244
- 5.
Morin X, Roy J, Sonie L, Chuine I (2010) Changes in leaf phenology of three European oak species in response to experimental climate change. New Phytol 186(4):900–910
- 6.
Carón MM, De Frenne P, Chabrerie O, Cousins SAO, De Backer L, Decocq G, Diekmann M, Heinken T, Kolb A, Naaf T, Plue J, Selvi F, Strimbeck GR, Wulf M, Verheyen K (2015) Impacts of warming and changes in precipitation frequency on the regeneration of two Acer species. Flora 214:24–33
- 7.
Kumar S, Tewari LM, Tewari A (2011) Phenological studies of two tree species Ilex dipyrena and Acer oblongum in Nainital Catchment, Kumaun Himalaya. Int J Sci Technol Manag 2(2):125–128
- 8.
Saeki I (2008) Sexual reproductive biology of the endangered Japanese red maple (Acer pycnanthum). Ecol Res 23:719–727
- 9.
Sullivan JR (1983) Comparative reproductive biology of Acer pensylvanicum and Acer spicatum (Aceraceae). Am J Bot 70(6):916–924
- 10.
Sakai AK (1990) Sexual reproduction of red maple (Acer rubrum) in northern lower Michigan. Am Midl Nat 123(2):309–318
- 11.
de Jong PC (1976) Flowering and sex expression in Acer L. A biosystematic study. Mededelingen Landbouwhogeschool, Wageningen
- 12.
Khushalani I (1963) Floral morphology and embryology of Acer oblongum. Phyton 10:275–284
- 13.
Sato T (2002) Phenology of sex expression and gender variation in a heterodichogamous maple, Acer japonicum. Ecology 83(5):1226–1238
- 14.
Peck CJ, Lersten NR (1991) Papillate stigmas in Acer (Aceraceae). Bull Torrey Bot Club 118(1):20–23
- 15.
Jacobs CA, Lersten NR (1994) Microsporogenesis and endothecial wall patterns in black maple (Acer saccharum subsp. nigrum, Aceraceae). Bull Torrey Bot Club 121(2):180–187
- 16.
Nayar MP, Shastry ARK (1987) Red data book of Indian plants. BSI, Calcutta
- 17.
Walter KS, Gillett HJ (1998) IUCN Red List of Threatened Plants. Compiled by the World Conservation Monitoring Centre. IUCN: The World Conservation Union, Gland, Switzerland, Cambridge
- 18.
Nayar MP, Datta A (1982) Fascicles of flora of India, fascicle 9 Aceraceae. Botanical Survey of India, Calcutta
- 19.
Yadav N, Pandey AK, Bhatnagar AK (2016) Cryptic monoecy and floral morph types in Acer oblongum (Sapindaceae): an endangered taxon. Flora 224:183–190
- 20.
Kearns CA, Inouye DW (1993) Techniques for pollination biologists. University Press of Colorado, Niwot
- 21.
Heslop-Harrison J, Heslop-Harrison Y (1970) Evaluation of pollen viability by enzymatically induced Fluorescence: intracellular hydrolysis of Fluorescein diacetate. Stain Technol 45:115
- 22.
Dafni A (1992) Pollination ecology: a practical approach. Oxford University Press, Oxford
- 23.
Wragg PD, Johnson SD (2011) Transition from wind pollination to insect pollination in sedges: experimental evidence and functional traits. New Phytol 191:1128–1140
- 24.
Peeters L, Totland O (1999) Wind to insect pollination ratios and floral traits in five alpine Salix species. Can J Bot 77(4):556–563
- 25.
Dafni A, Calder DM (1987) Pollination by deceit and floral mimesis in Thelymitran antennifera (Orchidaceae). Plant Syst Evol 158:11–22
- 26.
Linskens HF, Esser K (1957) Über eine specifische Anfärbung der Pollenschläuche im Griffel und die Zahl der Kallosepfropfen nach selbstung und fremdung. Naturweiss 44:16
- 27.
Zapata TR, Arroyo MTK (1978) Plant reproductive ecology of a secondary deciduous tropical forest in Venezuela. Biotropica 10(3):221–230
- 28.
IBM®, SPSS®, Amos™ 22. IBM Corp released 2013. Statistical Package for Social Sciences v. 22.0 IBM Corp., New York
- 29.
Bawa KS (1977) The reproductive biology of Cupania guatemalensis Radlk. (Sapindaceae). Evolution 31(1):52–63
- 30.
Abu-Asab MS, Peterson PM, Shetler SG, Orli SS (2001) Earlier plant flowering in spring as a response to global warming in the Washington, DC, area. Biodivers Conserv 10:597–612
- 31.
Mohandass D, Zhao J-L, Xia Y-M, Campbell MJ, Li Q-J (2015) Increasing temperature causes flowering onset time changes of alpine ginger Roscoea in the central Himalayas. J Asia Pac Biodivers 8:191–198
- 32.
Thakur P, Bhatnagar AK (2013) Pollination constraints in flowering plants—human actions undoing over hundred million years of co-evolution and posing an unprecedented threat to biodiversity. Int J Plant Reprod Biol 5(1):29–74
- 33.
Friedman J, Barrett SCH (2009) Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants. Ann Bot 103:1515–1527
- 34.
Linder HP (1998) Morphology and the evolution of wind pollination. In: Owens SJ, Rudall PJ (eds) Reproductive biology in systematics, conservation and economic botany. Royal Botanic Gardens, Kew, pp 123–135
- 35.
Ackerman JD (2000) Abiotic pollen and pollination: ecological, functional and evolutionary perspectives. Plant Syst Evol 222:167–185
- 36.
Culley M, Weller SG, Sakai AK (2002) The evolution of wind pollination in angiosperms. Trends Ecol Evol 17(8):361–369
- 37.
Friedman J, Barrett SCH (2008) A phylogenetic analysis of the evolution of wind pollination in the angiosperms. Int J Plant Sci 169:49–58
- 38.
Hesse M (1979) Ultrastruktur und Verteilung des Pollenkitts in der insekten- und windblu¨tigen Gattung Acer (Aceraceae). Plant Syst Evol 131:277–289
- 39.
Hall BA (1967) Flower structure and breeding systems in the maples. Gard J New York Bot Gard 17:84–89
- 40.
Hall BA (1951) The floral anatomy of the genus Acer. Am J Bot 38:793–799
- 41.
Freeman DC, McArthur ED, Harper KT, Blauer AC (1981) Influence of environment on the floral sex ratio of monoecious plants. Evolution 35:194–197
- 42.
Tamura S, Kudo G (2000) Wind pollination and insect pollination of two temperate willow species, Salix miyabeana and Salix sachalinensis. Plant Ecol 147:185–192
- 43.
Sacchi CF, Price PW (1988) Pollination of arroyo willow, Salix lasiolepis: role of insects and wind. Am J Bot 75:1387–1393
- 44.
Mangla Y, Tandon R (2011) Insects facilitate wind pollination in pollen-limited Crateva adansonii (Capparaceae). Aust J Bot 59:61–69
- 45.
Cruden RW (1977) Pollen-ovule ratios: a conservative indicator of breeding systems in flowering plants. Evolution 31(1):32–46
- 46.
Levin DA (1981) Dispersal versus gene flow in plants. Ann Mo Bot Gard 68:233–253
- 47.
Gleiser G, Verdú M (2005) Repeated evolution of dioecy from androdioecy in Acer. New Phytol 165(2):633–640
- 48.
Renner SS, Beenken L, Grimm GW, Kocyan A, Ricklefs RE (2007) The evolution of dioecy, heterodichogamy, and labile sex expression in Acer. Evolution 61:2701–2719
- 49.
Ross MD (1982) Five evolutionary pathways to subdioecy. Am Nat 119:297–318
Acknowledgements
The research was supported by the Ministry of Environment, Forest and Climate Change, New Delhi, as part of “All India Coordinated Research Project on Reproductive Biology of RET Tree Species” (No. 22/2/2010-RE) sanctioned to AK Bhatnagar, and by the Research and Development Grant from the University of Delhi to AK Pandey. Thanks are also due to Shri S.K. Dass for help in the preparation of photographic plates.
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Significance Statement
Acer oblongum is a threatened Himalayan tree species that is valued for its timber. The species is vanishing from its natural habitats due to anthropogenic activities and also due to a low regeneration rate. To know the reasons for poor regeneration in nature, it is important to study the reproductive biology of the species. This type of study is a prerequisite in developing a species-specific conservation programme.
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Yadav, N., Pandey, A.K. & Bhatnagar, A.K. Pollination Biology and Breeding System of Maple Species Acer oblongum Wall. ex DC. (Sapindaceae) Showing Mixed Syndromes of Wind and Insect Pollination. Proc. Natl. Acad. Sci., India, Sect. B Biol. Sci. 90, 489–500 (2020). https://doi.org/10.1007/s40011-019-01120-x
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Keywords
- Acer oblongum
- Cryptic monoecy
- Ambophilous
- Geitonogamy
- Pollen sterility
- Stigmatic papillae
- Xenogamy