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Reproductive Biology of Some Tropical Forest Species : Vikas kumar, vkskumar49@gmail.com

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From the forgoing presentation, it can be concluded that breeding characters viz., flowering period, inflorescence, time of flower opening, time of anther dehiscence, time of stigma receptivity, pollinating agent ,time of visitor of pollinating agent and fruit set (%) in tropical species are required to be studied as they are vital for any improvement and eco-environmental planning purposes. It also throws light on how species adopts itself along with the phenomenon of speciation and reproductive isolation. From these characters we can introduce new variety which is essential for further evaluation and also the identification of the interactions between biological factors, such as animal, plant species, and non-biological factors, like temperature, RH, rain and wind, helps us to elaborate management and conservation plans for the ecosystems of the planet, which have become more and more necessary due to highly increased rate of deterioration of different ecosystems during the last few decades.

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Reproductive Biology of Some Tropical Forest Species : Vikas kumar, vkskumar49@gmail.com

  1. 1. 1 Speaker:- M.Sc. (Forestry) Email id: vkskumar49@gmail.com
  2. 2.  Introduction  GLOSSARY  FLOWER STRUCTURE  POLLINATION  POLLEN MECHANISM  POLLEN BIOLOGY  POLLEN VIABILITY  POLLEN STORAGE  FERTILIZATION  Review of research work  Conclusion 2 OPEN CONTROL
  3. 3. Key words Angiosperms: (angios=container and sperms=seeds). The angiosperms are also known as plants with flowers.  Bryophytes: these are minuscule plants, mostly land-based, which differ from the other plants mainly because of the absence of true conductor vessels (xylem and phloem).  Caatinga: it is the only exclusively Brazilian biome, formed by a typical flora and fauna highly adapted to arid soils and climate.  Cerrado: it is a phytogeo graphical domain of the Savanna type that occurs in approximately 23% of the Brazilian territory.  Dispersion: process that makes possible the settlement of individuals of a species in places different from that where their parentals lived.  Nectar: aqueous substance produced by plants nectaries, like special glands and tricomas. Nectar is constituted mainly by sugars and is an important and nutritive food source to many animals.  Pollination: it is the transference of pollen from the anther to the stigma of the same vegetal species.  Proboscis: long and narrow mouth apparatus, highly adapted, used to withdraw nectar from flowers.  Dehiscent: fruit that naturally opens itself and releases the seeds.  Testa: part of the fruit originated from the wall of the ovary.  Pericarpum: external integument of the seed. 3
  4. 4.  Floral organs are thought to have evolved from leaves.  A complete flower has four whorls 1.Calyx, 2.Corolla, 3.Androecium and 4.Gynoecium  An incomplete flower lacks one or more of these whorls. 4
  5. 5. Stamen Anther Filament Carpel Stigma Style Ovary Ovule Petal Receptacle Sepal all stamens = androecium all carpels = gynoecium all petals = corolla all sepals = calyx 5 Figure 1: Flower Structure
  6. 6.  In a flowering plant the flower develops on the receptacle.  The buds of the flower are protected by sepals. Sepals are small leaves.  The petals of many flowers are brightly coloured which attracts insects.  These petals are often highly scented. Inside the flower there are pin-like structures called stamens.  The top of the stamen produces pollen cells, which contain the male sex cells. The club-like structure is the stigma. 6
  7. 7.  In the base of the stigma is the ovary.  The ovary contains ovules.  Each ovule contains a female sex cell. The carpel is made up of the stigma, style and ovary.  When the tip of the stigma is sticky it indicates that the carpel is ripe and ready to receive grains of pollen.  Flowers differ in external colour, size and shape. However they all have a similar internal structure. Some have carpels with one ovule, others have rows of ovules. CONTI….. 7
  8. 8. Flower types 8  Monoecious species present male and female flowers distributed in the same plant or individual.  Dioecious species have male and female flowers disposed in separated plants or individuals.  Hermaphrodite species possess hermaphrodite or bisexual flowers.  Gynomonoecious species bear female and bisexual flowers in the same individual.  Gynodioecious species present female and bisexual flowers in separated individuals.  Andromonoecious species have male as well as bisexual flowers distributed along the same plant or individual.  Androdioecious species possess male and bisexual flowers, but in different individuals.  Polygamous species bear male, female and bisexual flowers in the same individual.  Throughout the vegetal world, around 80% of the species bear hermaphrodite flowers and approximately 10% present individuals with separated genders. The remainder shows a lot of variation and some species have non-functional organs.
  9. 9. 9 Figure 2: Basic types of plants found in nature according to the sexual expression of the flowers. Polygamous plant.Dioecious plantMonoecious plant
  10. 10. 10 pollen grains Figure 3: Basic flower types found in nature Pollen sac filament Male flower Female flower Hermaphrodite flower
  11. 11. Ovary Position 12
  12. 12. CONTI…. 13
  13. 13.  New plants can grow in several ways: i. From seeds (sexual reproduction) ii. Producing things such as bulbs or tubers (asexual reproduction).  Tropical tree improvement programs basically depend on genetically superior seed crops that can be either obtained through open pollination or by controlled crossing.  In classical tree breeding it is achieved by establishing breeding populations such as clonal and seedling seed orchards. Though in open pollinated conditions it appears easy to harvest an optimal seed crop, under field conditions, it is difficult in most species.  It is mainly due to the reasons such as asynchronous flowering, flowering redundancy, self incompatibility, pollinator limitation and most often harsh climatic conditions.  Obtaining seeds through controlled crossing is also difficult because of inherent problems such as delicate flowers, high rates of flower and fruit abortions (Bawa and Webb 1984). 13
  14. 14. 14 Sexual Expression Frequency of Species Tropical forest Temperate forest Hermaphrodite 68% 7% Dioecious 10% 74% Monoecious 22% 19% Table 1: Sexual expression in species of Tropical and Temperate Forests. Brasil Bawa (1974).
  15. 15. • Pollen biology is of significance in tree improvement programmes as they decide gene flow and heterozygosity of populations which in turn decides genetic variability. • Pollens are reduced male gametophytes, upon pollination they produce tubes that grow through pistil tissues bringing in fertilization and seed set. • Pollen production and dispersal has both biological and genetic ramifications for the quantity and genetic quality of the seed produced. • Pollen grains differ in shape, number and position of germination pores. • These features are employed in identification and quantification of the pollen on the stigmas of open pollinated species, a measure to know effectiveness of pollination. 15
  16. 16.  Knowledge on pollen movement helps in determination of isolation distances and in establishment and management of seed orchards.  Quality of pollen is assessed by its viability and vigour.  Viability is the ability of pollen to deliver functional sperm cells to the embryosac following compatible pollination.  The period over which the pollen grain retains viability after release is highly variable as they are exposed to a wide range of environmental stresses particularly of temperature and humidity.  The time and rate of pollen shedding are also under the control of both external and internal factors.  In many species pollens get hydrated due to rain and causes loss of viability, bursting and precocious germination (Linskens et al. 1991). 16 CONTI…..
  17. 17. • Pollen viability is one measure of male fertility, they are generally conducted in breeding experiments and for monitoring the condition of stored pollen (Heslop- Harrison et al. 1989). • They are also used in identification of sterile hybrids where pollen is shrunk and infertile. • The method of collection and storage period affect viability (Shivanna and Johri 1985) and therefore any work requiring maximum viability of pollen should be conducted shortly after anther dehiscence. • Best results in controlled pollinated fruit set about < 90% can be obtained when fresh (1 day old) pollen is used. 17
  18. 18.  Since most tropical produce very sticky pollen, both collection as well storing is extremely difficult.  Till date controlled crossing using processed pollen have been performed only in Eucalyptus and Tectona grandis with varying success rates.  Extended period of pollen storage directly depends upon its nucleation.  Binucleate pollen have longer stored life when compared to trinucleate type.  Teak and Tamarind are typical binucleate pollens with one vegetative and a generative nuclei.  Using simple air drying method or silicate dessication and cold storage in 5° C allows Teak, Tamarind and Casuarina pollen to be viable and fertile up to 6 months. However there is a considerable fertility reduction when compared to fresh pollen. 18
  19. 19. Pollination is the process by which pollen is placed on the stigma. This must occur before a male sex cell can fuse with a female sex cell. There are a number of ways pollination can happen.  Self-pollination = Pollen from a flower’s anther pollinates stigma of the same flower.  Cross-pollination = Pollen from anther of one flower pollinates another flower’s stigma. -Also termed outcrossing. 19
  20. 20. Wind pollination = wind blows pollen from anthers of one plant to the stigmas of others. Plants that are wind pollinated are not usually brightly coloured, for example grasses. They do, however, have long filaments with anthers that hang down in the wind. They produce millions of pollen grains. The pollen is very light, some grains even have small air sacs to help them stay in the air longer. Insect pollination = when insects like bees carry pollen on their bodies as they move from flower to flower. The insects are attracted to the plants because the plants produce a sugary liquid called nectar which the insects like. The flowers of plants that are insect-pollinated tend to be brightly coloured, which makes it easy for the insects to find them. The pollen of these types of plant have large pollen grains and is a good food supply for the insects. Some pollen grains have spikes, which stick to the hair of insects. CONTI….. 20
  21. 21. Figure 4: Successful pollination in many angiosperms depends on regular attraction of pollinators. 21
  22. 22. 22 Figure 5: There are pollinators, as the "carpenter" bees (genus Xylocopa), which can fly more than 20 km. Being so, the gene flow among distant populations is incremented due to the search for a flower resource.
  23. 23. 23 Melittophily (Bees) Cantharophily (Coleoptera) Psychophily (Butterflies) Phalaenophily, Sphingophily (Moths) Myophily (Flies) Sapromyophiy (Carrion Flies) Ornithophily (Birds) Chiropterophily (Bats) Anthesis diurnal diurnal diurnal diurnal or nocturnal Diurnal diurnal diurnal nocturnal Color vivid colors, blue, white, yellow, orange, red, rose white, hues of very light green or yellow Red, blue, orange, yellow, pink (vivid colors) White or weakly colored Variable purple, color of exposed fleshy tissue scarlet, blue (vivid colors) light shades from white to cream Scent sweetish, refreshing strong, fruity weak, fresh, pleasant strong, sometimes sweetish imperceptible decaying animal protein weak, fresh, pleasant rancid, may resemble fermentation Flower shape standard, tube, campanula (bell- flower), brush, gorge, mechanically strong bowl, generally large or in numerous inflorescences, with many stamens and pistils tube, standard, gorge, brush, sometimes hanging tube, gorge, brush, sometimes hanging campanula (bell-flower), bowl, shallow or moderately concave dish or trap- like tubular tube, standard, gorge, brush, the ovary is protected by a solid wall brush, campanula (bell-flower), bowl, with one big single flower or many small flowers in strong inflorescences Symmetry plan radial or zygomorphic generally radial generally radial generally zygomorphic generally radial generally radial radial generally radial Nectar moderately hidden absent hidden in a long, thin tube with medium quantity hidden in a long, thin tube with medium quantity absent or present in small amounts absent in large amounts, moderately exposed in large amounts, moderately exposed Nectar guides present absent present, sometime complex usually absent present absent absent or simple absent Floral characteristics of the main pollination syndromes.
  24. 24. INSECT (Entomophily) Bees: fly showy, colorful, fragrant, with: nectar guides landing platforms Butterflies: fly showy, colorful, fragrant no nectar guides long tubes or spurs 24
  25. 25. Flies (Sapromyiophily) maroon / brown in color foul smelling (like rotting flesh) 25
  26. 26. Birds (Ornithophily): red (often) tubular 26 Figure 6: Examples of ornithophily. A: Aratinga aurea (Psittacideae) eating fruits of Oratea hexasperma (Ochnaceae); B: Aratinga ararauna Psittacideae) eating fruits of Brazilian Palmae.
  27. 27. Bats (Cheiropterophily): nocturnal anthesis large, colorful or white produce copious nectar or pollen 27 Figure 7: Bat pollination during the consumption of nectar. Siphocampylus sulfureus visited by Anoura caudifer
  28. 28. Wind (Anemophily): flowers small, numerous, often unisexual perianth absent or non-showy flowers often produced in mass 28 Figure 8: Examples of dispersion syndromes. Anemophily: A- seeds involved in silk cotton (Eriotheca gracilipes, Bombacaceae) and B- samaras (Peixotoa tomentosa, Malpighiaceae); Zoochory: C- fleshy fruit (Brosimum gaudichaudii, Moraceae).
  29. 29. 29 Figure 9: Generalist flower of the Cerrado cherry (Myrtaceae), exposing large quantities of anthers, accessible to all floral visitors. (Picture by Kleber Del Claro)
  30. 30. 30 Figure 10: Some example of the diversity of shapes, colors and floral resources available for the attraction of visitors and pollinators. Pollen flowers: A - Eriotheca gracilipes (Bombacaceae): B - Senna velutina (Caesalpiniaceae); Oil flower: C -Banisteriopsis malifolia (Malpighiaceae); Nectar flower: D - Jacaranda sp. (Bignoniaceae); compound flowers: E - Catlleya walkeriana and F -Schomburgkia crispa (Orchidaceae).
  31. 31. 31 Figure 11: An example of morphological features acting as a selective force upon pollinators. The flower of Odontadenia lutea (Apocynaceae) has a gamosepal corolla in a bottle-neck- like shape in the inferior part of the corolla (indicated under the arrow).
  32. 32. 32 Figure 12: Distribution of flowers from six species of the Malpighiaceae family along time in an area of Brazilian savanna. Each color represents a species of plant offering oil and pollen to the flower visitors. The consecutive flowerings provide the necessary resources to the maintenance of a guild of pollinators in the area in a determined time span. A p r i l
  33. 33.  Open pollination refers to the mating and reproductive success that happens in natural conditions.  Flower to fruit ratio and fruit to seed ratio are very low in most tropical trees (Bawa and Webb, 1984).  It is an inherent problem even in common species like Teak, (Kumar 1992) and Eucalypts (Moncur et al, 1995).  Attempts to enhance fruit and seed yield in Teak through application of growth regulators and insecticides have proved to be commercially non-viable.  Since Teak is a insect pollinated species introduction of apiaries was suggested (Nagarajan et al, 1996) as pollinator limitation is quite common in monocultures.  It has been proven to be successful in Phyllode Acacias and Eucalypts (Moncur et al, 1995). Based on the teak plantation targets and seed availability from breeding populations. 33
  34. 34.  Though successful controlled crossings have been carried out in many tropical trees (Bawa and Webb, 1984) only a few practically successful hybrid programmes have been reported so far (Eldridge and Griffin, 1983) due to technical difficulty.  Standardizing tree hybridization depends on a series of activities such as recording flowering phenology, knowing peak stigma receptivity, pollen collection and transfer.  Performance of controlled crossing on trees depends on the circadian rhythm exhibited by the trees.  Most tropical trees either flower in the early or late night.  Trees like Albizia lebbeck need to controlled pollinated 7.00PM to 2.00 AM, while teak can be worked between 8.00 - 11.00 am. 34
  35. 35. Species like Tamarind should be emasculated during late nights and can be pollen dusted in early mornings. Technical precision matters much in controlled pollinating tropical trees. For example fruit set increases in Eucalypts when cotton bags are used instead of paper bags for caging operated flowers. In species like Teak that have high rates of flower abortion with 6-7 hours of stigma receptivity bags can be removed on the same day of dusting shows higher fruit set. In species like Eucalyptus regnans the time between emasculation and dusting could be even eighteen days (Eldridge and Griffin, 1983). Using standardized controlled crossing techniques fruit set from 20 - 90 % can be obtained for any given species. CONTI….. 35
  36. 36. 36 Figure 13: plant pollinator mutualisms
  37. 37. Breeding systems How is it promoted? 1) Plant sex: dioecy (incl. gynodioecy, androdioecy, trioecy) Outbreeding = outcrossing / allogamy / xenogamy: 2) Difference in timing of floral parts = dichogamy protandry - male first protogyny - female first 37
  38. 38. Breeding systems Outbreeding = allogamy (outcrossing, xenogamy): 3) Spatial separation of anthers and stigmas = hercogamy 38
  39. 39. 4) Self-incompatibility Inability for fertilization to occur between gametes derived from one individual. 39
  40. 40. Inbreeding = selfing autogamy (within 1 flower) & geitonogamy (between fls. of 1 indiv.) Selective advantage: ensures propagule production Disadvantage: reduced to absent genetic variability allautogamy: both outcrossing & inbreeding e.g., Viola, Clarkia: two flower types: chasmogamous flowers - normal, open cleistogamous flowers - remain closed 40
  41. 41. Gamete Production: Plant sexual life cycles are characterized by an alternation of generations -Diploid sporophyte  haploid gametophyte  In angiosperms, the gametophyte generation is very small and is completely enclosed within the tissues of the parent sporophyte -Male gametophyte = Pollen grains -Female gametophyte = Embryo sac  Gametes are produced in separate, specialized structures of the flower. 41
  42. 42. • Angiosperms undergo a unique process called double fertilization. • A pollen grain that lands on a stigma forms a pollen tube that pierces the style. • While the pollen tube is growing, the generative cell divides to form 2 sperm cells. • When pollen tube reaches the ovule, it enters one of the synergids and releases the two sperm cells. • Then double-fertilization occurs. • One sperm cell nucleus fuses with the egg cell to form the diploid (2n) zygote. • Other sperm cell nucleus fuses with the two polar nuclei to form the triploid (3n) endosperm nucleus. • Eventually develops into the endosperm that nourishes embryo. 42
  43. 43. Growth of pollen tube Pollen tube Double fertilizationRelease of sperm cells Zygote (2n) Antipodals Polar nuclei Egg cell Synergids Endosperm nucleus (3n) 43 Figure 14: Structure of double fertilisation
  44. 44. 44
  45. 45. 45 Terminalia arjuna
  46. 46. Floral characters Observations Flowering period April-july Inflorescence Spike No. of flowers/ Inflorescence 45 ± 3.5 Flower Hermaphrodile, actinomorphic, epigynous No. of stamens 10 Perianth Gamotepalous with five tepals Time of flower opening 05:00-06:30 h Time of anther dehiscence 06:00-07:30 h Mode of anther dehiscence Longitudinal slit Pollen grains/anther 2120 ± 265 Pollen grains/flower 21200 ± 530 Pistil type Monocarpellary, unilocular Time of stigma receptivity 08:00-14:00 h No. of ovules/ovary 2 Ovule type Anatropous Table: 2 Floral characters of Terminalia arjuna 46B.R. Ambedkar University Agra Seema Chauhan et al. (2008)
  47. 47. Pollination mechanism No. of flowers pollinated No. of flowers set fruit Fruit-set (%) No. of fruits dropped off prematurely Fruit drop (%) 1. Autogamy (i) Unmanipulated 50 0 0 0 0 (ii) Manipulated 50 21 42 15 71 2. Geitonogamy 50 40 82 18 45 3. Xenogamy 50 48 96 0 0 Table: 3 Results of breeding systems in T. arjuna 47 B.R. Ambedkar University Agra Seema Chauhan et al. (2008)
  48. 48. Visitor species No. flowers visits/min. Length of a visit/sec. Pollen grains observed on different body parts N R ∑ SD N R ∑ SD N R ∑ SD Apis indica 10 12-18 15.0 4.5 10 1 - 4 2.5 1.2 10 740- 1750 1256 795 Apis florea 10 9-15 12.0 4.0 10 2-5 3.5 1.5 10 525- 1395 972 386 Pieris brassicae 10 7-11 9.0 3.0 10 4-13 8.5 2.0 10 436- 844 643 280 Danaus plexippus 10 6-10 8.0 2.5 10 5-14 9.5 2.2 10 405- 795 608 225 Vespa species 10 4-8 6.0 1.5 10 8-14 11.0 3.0 10 338- 610 480 175 Musca domestica 10 4-7 5.4 1.0 10 6-18 12.0 3.5 10 270- 325 299 128 Camponotus species 10 2-6 4.0 0.7 10 10- 16 13.0 4.0 10 190- 295 245 107 Table: 4 Foraging efficiency and pollen pick-up by insect species on T. arjuna. 48 N – No. of insects observed, R- Range, Ʃ Mean, SD- Standard deviation B.R. Ambedkar University Agra Seema Chauhan et al. (2008)
  49. 49. 49 Casuarina equisetifolia
  50. 50. 50 Table: 5 Variation in total Cone and seed production in single tree of C.equisetifolia population Seed source Cones Seeds Natural provenances Viti Levu, Fiji 1556.0 42,214 Cotonou, Benin 1239.0 40,150 Sarawak, Malaysia 1129.0 22,012 Ranong, Thailand 1070.0 28,135 Danger Piont, Australia 576.0 15,455 Kolombangara, Solomon Islands 451.7 12,960 Mariana Island, Guam 403.3 15,600 Wangetti Beach, Australia 196.0 5,944 Landraces Rameswaram, India 5817.3 2,02,132 Beihai, China 3446.6 1,59,320 Orissa, India 2819.0 1,04,788 Malindi, Kenya 633.7 23,029 Montazah, Egypt 214.0 7,785 Mean 1341.0 57,275 SE 561.0 CV % 72.4 Pondicherry Nagaranjan et al.(2001)
  51. 51. 51 Table: 6 Cone size and seed production in C. equisetifolia Seed source Cone size (cm) Seeds per Cone 1000 seed weight (gm) Width Length J O Mean J O Mean J O Mean J O Mean Cotonou 1.48 1.49 1.48 1.78 1.64 1.70 25.47 25.84 25.65 1.43 1.27 1.35 Danger Point 1.45 1.45 1.45 1.68 1.32 1.50 29.41 29.29 29.35 2.12 2.27 2.19 Wangetti Beach 1.10 1.18 1.14 0.90 0.94 0.92 25.20 26.33 25.77 1.12 1.32 1.22 Ranong 1.03 1.08 1.05 1.22 1.28 1.25 26.35 30.67 28.51 1.07 1.12 1.10 Sarawak 1.43 1.40 1.41 1.45 1.43 1.44 25.57 27.91 26.74 1.07 1.20 1.13 Solomon Island 1.14 1.13 1.14 1.04 1.04 1.04 29.36 31.75 30.55 1.05 1.13 1.09 Viti Levu, Fiji 1.14 1.18 1.16 1.22 1.40 1.31 26.53 29.63 28.08 1.01 1.14 1.08 Guam 1.21 1.16 1.19 1.44 1.39 1.41 33.04 36.91 34.98 1.45 1.10 1.27 Beihai, China 1.38 1.39 1.39 1.65 1.67 1.66 46.38 46.08 46.23 1.06 1.33 1.19 Malindi, Kenya 1.25 1.22 1.24 1.35 1.36 1.36 39.49 36.56 38.02 1.08 1.19 1.14 Egypt 1.07 1.06 1.07 1.21 1.24 1.22 31.68 31.99 31.83 0.78 0.82 0.80 Orissa, India 1.28 1.27 1.28 1.50 1.45 1.47 37.17 41.30 39.24 0.50 1.14 0.82 Rameswaram , India 1.498 1.49 1.49 2.05 2.01 2.03 45.40 48.29 46.85 1.36 1.57 1.47 Mean 1.27 1.27 1.27 1.42 1.40 1.41 32.39 34.04 33.22 1.163 1.276 1.219 SEd LSD CV % SEd LSD CV % SEd LSD CV % SEd LSD CV % Provenance 0.735 1.51 19.0 1.13 2.26 13.8 3.641 7.28 19 0.146 0.29 20.8 Season 0.295 0.59 0.44 0.89 1.428 2.86 0.057 0.11 Pondicherry Nagaranjan et al.(2001)
  52. 52. 52 Table: 7 Seed set and reproductive success in C. equisetifolia under open and controlled pollination Clone Pollination Seeds per Cone Seed felling (%) Germination (%) PERS TNIPT 7 open 48.4 90.2 61.5 0.805 cross 46.6 86.6 38.50 0.772 self 34.3 63.49 37.25 0.575 PY 119 open 42.8 93.0 90.17 0.855 cross 34.3 74.56 47.5 0.685 PY 42 open 67.4 90.59 67.5 0.846 cross 41.1 55.24 49.0 0.513 PY 75 open 34.8 93.29 83.5 0.868 cross 33.0 88.47 68.6 0.823 TNRM 2 open 44.7 87.13 78.2 0.744 cross 34.3 66.86 54.3 0.571 Pondicherry Nagaranjan et al.(2001) PERS = Pre-emergent reproductive success
  53. 53. 53
  54. 54. 54 Table :8 Reproductive attributes of Dalbergia sissoo Roxb. S. No. Component Average Range 1. Number of inflorescences per tree 14450 3,200- 20,000 2. Number of flower in an inflorescence 45 20- 75 3. Number of pollen grains per flower 3550 2,500- 4,000 4. Number of ovules per flower 5.0 3-8 5. Number of flowers in a tree 6,50,000 1,44,000- 9,00,000 6. Number of fruits/pods in an inflorescence 6.72 2- 26 7. Number of fruits /pods per tree 97,500 21,000- 1,35,000 8. Number of seeds per pod 1.30 1- 4 9. Number of seeds per tree 1,26,750 27,300- 1,75,500 Punjab University Chandigarh Vasudeva and Sareen (2011)
  55. 55. 55 Table: 9 Fruit and Seed formation as a result of Experimental pollinations and that formed in nature in D. sissoo Roxb. S. No. Type of Pollination No. of flowers Pollinated No. of pods formed Percentage pod formation No. of seeds formed per pod 1. Self-pollination 50 3 6 0.5 2. Crossing 50 22 44 2.4 3. Mixture crossing 50 24 48 2.6 4. In Nature 400 60 15 1.3 Punjab University Chandigarh Vasudeva and Sareen (2011)
  56. 56. 56 S. No. Branches Average number of flowers Average number of pods formed Average number of seeds formed 1. Upper 49.2 (30- 75) 7.4 (5- 9) 1.50 (1- 4) 2. Middle 45.4 (25- 72) 6.8 (5- 12) 1.30 (1- 4) 3. Lower 40.4 (20- 60) 6.0 (2- 12) 1.20 (1- 4) Average 45 6.72 1.30 Table :10 Production of flowers, pods and seeds in different canopies of middle aged tree of D. sissoo Roxb. Punjab University Chandigarh Vasudeva and Sareen (2011)
  57. 57. 57
  58. 58. 58 S. No. Time (hrs) Pollen viability (%) 1. 06.00 12.50 2. 07.00 25.00 3. 08.00 37.50 4. 09.00 56.25 5. 10.00 75.00 6. 11.00 75.00 7. 12.00 68.75 8. 13.00 62.50 9. 14.00 60.20 10. 15.00 56.25 11. 16.00 54.82 12. 17.00 50.00 13. 18.00 48.50 lsd (P<0.05) 10.00494 Table: 11 Pollen viability in different day time in Acacia nilotica (L.) Wild. Tamil Nadu Ganesan and Chandra (2009).
  59. 59. 59 Sucrose concentrations (%) % of pollen germination Pollen tube length (micrometer) 1 6.25 5 2 12.50 8 4 25.00 15 8 56.25 40 10 31.25 30 20 25.00 18 40 12.50 6 Table: 12 Optimum sucrose concentration for pollen in Acacia nilotica (L.) Wild. Tamil Nadu Ganesan and Chandra (2009).
  60. 60. 60
  61. 61. 61 Table: 13 Details of floral foragers, duration of flower handling, peak time of foraging and pollen load on their bodies Pollinator/ forager species Family Peak time of visitation (120 h) Flower handling time (s) (n = 20) Pollen load (n = 50) Thysanoptera Thrips hawaiensis Thripidae — 2 ± 1 Hymenoptera Apis dorsata Apidae 07. 30-08.30 hours 4.5 ± 1.8 254 ± 49 Apis indica 08.30-09.30 hours 4 ± 1.8 191 ± 32 Apis florea 07.30-08.30 hours 4.2 ± 2.1 179 ± 20 Apis cerana 07.30-08.30 hours 3.6 ± 1.6 196 ± 29 Apis mellifera 07.30-08.30 hours 2 ± 1.4 182 ± 49 Trigona sp 08.30-09.30 hours 5.8 ± 1.7 89 ± 23 Ceratina sp 08.30-09.30 hours 5.9 ± 1.6 76 ± 14 Lepidoptera Danaus chrysippus Danaidae 10.30-11.30 hours 4.5 ± 1.6 30 ± 17 Junonia almana Nymphalidae 10.30-11.30 hours 4 ± 1.7 12 ± 5 Pieris sp Pieridae 11.30-12.30 hours 4 ± 1.6 49 ± 22 Diptera Syrphid fly Syrphidae 09.30-10.30 hours 4.2 ± 0.6 80 ± 12 Unidentified insect — 09.30-10.30 hours 2 ± 0.4 32 ± 16 Delhi Vikas and Tandon (2011).
  62. 62. 62 Table: 14 Fruit set as a result of open and xenogamous pollination in the three populations. Population Fruit set (%) Open pollination Xenogamous Poliination NDU 4.8 12.1 NBW 3.7 14.4 NSO 4.1 11.8 Delhi Vikas and Tandon (2011).
  63. 63. 63 Jatropha curcas
  64. 64. 64 Table: 15 Time and occurrence of different phenological stages of Jatropha curcas Phenological stage First flowering span Second flowering span Flowering span April third week till June forth July second week till November second week Fruit initiation May third week July fourth week Opening of male flower 7.8 ± 0.31 days after bud formation 7.78 ± 0.69 days after bud formation Opening of female flower 9.7 ± 0.75 days after bud formation 10.9 ± 0.34 days after bud formation Fruit formation 26.5 ± 1.22 days after bud formation, 7- 9 days after anthesis 30.20 ± 2.00 days after bud formation, 7- 9 days after anthesis Fruit set (%) 37.0* 61.6* No. of fruits/inflorescence 5.2* ± 1.15, range 2- 14 10.6* ± 0.96, range 6- 16 No. of seeds per fruit 1.97* ± 0.16 2.7* ± 0.19 Unit seed weight (g) 0.22* ± 0.01 0.51* ± 0.05 Kernel wight (g) 0.10* ± 0.02 0.29* ± 0.01 Oil content (%) 25.4* 31.1* *Significant t value (p< 0.05) between two flowering seasons PAU, Punjab Kaur et al. (2011)
  65. 65. 65 Parameter Range Mean Male flower Length (cm) 1.10 – 1.40 1.20 ± 0.01 Breadth (cm) 0.60 – 0.90 0.76 ± 0.01 Female flower Length (cm) 1.10 – 1.90 1.60 ± 0.06 Breadth (cm) 0.71 – 1.1 1.01 ± 0.02 Male flower/inflorescence 86.5 – 151.4 117.4 ± 7.98 Female flower/inflorescence 6 – 16.6 13.5 ± 1.5 Male/female flower ratio 10.4 : 1 – 16.4 : 1 13.4 : 1 Pollens/anther 61.9 – 195.1 122.3 ± 11.5 Pollen size (µm) 80.2 – 89.5 85.5 Pollen viability (%) 58.2 – 79.4 71.6 ± 10.4 Table: 16 Morphology of flowers and pollens of J. Curcas PAU,Punjab Kaur et al. (2011)
  66. 66. 66 Table: 17 Fruit set in different breeding systems in controlled pollinations of Jatropha curcas Breeding system Fruit set (%) Number of seeds/fruit Cross pollination 93.2 2.4 Self pollination 72.2 1.3 Apomixes 36.3 1.6 Open pollination 79.2 2.6 CD 5 % 11.4 0.5 PAU Punjab Kaur et al. (2011)
  67. 67. 67 Pterocarpus santalinus (Fabaceae) Figure 17: Pollinator bees of P. santalinus. a, Apis dorsata; b, A. cerana and c, A. florea.
  68. 68. 68 Table: 18 Foraging efficiency and pollen pick-up by honeybees on P. Santalinus Visitor species No. of flowers visited Length of a visit Pollen grains found in body washings N R Ʃ SD N R Ʃ SD N R Ʃ SD Apis dorsata 10 12-18 15 2.56 10 1-6 3 1.4 10 850– 1860 1346 365 A. cerana 10 4-14 8 3.17 10 2-13 6 3.0 10 472– 1420 914 553 A. florea 10 6-12 9 1.92 10 4-15 7 3.9 10 340– 985 726 240 Tamilnadu Thangaraja and Ganesan (2008). N= Normal, R=Range, Ʃ = Mean.
  69. 69. 69 Figure 18: Day-to-day flower production of P. santalinus. Arrows indicate total absence or very less flowering.
  70. 70. 70 Table :19 Results of breeding systems in P. Santalinus Pollination mechanism No. of flowers Pollinated No. of flowers set fruit Fruit set (%) No. of seeds produced Seed set (%) No. of fruits dropped-off prematurely Fruit drop (%) Autogamy Unmanipulated Manipulated 50 0 0 0 0 0 0 50 12 24 12 50 10 83 Geitonogamy 50 34 68 34 50 20 59 Xenogamy 50 42 84 48 57 0 0 Tamilnadu Thangaraja and Ganesan, (2008).
  71. 71. 71
  72. 72. 72 Table: 20 Deposition of pollen grains on the stigma of T. paniculata S. No The day on which / after flower opening observation Range of pollen depositio n No. of pollen grains deposited on stigma Pollination efficiency Pollination success (in %) 1 The day on which flower opened 0 - 3 1.24 + 0.2182 0.000076 8 2 First day after flower opening 3 - 10 6.40 + 0.5363 0.00039 54 3 Second day after flower opening 6 - 26 13.48 + 1.2920 0.00083 72 4 Third day after flower opening 0 -1 0.98 + 0.26 0 0.2 Andhra University Rao and Solomon Raju (2002)
  73. 73. 73 Table: 21 Effect of different sucrose concentration along with BKM on the pollen germination and length of pollen tube in T. paniculata. S. No Sucrose with BKM (in %) Percentage of pollen germination Pollen tube length (mm) 1 Distilled Water 0 0 2 05 15.00 23.50 + 1.26 3 10 20.00 31.20 + 0.81 4 15 34.00 32.20 + 1.34 5 20 46.70 42.10 + 1.34 6 25 65.30 44.10 + 1.86 7 30 90.10 62.40 + 1.57 8 35 76.50 52.50 + 2.25 9 40 40.80 34.80 + 1.90 Andhra University Rao and Solomon Raju (2002)
  74. 74. 74 Gmelina arborea Roxb.  Gmelina arborea is a dry season bloomer.  It produces large, brownish-yellow, bisexual and zygomorphic nectariferous flowers.  The breeding system involves both self- and cross-pollination, but most of the self-pollinated flowers abort after two weeks of growth.  The floral characteristics suggest bee-floral syndrome, but bees, especially Xylocopa bees and passerine birds, pollinated the flowers. Figure 1. Gmelina arborea – A. Inflorescence; B. Mature bud; C. Open flower; D. Positions of sex organs. A B C D
  75. 75. 75 A B C D E F Figure 15. Gmelina arborea – A. Flower visitors: Xylocopa latipes; B. Redwhiskered Bulbul; C. Thickbilled flowerpecker;D. Initial fruit; E. Young fruit; and F. Ripe fruit.
  76. 76. 76 Table 22. Results of breeding systems in Gmelina arborea Pollination mechanism No. of flowers pollinated No. of flowers set fruit Fruit set (%) No. of fruits dropped-off prematurely Fruit drop (%) Autogamy Unmanipulated Manipulated 50 2 4 0 100 50 24 48 20 83.3 Geitonogamy 50 38 76 24 63.2 Xenogamy 50 46 92 0 0 NOTE- Hand-pollination results indicated that G. Arborea fruits through self- and cross- pollination. Even simply bagged mature buds without any manipulation for pollination produced fruit but fruit set rate is low. Andhra University Solomon Raju and Rao (2006)
  77. 77. 77 Figure 16. Natural fruit set rate in G. arborea. NOTE- However, most of the fruits that resulted from self-pollination were aborted after two weeks of growth. The natural fruit set rate at initial and young stage (after two weeks) is 14.5% and at fruit maturity 8.5%.
  78. 78. Tectona grandis 78 seeds
  79. 79. Table 23. Reproductive success rate in Teak. 79 Field of investigation Finding Reference Pollen fertility 99% fertility Nagarajan et al. (1996 b) Breeding system Weakly protandrous Rawat et al. (1992) Mating system analysis 98% out crossing Kertadikera and Prat (1995). Natural selfing rate 1.67% Nagarajan et al. (unpublished data) Controlled selfing rate 2.49% Tangmitcharoen and Owens (1996) Controlled crossing success rate 14.0% Tangmitcharoen and Owens (1996) Index of self incompatibility 0.17% Tangmitcharoen and Owens (1997) Pre-emergent reproductive success (PERS) 0.5% Palupi and Owens (1996) in open pollination PERS in open pollination 0.04% Nagarajan et al. (unpublished data) TNAU,Coimbatore Nagarajan et al. (2001)
  80. 80. 80 Insect visitors Order Family Species Relative*amount of teak pollen /insect Estimated number of insects observed Time of visitation Hymenoptera Anthophoridae Ceratina sp. 4 3 0800h—1700h Vespidae Polistes sp. 2 2 1000h—1400h Polistes sagitarrius Sauss. 2 2 1000h—1200h Polistes stigma Fabr. 2 2 1000h—1200h Vespa affinis (L.) 2 2 0800h—1000h Vespa velutina Lepeltier 2 2 1200h—1400h Formicidae — 0 1 1000h—1600h Apidae Apis mellifera 3 2 0800h—1200h Eumennidae Eumenes conica Fabricius. 2 2 1400h—1600h Eumennes esuriens Fabricius. 2 2 1400h—1600h Eumenes orchitectus Smith. 2 2 1400h—1600h Eumenes petiolata Fabricius. 2 2 1400h—1600h Eumenes sp. 2 2 1200h—1600h Diptera Calliphoridae Stomorhina lunata (Fab.) 4 0800h—1700h Lucilia sp. 3 1000h—1600h Tachinidae Dolichocolon sp. 3 1000h—1600h Sarcophagidae Sarcophaga sp. 3 1000h—1600h Syrphidae Eristalinus arvorum (Fab.) 2 1000h—1600h Otitidae Chrysomyza sp. 2 1000h—1600h Lepidoptera Hesperidae Iambrix salsala salsala Moore. 0 1 1400h—1600h Oriens sp. 0 1 1400h—1600h Pelopides sp. 0 1 1400h—1600h Lycaenidae Euchrysops paudava Horsf. 0 1 1400h—1600h Nacaduba sp. 0 1 1400h—1600h Nymphalidae Naptis columella martabana Moore. 0 1 1000h—1600h Precis almana almana (L.). 0 1 1400h—1600h Papilionidae Precis lemonias L. 0 2 1000h—1200h Atrophaneura aristolochiae aristolochiae Fabr. 0 1 0800h—1600h Pieridae Catopsilia pomona pomona-f hilaria stoll. 0 1 1400h—1600h Catopsilia pomona pomona-f pomona Fabr. 0 1 1200h—1400h Satyridae Delias hyparate ciris Fruhst. 1 1 0800h—1000h Eurema sp. 1 2 0800h—1200h Table :24 Insect visitors to Tectona grandis flowers collected at ASEAN Forest Tree Seed Centre, Saraburi, Thailand during 4 observation in July TNAU,Coimbatore Nagarajan et al. (2001)
  81. 81. 81 Fig. 17. Teak (Tectona grandis) the corolla abscised. Bar 5 mm.,six stamens and petals and straight style at receptivity (A); and (B) 1 d after receptivity after artially open anther at 13:00h, showing swelling of the epidermal cells which appear to contain secretory substances. Bar 0±4 mm. Fig. 3. Transverse section of anther as in Fig. 2 showing two microsporangia, each bearing two chambers. Bar 0±3 mm. EP: epidermal cell M: microsporangia; Scanning electron micrographs (SEM)) Corrola Microsporangia Anther
  82. 82. 82 Fig. 4. Inside of dehisced anther showing pollen and the secretion (*). Bar¯0±04 mm. Fig. 5. SEM of stigma papillae during receptivity with germinated pollen showingvarying degrees of hydration. Pollen tubes appear to have entered between the loose papillae. Bar 50 lm. . P: pollen, PT: pollen tubes
  83. 83. 83 Fig. 6. Floral nectaries at the base of the ovary. Bar 0±4 mm. Fig. 8. Nectariferous tissue during post-receptive period. Starch has been hydrolyzed leaving large vacuolate cells. Bars 0±03 mm. NE: nectary, SY: style , TT: hollow transmitting tissue ; OV: ovule. Fig. 7. Nectariferous tissue during the pre-receptive period characterized by darkly staining cells containing large amounts of starch (arrowhead). Bar0±03 mm.
  84. 84. 84 SEM micrographs during receptivity when style is relatively straight. Fig. 9. Forked stigma but lobes remain together. Bar 0±3 mm. Fig. 10. Splayed stigma. Bar 0±3 mm. ST: stigma, SY: style.
  85. 85. 85 From the forgoing presentation, it can be concluded that breeding characters viz., flowering period, inflorescence, time of flower opening, time of anther dehiscence, time of stigma receptivity, pollinating agent ,time of visitor of pollinating agent and fruit set (%) in tropical species are required to be studied as they are vital for any improvement and eco-environmental planning purposes. It also throws light on how species adopts itself along with the phenomenon of speciation and reproductive isolation. From these characters we can introduce new variety which is essential for further evaluation and also the identification of the interactions between biological factors, such as animal, plant species, and non-biological factors, like temperature, RH, rain and wind, helps us to elaborate management and conservation plans for the ecosystems of the planet, which have become more and more necessary due to highly increased rate of deterioration of different ecosystems during the last few decades.

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