Flowering phenology, floral strategies pollinator activity and breeding system were investigated in 14 species of the cerrado vegetation in Braeflia (DF), from April 1985 to April 1986 in Tabebuia caraiba (Mart.) Bur., T. ochracea (Cham.) Standl.; Erythroxylum campestre St. Hil., E. suberosum St. Hil., E. tortuosum Mart.; Diplueodon crulsianue Pohl., D. oblongus Pohl., D. ramosissimus Pohl., D. roomarinifolius St. Hil., D. villosus Pohl.; Kielneyera abdita Saddi, K. coriacea Mart., K. speciosa St. Hil. and K. variabilis Mart. The species occur sympatrically, often only a few meters apart, and conspecifics frequently occur in clumps. The majority of the species flowered during the dry season (May to August) except D. oblongue, D. villosue and K. speciosa which flowered during the wet season (December to March). Most of them flowered for several months except Tabebuia (one month). The most frequent flowering pattern was the "Cornucopian"' type, except for D. crulsianue and D. Villosus which were "Steady-State" types. Most congeners flowered synchronously, except K. speciosa which showed displacement. Flowers of all species are pollen donors (Tabebuia and Erythroxylum also have nectar rewards), but each genus presents specific floral strategies; Tabebuia, Massflowering, Erythroxylum, distyly and cauliflory, Diplueodon, enantiostyly and Kielmeyera, andromonoecy. Flowers were visited by a large spectrum of bees (38spp. ) and Erythroxylum were also visited by wasps (16 app. ). However, each genus had particular pollen vectors. Tabebuia; Centris and Bombus; Erythroxylum: wasps; Diplueodon; Apia and Trigona; and Kielmeyera; Xylocopa, despite the fact that other bees occur all year round. Controlled pollination experiments (self-, intraspecific-, interspecific crosses, tests for apomixis and from untreated bagged flowers), revealed that all species have a high outcrossing level and are selfincompatible. Only E. campeatre (shrub), D. crulsianus and D. villosus (hemixyles), showed some self-compatibility. Fluorescence microscopy indicated that pollen tubes from selfing and from interspecific cross pollinations were blocked in the ovary, suggesting that the selfincompatibility barrier operates late. Only in Erythroxylum the blockage occurred in the stigma (Thrum flowers) or in the style (Pin flowers). Fruit-set number from hand-pollinations and from natural pollination were low, but the former frequently yielded a higher number of fruits than the latter. Low fruit-set was associated with lack of resources allocated by the maternal parent for fruit maturation. In addition, it seemed that, in all species, many flowers were programmed to be pollen donors only, since they dropped without any sign of ovary enlargement even if they were hand-pollinated or were frequently visited by pollinators.

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Banana passionfruit (Passiflora mollissima) is a noxious weedy vine that is problematic in coastal regions throughout New Zealand. I investigated the pollination and dispersal mutualisms that facilitate its spread, in the Marlborough Sounds. Flower observations revealed that visits were almost exclusively from introduced honey bees and bumble bees, indicating an invasive mutualism. I investigated the pollination system of banana passionfruit by comparing fruit set, fruit size, seed set, germination success and the effects of inbreeding depression on seedlings when grown in competition, between hand-selfed, handcrossed, bagged and open flowers. Fruit set was significantly reduced when pollinators were excluded (3.0%) indicating reliance on pollinators for reproduction. While banana passionfruit is partially selfcompatible, fruit set was significantly reduced in selfed flowers (17.5%) compared to crossed flowers (29.5%), and we found significant pollen limitation (natural [18.0%] was significantly lower than crossed). A significant degree of inbreeding depression was apparent in germination success but not in fruit size, seed set or seedling growth and survival. Surprisingly, open flowers had significantly lower germination success (10.1%) than the other three treatments (crossed = 16.5%, selfed = 15.0%, bagged = 25.3%). Overall, natural flowers produce more seedlings per flower (1.7) than bagged flowers (0.9), but less than hand-selfed (3.0) and crossed (5.3) flowers. To investigate dependence on dispersal, germination success was compared between hand-cleaned seeds, fleshy seeds and intact fruits in the field and glasshouse. Seeds germinated readily in all treatments, with no significant difference between cleaned and fleshy seeds, so seeds do not require frugivore handling to germinate. In the field, tagged fruits were removed quickly after ripening. Significantly fewer fruit were wholly removed from off-road locations than locations on road edges, but removal rate was high in both cases (93% and 70%) indicating dispersal by both humans and wild animals. I found no evidence of dispersal by birds. Infra-red camera evidence revealed possums and rats consuming fruits in the field. In addition, 2818 seeds were extracted from 1.5 kg of pig excrement collected from Te Weu Weu Bay in February 2006. Seeds readily germinated following extraction from pig and possum droppings with a final germination success, in the glasshouse, of 45.6% and 53% respectively. None of the few intact seeds excreted by rats germinated. Therefore, together with direct weed control, limiting the spread of banana passionfruit through the control of pigs and possums may improve management success and reduce the spread of banana passionfruit.

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Bibliography: leaves 190-211. / xvi, 211 leaves, [24] leaves of plates : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Research was carried out to evaluate pollination efficiency, gene flow by pollen and fruit set in Packham Triumph cultivar pear trees located in a mixed planting of pear cultivars in a commercial orchard in the Coromandel Valley region of South Australia. / Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1999

Bibliography: leaves 190-211. Research was carried out to evaluate pollination efficiency, gene flow by pollen and fruit set in Packham Triumph cultivar pear trees located in a mixed planting of pear cultivars in a commercial orchard in the Coromandel Valley region of South Australia.

Stigmas of Arabidopsis thaliana carrying the exo70A1-1 mutation are defective in early pollen-pistil interactions; pollen grain adhesion to the stigma, pollen hydration, and penetration of the stigmatic surface by the pollen tube. Exo70 function in directed secretion has been linked to its ability to bind the phosphatidylinositides. To provide support that the classical, octomeric exocyst complex, which contains the Exo70 subunit, participates in compatible pollen-pistil interactions, this process was analyzed in plants deficient in Sec15, another subunit of the exocyst. Additionally, the role of phosphatidylinositol-4-phosphate (PI-4-P) in female fertility was evaluated through the use of the mutants ROOT HAIR DEFECTIVE 4-1 and PI4Kβ1β2 -/-, which have increased and decreased levels of PI-4-P respectively. Reduction of Sec15b levels or perturbation of PI-4-P in the stigma resulted in a reduced ability of of the transgenic/mutant stigmas to support pollen grain hydration; though all other stages of early pollen pistil interactions were unaffected.

Stigmas of Arabidopsis thaliana carrying the exo70A1-1 mutation are defective in early pollen-pistil interactions; pollen grain adhesion to the stigma, pollen hydration, and penetration of the stigmatic surface by the pollen tube. Exo70 function in directed secretion has been linked to its ability to bind the phosphatidylinositides. To provide support that the classical, octomeric exocyst complex, which contains the Exo70 subunit, participates in compatible pollen-pistil interactions, this process was analyzed in plants deficient in Sec15, another subunit of the exocyst. Additionally, the role of phosphatidylinositol-4-phosphate (PI-4-P) in female fertility was evaluated through the use of the mutants ROOT HAIR DEFECTIVE 4-1 and PI4Kβ1β2 -/-, which have increased and decreased levels of PI-4-P respectively. Reduction of Sec15b levels or perturbation of PI-4-P in the stigma resulted in a reduced ability of of the transgenic/mutant stigmas to support pollen grain hydration; though all other stages of early pollen pistil interactions were unaffected.

Originally Published: 1999; Revised / 3 pp. / Seed production for profitability is challenging. Cultural practices differ from those commonly used in forage production. This article outlines management recommendations that may help to accomplish profitable seed alfalfa yields.