Soybean and Bees

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According to Erbar (2003), there are numerous exudate-filled channels in the stigma and style, with pollen tubes growing in these channels, which provide nutrition and mechanical guidance. At the base of the stigma, in the transition zone between stigma and style, there is a gradual increase in the amount of exudate between cells, except in the center of the style. These cells comprise the stylar-transmitting tissue, secreting an exudate similar in appearance to that of the stigma. Pollen usually germinates on the surface of the film overlying the stigma exudate. Germination can also occur among the lower whorls of papillae, but these tubes then grow into the stigma before entering the style. Although many pollen grains are deposited on the stigma, and most of them germinate and grow into the stigma and upper style, the majority of the tubes atrophy and die before reaching the distal end of the ovary. Only a few pollen tubes reach the locule and compete for ovules to fertilize (Herrero and Hormaza, 1996). After germinating, pollen tubes grow between the cells of the stylar-transmitting tissue. The ovarian transmitting tissue forms a secretory obturator on top of which the pollen tubes grow toward the ovules (Erbar, 2003). Its exudate is pectinaceous, which perhaps controls the direction of pollen tube growth chemotactically (Cheung et al., 1995). During growth of the pollen tube toward the ovule, the generative cell divides and forms two male gametes, the sperm cells. Finally, the pollen tube grows through the micropyle of the ovule, between nucellar epidermal cells, and enters the filiform apparatus of the degenerate synergid. Here the pollen tube tip bursts and releases the two sperm cells. One sperm fuses with the egg and forms the diploid zygote, the first cell of the embryo, while the other sperm fuses with the secondary nuclei, forming the primary endosperm nucleus (Ray et al., 1997). Rustamova (1964) noted that the time from pollination to fertilization varies from about 8 to 10 h. Thus, the day of full opening of the flower is likely the very day of fertilization or, perhaps, is one day after fertilization. Soybeans are considered as cleistogamic, self-pollinating plants. The first studies indicated cross-pollination rate on soybeans to be as low as 0.04% in Wisconsin, with different varieties of soybean grown in adjacent rows, in different places (Woodworth, 1922), ranging from 0.70% and 0.18% in Virginia, in successive years (Garber and Odland, 1926), and less than 1% in Iowa and Maryland (Weber and Hanson, 1961). The cross pollination on soybeans is mediated by pollinators, especially the honeybee (Figure 19 and 20). 52 SoybeAn and bees
Figure 19. Apis mellifera visiting a soybean flower. Photo: Decio Luiz Gazzoni Photo: Decio Luiz Gazzoni Figure 20. Foraging bee covered by pollen grains. According to Ahrent and Caviness (1994), based on a 2-yr average, cross-pollination varied from a low of 0.09% for Walters cultivar to a high of 1.63% for ‘Brim’. The same authors mention that results show that cultivars differ significantly in the extent of cross-pollination and SoybeAn and bees 53
Page 1 and 2: SOYBEAN and BEES Decio Luiz Gazzoni
Page 3 and 4: Copies of this publication can be a
Page 5: Photo: Paulo Robson de Souza This b
Page 8 and 9: continuous development and use of p
Page 11 and 12: PREFACE Soybeans (Glycine max (L.)
Page 13 and 14: the pest abundance and the level of
Page 15 and 16: Table of Contents Soybean cycle....
Page 17 and 18: SOYBEAN cYCLE Soybean (Glycine max
Page 19 and 20: es from pod set to physiological ma
Page 21: Luckily for the growers - and for t
Page 24 and 25: The tassel starts to develop inside
Page 26 and 27: Flowers: Structure, anatomy and maj
Page 28 and 29: ing region is the throat and the fl
Page 30 and 31: Authors like Turck et al. (2008) as
Page 32 and 33: In the microgametogenesis, the unic
Page 34 and 35: dynamics, and the flux of ions are
Page 36 and 37: Once confirmed, agricultural practi
Page 39 and 40: Soybean reproductive development So
Page 41 and 42: Photos: Decio Luiz Gazzoni A B Figu
Page 43 and 44: Photo: Decio Luiz Gazzoni Photos: D
Page 45 and 46: monecious or dioecious flowers. Fig
Page 47 and 48: (Severson, 1983). He observed that
Page 49 and 50: stage. However, in spite of its res
Page 51: less prominent and quickly resemble
Page 55 and 56: Embryo, endosperm and seed coat dev
Page 57 and 58: Parallel to the embryo development
Page 59 and 60: Bees and plants relations Nectar, a
Page 61 and 62: with protection activity, as well a
Page 63 and 64: mental tobacco are expressed in the
Page 65 and 66: (2009) and its almost non-existence
Page 67 and 68: guided to particular flowers by flo
Page 69 and 70: crose, fructose, and glucose; domin
Page 71 and 72: Nectar, aroma and fidelity of polli
Page 73 and 74: Kram (2008) suggested a role in ant
Page 75 and 76: in seeds, particularly at intermedi
Page 77 and 78: legume nectaries. Species involved
Page 79 and 80: cium. These bodies vary somewhat in
Page 81: Trichomes and nectaries Gynoecium n
Page 84 and 85: soybean flowers. Also, van der Lind
Page 86 and 87: flowered varieties are inter-mixed
Page 88 and 89: Table 5. Differences on yield compo
Page 91 and 92: Pollinators foraging on soybeans Po
Page 93: Erickson (1984) questioned whether
Page 96 and 97: On the study of Chiari et al. (2013
Page 98 and 99: al. (1983). Conversely, lower N and
Page 100 and 101: the mean density did not reach the
Page 102 and 103:
The golden rule for minimizing nega
Page 104 and 105:
ALEXANDROVA, V. G.; ALEXANDROVA, O.
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BOLTEN, A. B.; FEINSINGER, P.; BAKE
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CARTER, C.; HEALY, R.; O´TOOL, N.
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CORBET, S. A.; DELFOSSE, E. Honeybe
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DZIKOWSKI, B. Studia nad soja Glyci
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FERRERES, F.; ANDRADE, P.; GIL, M.
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GALLAI, N.; SALLES, J. M.; SETTELE,
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GONZÁLEZ-TEUBER, M.; HEIL, M. The
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HEIL, M.; GONZÁLEZ-TEUBER, M.; CLE
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IVANOFF, S. S. KEITT, G. W. Relatio
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KLEIN, A. M.; STEFFAN-DEWENTER, I.;
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LINSKENS, H. F.; PFAHLER, P. L.; KN
Page 128 and 129:
MOFFETT, J. O.; STITH, L. S. Honeyb
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PAMPLIN, R. A. The anatomical devel
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RADHIKA, V.; KOST, C.; BOLAND, W.;
Page 134 and 135:
RUHLMANN, J. M.; KRAM, B. W.; CARTE
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TAKAHASHI, R.; MATSUMURA, H.; OYOO,
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VOGEL, S. Flowers offering fatty oi
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WIST, T. J.; DAVIS, A. R. Floral ne
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GLOSSARY Abaxial: Facing away from
Page 145 and 146:
Megaspores: In angiosperms, one of
Page 147 and 148:
Synergid: One of two small cells ly
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