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Elina Yankova-Tsvetkova, Ivanka B. Semerdjieva, Rozalia Nikolova, and Valtcho D. Zheljazkov

microspore tetrads and anther wall, ( C ) one-nucleate pollen and anther wall, and ( D ) mature pollen grains and anther wall. Magnification ×400. spt = sporogenous tissue; mt = microspore tetrad; ep = epidermis; en = endotecium; ml = middle layer, t

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Kevin M. Folta

important plant traits are analyzed to the gene level, we find frequent evidence of parallel variability. Seed shattering. One of the best examples of common genetic factors contributing to a homologous series is kernel retention on seed heads in grains ( Li

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Michael T. Tesfaendrias, Mary Ruth McDonald, and Jon Warland

L. subsp. sativum ), onion ( Allium cepa L.), potato ( Solanum tuberosom L.), snap bean ( Phaseolus vulgaris L.), and sweet corn (for processing and fresh market) ( Zea mays L.) and one field crop: grain corn ( Zea mays L.). The Wisconsin

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Fabio Orlandi, Carlo Sgromo, Tommaso Bonofiglio, Luigia Ruga, Bruno Romano, and Marco Fornaciari

traps) powered directly in the field with solar panels and electric supplies ( Fig. 1 ). The daily average pollen concentrations (pollen grains/m 3 of air) were elaborated through laboratory techniques considering the pollen captured by the instruments

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W.G. Harris, M. Chrysostome, T.A. Obreza, and V.D. Nair

grain coatings ( Figs. 3 and 4 ). The effect of these coatings is a “variation on the theme” of soil texture. Their presence markedly increases moisture retention relative to sandy soils with no coatings ( Muchovej et al., 2006 ). That is because the

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Chao Gao, Deyi Yuan, Ya Yang, Bifang Wang, Dongming Liu, and Feng Zou

extended during blooming to accept as many pollen grains as possible ( Fig. 1D and E ). The styles were ≈12 mm in length, and the number of the styles ranged from four to five. Typically, the upper two-thirds region of the style was split apart ( Fig. 1F

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Ángel V. Domínguez-May, Mildred Carrillo-Pech, Felipe A. Barredo-Pool, Manuel Martínez-Estévez, Rosa Y. Us-Camas, Oscar A. Moreno-Valenzuela, and Ileana Echevarría-Machado

sections from three roots). Transverse sections also were stained with 0.5% (w/v) I 2 -KI (Lugol’s iodine staining) for visualization of starch grains by light microscopy as reported by Ponce et al. (2005) . Starch content. To determine the level of starch

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Shuang Han, Jiafu Jiang, Huiyun Li, Aiping Song, Sumei Chen, and Fadi Chen

were materially influenced by the level of incident light ( Fig. 5 ). The abundance of chloroplasts and the number of starch grains within each chloroplast were both inhibited by low light conditions. In cultivar Puma Sunny exposed to the “Shade

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Ojwang J. David, Nyankanga O. Richard, Imungi Japheth, and Olanya O. Modesto

important grain legumes ( Faris et al., 1987 ). In Kenya, pigeon pea is mainly grown for food and often used to supplement the cereal-based diets in rural areas where protein diets are deficient ( Omanga and Matala, 1987 ). Because of their availability, its

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Yinping Shi, Qiangsheng Wang, Jianming Yang, Congyi Sui, and Qingrong Sun

To perform apple polyploid breeding the ways of inducing polyploidy pollen with temperature and chemicals were studied. Materials include 13 diploid cultivars: Red Chief, Dai Hong, Rose Red, Golden Delicious, Mollie's Delicious, Gala, Bella, Jonathan, Fuji, Qiu Kou Hong, and Yan Qing, OBIR-2T-47. Chemicals: Chloroform, N-nitroso-ethylurea. At the beginning of PMC meiosis, fruiting branching groups were covered with plastic bags to raise temperature or were treated with chemical. After covering, temperature during the day increased 2 °C, generally not lower than 0 °C. Whether branches received high temperature or chemicals treatment, polyploidy pollen was induced to produce. The pollen grain of CK is tricolporat, its polar view is triangular, and its diameter almost 40 μm, showing no difference in size. Rate of empty pollen grain is low. Pollen grains that were treated were different in size, and rate of empty pollen is high, part of pollen grains germinating colporat change into tetracolporat with a few polycolporat, its polar view is square, round, and oval. The diameter of large pollen grains was 45-48 μm, increased by 11-12%. Giant pollen grain are 50-68 μm, increased by 25%-70%. Rate of induction is different in different cultivars. For most cultivars, giant pollen grain is 0.3%-0.5%. Gala and OBIR-2T-47 were higher, reaching 2.5%-7%. Chemicals caused damage on cultivars. Delicious strains were easily damaged.