Search Results

You are looking at 1 - 10 of 738 items for :

  • " Cucumis sativus " x
  • Refine by Access: All x
Clear All
Free access

Paul Jennings and Mikal E. Saltveit

Unlike horticulturally mature fruit of `Dasher II' and `Poinsett 76' cucumbers (Cucumis sativus L.), two cultivars that differ significantly in their level of chilling tolerance, imbibing and germinating seeds of these two cultivars responded similarly to chilling temperatures (e.g., increases in fresh weight, time to radicle emergence, and root growth). `Dasher II' and `Poinsett 76' seeds were imbibed and germinated at 10 to 30C, and seeds germinated at 25C for 24 h were chilled at 2.5C for various durations. In comparison, seeds from an aged lot of `Poinsett 76' seed (1989) responded very differently from the 1992 seed lots in all experiments. The chilling tolerance level of germinating `Poinsett 76' seed varied with the seedling age as measured by resumption of root growth. Our results suggest that some factor that confers chilling tolerance is gradually lost during the early stages of germination following imbibition.

Free access

Donavon Sonnenberg, Patrick A. Ndakidemi, Ambrose Okem, and Charles Laubscher

compared with the control. Table 1. Effect of drip irrigation on photosynthetic rate (A) between weeks 1 and 8 in Cucumis sativus . Table 2. Effects of drip irrigation on the transpiration rate (E) between weeks 1 and 8 in Cucumis sativus . Table 3

Free access

Yiqun Weng, Shanna Johnson, Jack E. Staub, and Sanwen Huang

Cucumber ( Cucumis sativus var. sativus L.) is an important and profitable processed vegetable product in many countries and a popular fresh market culinary component of human diets worldwide. In 2008, cucumber ranked fourth in total acres

Free access

Hybrid seed of cucumber (Cucumis sativus) is expensive to produce. Production of `artificial seeds' through somatic embryogenesis may be a viable alternative. Somatic embryos were induced, multiplied on a semisolid medium for 8-10 weeks, and germinated on agar-gelled medium before transplanting to soil. It was then important to determine the extent of variation among plants derived from somatic embryos. The criteria for variation among regenerants of cultivar Clinton were; plant height, fruit shape, fruit weight and number (yield/plant), days to first female flower and variation in selected isozymes. All measurements were taken on greenhouse-grown plants. Some regenerants of Clinton were also planted in the field and they flowered and, qualitatively, bore fruit as well as the zygote-derived plants. When quantitative measurements were made, variation was greater than for plants from zygotic embryos, but the visual impact was that there was little variation amongst regenerants. Regenerants grew more slowly and tended to yield higher numbers of slightly smaller fruits than plants from zygotic embryos. Average yield per plant was higher for somatic embryo-derived plants. For cultivar Corona only morphology of plant and fruit was examined. One plant was especially visually mutant and unacceptable as a commercial plant. The defects were readily identifiable in the seedling stage. Preliminary evidence suggests that `artificial seeds' of cucumbers may be a viable proposition.

Free access

Hybrid seed of cucumber (Cucumis sativus) is expensive to produce. Production of `artificial seeds' through somatic embryogenesis may be a viable alternative. Somatic embryos were induced, multiplied on a semisolid medium for 8-10 weeks, and germinated on agar-gelled medium before transplanting to soil. It was then important to determine the extent of variation among plants derived from somatic embryos. The criteria for variation among regenerants of cultivar Clinton were; plant height, fruit shape, fruit weight and number (yield/plant), days to first female flower and variation in selected isozymes. All measurements were taken on greenhouse-grown plants. Some regenerants of Clinton were also planted in the field and they flowered and, qualitatively, bore fruit as well as the zygote-derived plants. When quantitative measurements were made, variation was greater than for plants from zygotic embryos, but the visual impact was that there was little variation amongst regenerants. Regenerants grew more slowly and tended to yield higher numbers of slightly smaller fruits than plants from zygotic embryos. Average yield per plant was higher for somatic embryo-derived plants. For cultivar Corona only morphology of plant and fruit was examined. One plant was especially visually mutant and unacceptable as a commercial plant. The defects were readily identifiable in the seedling stage. Preliminary evidence suggests that `artificial seeds' of cucumbers may be a viable proposition.

Free access

N.M.P. Guedes and P.H. Jennings

To improve somatic embryogenesis of Cucumis sativus, two types of explants (cotyledons and stem sections) were cultured on Murashige and Skoog (MS) media supplemented with 2,4-D (2.0 mg·L–1) + kinetin (0.5 mg·L–1). After 4 weeks, the embryogenic callus was transferred for 2 weeks to MS + NAA (1.0 mg·L–1) for embryo development. Stem sections failed to develop embryos while cotyledons responded with 14% embryo formation. The embryos were transferred to MS without hormones for 4 weeks to allow for plantlet growth. These embryos developed only shoots. To improve on the successful generation of embryos with root and shoot development, the procedures used above were repeated, but the cotyledons were cut into three sections to be used as explants. Each transverse section of the cotyledon was approximately 2–3 mm wide. All sections produced callus but not all of them were embryogenic. From the first section (cotyledon base), the second (between the first and third section) and the third section (furthest from the cotyledon base), respectively, 58%, 31%, and 5% embryo development occurred. Those embryos from the basal cotyledon sections regenerated 10 plantlets, 5 with shoots and roots and 5 with only shoots. Approaches to enhance somatic embryogenesis, and shoot and root development, will be discussed.

Open access

Bao-Zhong Yuan, Zhi-Long Bie, and Jie Sun

The cucumber ( Cucumis sativus L.), which belongs to the Cucurbitaceae family, is a commonly consumed vegetable. It is an economically important crop that is widely cultivated throughout the world. Cucumber plants often experience biotic and

Free access

Toshio Shibuya, Akihito Sugimoto, Yoshiaki Kitaya, and Makoto Kiyota

material. Cucumber ( Cucumis sativus L. ‘Hokushin’) seedlings grown in a growth chamber for 12 d after seeding were used. The growth conditions were 30/26 °C (light/dark) air temperatures, 50% to 60% relative humidity, and a photosynthetic photon flux

Free access

Toshio Shibuya, Ryosuke Endo, Yuki Kitamura, Yoshiaki Kitaya, and Nobuaki Hayashi

light with high R:FR light on the potential photosynthetic advantage of transplants, we investigated the photosynthetic light responses of cucumber ( Cucumis sativus L.) seedlings grown under fluorescent lamps with high R:FR light and compared them with

Free access

Rebecca Grumet*, Xiaofeng Wang, Mohamed Tawfik, and Mitch McGrath

Genomics tools have become increasingly varied and valuable for crop improvement. While several species have been targeted for concerted genomic efforts, the majority of horticultural species have received limited attention. Despite the wide variety of important cucurbit crop species, the Cucurbitaceae family has had minimal effort. We have initiated projects to develop genomic tools for cucumber, Cucumis sativus L. Efforts include production of cDNA, yeast two-hybrid, and genomic libraries, and development of an EST database and website for cucumber genomics. Sequences of cucumber leaf ESTs so far indicate that the cDNA library is of high quality and has modest redundancy. Distribution of sequences, as nominally predicted from GeneBank BLAST analysis, indicates that expressed genes fall in the following general categories: photosynthesis (21%), DNA/RNA/protein synthesis (20%), metabolism (15%), signaling (5%), other (16%), and unknown proteins (23%). Cucumber sequence data have been deposited into GenBank and are available on the Michigan State Univ. website (http://genomics.msu.edu/cucumberdb). The yeast two-hybrid library has been successfully used to identify and characterize several genes based on interaction with key proteins of interest, including genes interacting with viral replicases and poly(A) binding protein. The genomic library has been verified to be of high quality and has been used to identify clones of interest.