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Raw seed, primed seed, and transplants were compared for effects on stand establishment, plant morphology, and yield of paprika pepper (Capsicum annuum L.) Raw seed seemed satisfactory for stand establishment, although primed seed had the potential to provide better initial stands. When populations were equalized, there were few differences in plant growth, plant morphology, or fruit yield attributed to seed treatment. Morphology of plants established by direct seeding generally was favorable for mechanical harvest. Use of transplants did not result in higher marketable fruit yields than direct seeding in two out of three years. When compared to plants established by direct seeding, three trends were consistent across all three years for plants established by transplanting: a) they were more massive: b) they had larger vertical fruiting planes: and c) they had more branches. These traits would increase the difficulty of mechanical harvest and would create the potential for more trash in the harvested product. Thus, transplanting is not recommended for stand establishment of paprika intended for mechanical harvest.
Nontreated seed, primed seed, and transplants were compared for effects on stand establishment, plant morphology, and yield of paprika pepper (Capsicum annuum L.). Nontreated seed was satisfactory for stand establishment, although primed seed had the potential to provide greater initial stands. When populations were made equal by thinning, there were few differences in stem and leaf dry weight, fruit yield, or plant morphology attributed to seed treatment. Generally, morphology of plants established by direct seeding was favorable for mechanical harvest. Using transplants did not result in higher marketable fruit yields than direct seeding in 2 of 3 years. When compared to plants established by direct seeding, three trends were consistent across all 3 years for plants established by transplanting: 1) they were more massive, 2) they had larger vertical fruiting planes, and 3) they had more branches. These traits increase the difficulty of mechanical harvest and create the potential for more leaves and stems (trash) in the harvested product. Thus, transplanting is not recommended for stand establishment of paprika pepper intended for mechanical harvest.
In order to gain an understanding of the capacity of severely shaded leaves to be productive in dense canopies, the effects of increased shading on morphology, dry-matter partitioning, and whole-plant net carbon exchange rate (NCER) were investigated on greenhouse-grown Vitis vinifera L. `Chardonnay' grapevines. Vines were subjected to whole-plant shading levels of 0%, 54%, 90%, and 99% of direct sun 3 weeks after potting. Data were collected 8 to 10 weeks after potting. Nonlinear regression was used to investigate the relationship of leaf morphological traits and organ dry weights to increased shading. Leaf size was maintained with increased shading to approximately the 90% shading level, while leaf fresh weight, volume, density, and thickness were immediately reduced with increased shading. Root dry weight was most affected by increased shading, and root to shoot ratio was reduced. When nonlinear regressions were produced for light response curves, light compensation point was reduced by approximately 49% by moderate shading, and 61% by severe shading. Shaded leaves approached the asymptote of the light response curve more quickly, and had reduced dark respiration rates, indicating that the morphological compensation responses by the vine allow shaded leaves to use available light more efficiently. However, the long-term ramifications of reduced root growth in the current year on vines with shaded leaves may be significant.
Linkage relations among eight isozyme genes, Acp-3, Est-1, Est-5, Prx-1, Prx-2, Prx-3, Me and Adh, and two morphological markers, Inh, and Twh, were investigated in one F2 and two BC1 families of interspecific crosses between the American chestnut (Castanea dentata) and the Chinese chestnut (C. mollissima). Inh was found to be consistently linked with Prx-1 and Est-5 in all families. The order of these three genes was determined to be-Ihn--Prx1--Est5. In addition, four other gene pairs, Acp3--Inh, Acp3--Prx1, Me--Inh and Twh--Inh were found to be linked in one of the three families investigated. The four isozyme genes and two morphological marker genes were tentatively integrated into one linkage group with the following gene order Acp3--Me--Twh--Inh--Prx1-Est5. This study demonstrated that isozyme genes can be integrated with morphological marker genes into a single linkage map without the need for additional crosses.
Pollen morphology was examined in amphidiploid and amphidaploid interspecific hybrids between Brassica oleracea L. and B. campestris L. Pollen of the amphidiploid interspecific hybrids between B. oleracea var. capitata and B. campestris var. pekinensis, and between B. campestris var. chinensis and B. oleracea var. capitata, were significantly longer and wider than those of their diploid parents, presumably due to the phenotypic expression of the hybrid genomes and ploidy effects. The exine ridges and pores of the amphidiploids were well-developed and significantly larger than those of their diploid parents, but they were poorly developed in the amphihaploids.
entire architectural phenotype in squash plants. Other traits associated with the bush growth habit include thicker main stems with reduced tendril production, longer petioles contributing to an upright canopy, cupped leaf morphology and, often, earlier
Grapevine under arid and semi-arid are subjected to low soil water availability, accompanied by high levels of temperature and severe transpiration in the summer period. In spite of their deep root system, severe water stress may occur during that period. Therefore, study of morphological and physiological responses of grapevine cultivars to water stress, especially during the different phenological stages, are necessary. The effect of water deficit stress on morphological and physiological responses of four Iranian grapevine cultivars (Vitis vinifera L. cvs. Bidaneh Sephid, Yaghooti Shiraz, Khoshnav, and Siaveh) were studied. This investigation was conducted as a factorial experiment in a complete randomized block design with four replications. In this study, 1-year-old own rooted vines were planted outdoor in plastic bags. Water stress was begun 115 days after bud break and contained for 2 months. Some vegetative and biochemical characters of leaves were evaluated; photosynthesis and gas exchange was measured. The results of analysis of variance indicated that water deficit stress decreased total dry weight, root dry weight, leaf area, non soluble carbohydrate concentration, and chlorophyll content. The reduction of leaf area in `Yaghooti Shiraz' and total dry weight and root dry weight in `Bidaneh Sephid' were higher than two other cultivars. Under water deficit stress condition, the soluble carbohydrate concentration and proline content in grapevine cultivars increased. Net photosynthesis and gas exchange rate were markedly reduced in water deficit stressed vines.
The colorful and pendulous inflorescence of Heliconia rostrata Ruiz & Pavon terminates an erect and herbaceous-musoid axis of a sympodial rhizome system. Each hapoxanthic axis bears a variable number of leaves (5 to 10) subtending the inflorescence. The number depends on the time between shoot emergence and flowering stimulus. Inflorescence initiation and development occurs without external evidence of this process until the inflorescence emerges from the pseudostem. The morphological changes occurring at the terminal shoot apex of the H. rostrata as it changes from vegetative to the flowering stage are described and illustrated by photomicrographs in this paper. The anatomical sections reveal that the apex on vegetative phase is domed, and a maximum of four furled leaves including one leaf primordium can be observed surrounding it. The growth of the leaf primordium is highly synchronized with growth of the most recently formed leaves. With the transition to inflorescence development, more primordia are observed on the apex, which ultimately give rise to the bracts. Except for the first sterile bract, a cincinnus primordium (flower cluster) is detectable in the axil when the next bract begins to develop. Flower differentiation on the cincinnus begins when many bracts are well-developed. The increase of longitudinal height on the internodes is among the first detectable morphological changes in the apex. Under inductive conditions, the transition to the reproductive stage is achieved early in plants with three or more unfurled leaves. The reproductive plant status is easier to detect under the microscope when the inflorescence has at least three bracts.
Experiments were performed to determine the influence of floral morphology and breeding behavior on flower longevity in Easter cactus. Four clones were used for this study: two clones (`Evita' and `Purple Pride') were highly self-incompatible (SI) and diploid (n = 11) and two other clones were self-compatible (SC) cytochimeras (diploid epidermis and tetraploid subepidermis) that were recovered from the diploid clones. There were clonal differences in the degree of herkogamy (spatial separation between anthers and stigma) and the stage of floral development in which autogamy commenced. Autogamy commenced on the day of anthesis in the `Evita' clones, but commenced ≈5 days after anthesis in the `Purple Pride' clones. Styles from undisturbed flowers were collected at senescence, fixed, and examined with epifluorescence microscopy. The SI diploid clones contained few pollen tubes at the base of the style, whereas the SC cytochimeras contained numerous pollen tubes at the base of the style. Among the `Evita' clones, flowers of the SC cytochimera senesced ≈3 days earlier the SI diploid. However, diploid and cytochimeral clones of `Purple Pride' were similar in flower longevity. Differences in flower longevity were attributed to clonal variation in breeding behavior and floral morphology. These data suggest that herkogamy should be used as a selection criterion when breeding for increased flower longevity in tetraploid (SC) Easter cactus.
Differences in foliar morphology and anatomy of hard maples (Acer saccharum Marsh. and Acer nigrum Michx. f.) may explain contrasting responses to moisture stress of these species. We conducted a 2-year study to examine leaf morphology and anatomy of populations of hard maples indigenous near the 43°N latitude from 94°W longitude in Iowa to the 71°W longitude in Maine. Leaves were collected from shoots exposed to direct solar radiation on multiple trees at each of 24 sites in 1995, and at 36 sites in 1996. Samples collected in 1995 showed stomate frequency on the abaxial leaf surface ranged from 380 to 760 stomata/mm2. Mean guard cell pair width and length were 16 and 17 μm, respectively. Stomate frequency related quadratically to longitude, was greatest for leaves from Iowa, and was negatively correlated with mean annual precipitation of the sample site. Leaf thickness did not vary with longitude and averaged 96 μm. Palisade thickness showed a greater correlation than mesophyll thickness to total leaf thickness. Mesophyll thickness was more highly correlated than palisade thickness to specific leaf mass, which did not vary with longitude and averaged 5.2 mg·cm–2. Analysis of leaves collected over both years showed trichome frequency and lamina area were related quadratically to longitude; the largest and most pubescent laminae were from westerly sites. These studies are being coordinated with greenhouse experiments on responses of seedlings from selected populations to moisture deficits.