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  • Author or Editor: R. E. Gough x
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In 1999, `Sweet Banana' pepper [Capsicum annuum L. (Grossum Group)] plants were grown under clean cultivation or with red, silver, or black polyethylene selective reflecting (SMR) mulches over the soil surface. Plants in each of three replications per treatment were field-set on 15 June. On 22 Sept., the plants were excavated and their root systems examined using a trench profile method and a succession of trench wall slices. The total numbers of roots of each plant at depths of 5, 10, 15, 20, and 25 cm and 10, 20, 30, 40, 50, and 60 cm from the plant stem were recorded. Distribution and architecture of the root systems were also examined. Plants grown under clean cultivation developed 50 to 60 adventitious roots each, while those grown under red mulch developed ≈20 and those under black and silver mulch about nine adventitious roots each. In all treatments, the adventitious roots radiated downward from the stem at an angle of 35° from the horizontal. No plants had vertical roots. Root system architecture was similar among treatments, with 40% of the roots in the upper 5 cm of soil and 70% in the upper 10 cm. Thirty percent of the roots were within 10 cm, 50% within 20 cm, and nearly 100% within 40 cm of the stem. Root numbers decreased with increasing depth and distance from the stem. The greatest number of lateral roots were produced under silver mulch, intermediate numbers under clean cultivation and black mulch, and the fewest roots under red mulch. Colored mulches influenced the total number of adventitious and lateral roots but not the root system architecture of pepper plants.

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In 1999, `Sweet Banana' pepper plants were grown under clean cultivation or SMR—red, silver, or black polyethylene mulches. Plants in each of three replications per treatment were field-set on 15 June. On 22 Sept., plants were excavated, and their root systems were examined. The total number of roots per plant at 5-, 10-, 15-, 20-, and 25-cm depths and 10-, 20-, 30-, 40-, 50-, and 60-cm distances from plant stems were recorded. Distribution and architecture of the root systems also were examined. Plants grown under clean cultivation developed 50 to 60 adventitious roots each, while those grown under red mulch developed about 20, and those under black and silver mulch about nine adventitious roots each. In all treatments, the adventitious roots radiated from the stem at an oblique, downward 35° angle. No plants had vertical roots. Root system architecture was similar among treatments, with 40% of the roots in the upper 5 cm of soil and 70% in the upper 10 cm. Thirty percent of roots were within 10 cm of the plant stem, and 50% were within 20 cm. Nearly 100% of the roots were located within 40 cm of the plant stem. Root count decreased with increasing depth and distance from the plant stem. Plants grown beneath the silver mulch produced the greatest number of lateral roots, followed by plants grown in clean cultivation and under black mulch. Plants grown under red mulch produced the fewest roots. Differences among treatments were significant. Colored mulches influence the total number of adventitious and lateral roots but not the root system architecture of pepper plants.

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Abstract

Mature bushes of several cultivars of highbush blueberry (Vaccinium corymbosum L.) were left unpruned or pruned on September 16, November 15, and February 15 in each of 3 years. Plants left unpruned usually reached full bloom first. Plants pruned in September usually attained full bloom last, while those pruned in February bloomed earliest, shortly after those that were not pruned. Pruning resulted in an average delay in full bloom of from 0–5 days.

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Abstract

Fertilized portions of 1-year-old plants of ‘Berkeley’ blueberry (Vaccinium corymbosum L.) displayed significantly greater shoot dry weight, shoot thickness, leaf dry weight, and mean number of shoots than unfertilized portions. Fertilized portions blossomed and produced fruit while flower buds on the unfertilized portions died.

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Abstract

The root system of the cultivated highbush blueberry (Vaccinium corymbosum L.) is primarily composed of fine, thread-like roots less than 1 mm in diameter. Essentially all of the roots of 7-year-old ‘Lateblue’ bushes were located within the area between the crown and the dripline. Most of the roots on 13-year-old ‘Coville’ bushes were also within this area. Roots were found 180 cm from the crown and at depths of 81 cm. Roots were in the decomposing low layers of the sawdust mulch but not within the upper, non-decomposing layers.

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Abstract

Stone cells of highbush blueberry (Vaccinium corymbosum L.) were distributed primarily toward the periphery of the fruit; they apparently differentiated from ground parenchyma shortly after anthesis. Secondary cell wall material continued to be accreted through harvest, with lamellations about 1μm in width. The lignified walls were heavily pitted, with pits contiguous with those of adjacent stone cells. The number of stone cells may be correlated positively to the length of the growth season for each cultivar.

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The herbicidal activity of wheat gluten meal (WGM) was evaluated on 17 species of monocotyledons and dicotyledons. Treatments included WGM at 0, 1, 2, 3, 4, 6, and 9 g·dm-2. Germination, shoot and root lengths, and root numbers were recorded. Treatments reduced germination and root extension in nearly all species. Leafy spurge (Euphorbia esula L.), redroot pigweed (Amaranthus retroflexus L.), shepherd's purse [Capsella bursa-pastoris (L.) Medik.], henbit (Lamium amplexicaule L.), quackgrass [Agropyron repens (L.) Beauv.], annual bluegrass (Poa annua L.), Canada thistle [Cirsium arvense (L.) Scop.], orchardgrass (Dactylis glomerata L.), purslane (Portulaca oleracea L.), annual ryegrass (Lolium multiflorum Lam.), and snap bean (Phaseolus vulgaris L.) were particularly sensitive. Germination of curly dock (Rumex crispus L.) and common lambsquarters (Chenopodium album L.) was suppressed at the higher rates. Germination of black medic (Medicago lupulina L.), spotted knapweed (Centaurea maculosa Lam.), mustard (Brassica sp.), and corn (Zea mays L.) were not substantially affected at any rate. Shoot growth of all species was inhibited at rates >2 g·dm-2, and at the highest rates no shoots developed. In nine species, shoot extension was stimulated at 1 g·dm-2 WGM. The herbicidal activity of WGM was not due to a “mulching” effect, since growth characteristics were also altered in bean seeds barely covered by the treatments.

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Abstract

Leaves of cultivated highbush blueberry (Vaccinium corymbosum Ait.) displayed a markedly altered anatomical structure following sprays of succinic acid −2,2-dimethylhydrazide (daminozide, SADH). Alterations include an increased number of stomata per unit area, increased length of palisade cells, and a larger, more distinct secondary palisade layer and total spongy mesophyll complex, both of which contributed to increased lamina thickness.

Open Access
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Abstract

Berry/pedicel abscission zone formation in cultivated highbush blueberry (Vaccinium corymbosum L.) during fruit ripening appeared at the distal portion of the transition zone (disc) separating the berry and the pedicel. The abscission zone was first evident as a compressed zone of cells at the periphery of the berry/pedicel junction in the immature green stage of berry development. Cell separation initially appeared during the green-pink berry stage concomitant with berry coloration. Separation was characterized primarily by cell wall rupture. No separation layer was formed through either the berry epidermis or the vascular bundles. The number of berries without attached pedicels separating from the cluster under applied force was closely related to the stage of ripening of the fruit. Stresses imparted during ripening by rupturing internal tissues are evident in definite morphological changes appearing on the surface of the fruit.

Open Access

Abstract

Roots of flooded highbush blueberry (Vaccinium corymbosum L.) plants examined by light and scanning electron microscopy exhibited enlarged epidermal cells, compressed cortical cells, and disrupted vascular tissue. The stems of flooded plants showed disrupted epidermal tissue, condensed outer cortical cells, and large aerenchyma-like mid-cortical tissue. Leaves from flooded plants showed an increase in intercellular spaces in the spongy mesophyll and a disrupted palisade layer. There were no apparent differences in inflorescence bud anatomy, although inflorescences were small and delayed in development.

Open Access