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The perisperm–endosperm (PE) envelope surrounding the embryo of cucumber (Cucumis sativus) acts as a barrier to apoplastic permeability and radicle emergence. The envelope consists of a single cell layer of endosperm whose outer surface is covered by noncellular lipid and callose-rich layers. We compared the structure and histochemistry of the radicle tip and chalazal regions of the envelope, because these regions differ in permeability. Seeds were treated with coumarin 151, a nonionic, fluorescent tracer with systemic activity. Treated seeds were imbibed and on seedcoat removal, the root tip area of the membrane-covered embryo accumulated the fluorescent tracer, but the tracer could not penetrate the envelope that bordered the cotyledons and chalazal region. The cone-shaped remnant of tissue opposite the micropylar region of the envelope was identified as nucellar tissue, the “nucellar beak.” The cuticular membrane and callose layer of the PE envelope were interrupted in the nucellar beak as well as in the chalazal region. Their role in permeability is apparently substituted by the presence of thick-walled suberized cells in the beak and chalaza. A canal was observed in the center of the nucellar beak that likely provided a conduit for the tracer to diffuse from the environment to the embryo. This canal was the remnant of pollen tube entry through the nucellus and was plugged with several cells, presumably residue of the suspensor. These cells degenerated just before cucumber seed germination. This remnant of the pollen tube canal presumably offers less mechanical resistance in the nucellar beak that might help facilitate radicle protrusion during germination. Cells of the outermost and basal regions of the nucellar beak as well as the walls of endosperm cells contained pectic material. Significant pectin methylesterase activity was found in the lateral and cap regions of the PE envelope long before seed germination. Lack of callose in the envelope at the radicle tip suggests that callose does not act as a barrier to radicle emergence during cucumber seed germination.

Weed management can be difficult and expensive in organic agricultural systems. Because of the potentially high cost of the natural product herbicides vinegar and clove oil, their efficacy with regard to weed species growth stages needs to be determined. A further objective was to identify anatomical and morphological features of redroot pigweed and velvetleaf that influence the effectiveness of vinegar and clove oil. Research was conducted on greenhouse-grown cotyledon, two-leaf, and four-leaf redroot pigweed and velvetleaf. Dose–response treatments for vinegar included 150-, 200-, 250-, and 300-grain vinegar at 318 L/ha and at 636 L/ha. Clove oil treatments included 1.7, 3.4, 5.1, and 6.8% (v/v) dilutions of a clove oil product in water (318 L/ha), and a 1.7% (v/v) dilution in 200-grain vinegar (318 L/ha). An untreated control was included. Separate plantings of velvetleaf and pigweed were treated with vinegar or clove oil and were used to study anatomical and morphological differences between the two species. Redroot pigweed was easier to control with both products than velvetleaf. Whereas 200-grain vinegar applied at 636 L/ha provided 100% control (6 d after treatment [DAT]) and mortality (9 DAT) of two-leaf redroot pigweed, this same treatment on two-leaf velvetleaf provided only 73% control and 18% mortality. The obtuse leaf blade angle in velvetleaf moved product away from the shoot tip, whereas in pigweed, the acute leaf blade angle, deep central leaf vein, and groove on the upper side of the leaf petiole facilitated product movement toward the stem axis and shoot tip. For both species, and at all application timings, 150-grain vinegar at 636 L/ha provided control equal to that of 300-grain vinegar at 318 L/ha. As growth stage advanced, control and biomass reduction decreased and survival increased. Application timing will be critical to maximizing weed control with vinegar and clove oil.

The objective of this study was to determine how nitrogen (N) supply affects the source-sink balance and fruit size of ‘Gala’ apple when crop load was controlled at a moderate level. Five-year-old ‘Gala’/‘M.26’ trees grown in sand culture and trained in tall spindle received a total of 3.3, 10.0, 20.0, or 40.0 g actual N through fertigation using Hoagland's solution from bloom to 3 weeks before harvest. The crop load of these trees was adjusted to 6.5 fruit/cm2 trunk cross-sectional area by hand thinning when the diameter of the largest fruit was 10 mm. As N supply increased, total shoot leaf area in the canopy increased, whereas total spur leaf area remained unchanged. Both single leaf and whole canopy net CO2 assimilation rates increased with increasing N supply. The net dry matter gain of the whole tree from budbreak to fruit harvest increased ≈74% from the lowest N supply to the highest N supply, but the proportion of net dry matter gain partitioned to fruit (harvest index) decreased from 83% to 70%. Both leaf area to fruit ratio and average final fruit size increased with increasing N supply, and a linear relationship was found between leaf area to fruit ratio and final fruit size. The number of cells per fruit increased with increasing N supply, whereas average cell size remained unchanged. As N supply increased, fruit soluble solids concentration increased, whereas fruit firmness decreased slightly. These results indicate that 1) apple trees grown under low N supply are source-limited; and 2) within the range of N supply used, increasing N supply improves leaf N status, leaf and whole tree photosynthetic capacity, and leaf area to fruit ratio, leading to more cells per fruit, larger fruit, and higher soluble solids.

The objective of this research was to determine the effect of water temperature during spring and fall floods on nonstructural carbohydrate concentration and anatomy/morphology of ‘Stevens’ and ‘Early Black’ cranberry vines. Potted vines of each cultivar were subjected to either a simulated 1-month late water (LW) flood in the spring at either 11 or 21 °C or a simulated 1-week harvest flood in the fall at either 12 or 20 °C. Higher water temperature resulted in decreased total nonstructural carbohydrate concentration (TNSC) during the LW flood in both uprights (i.e., vertical shoots) and roots of ‘Early Black’ and ‘Stevens’. The effect of water temperature was much less during the harvest flood than during the LW flood, but flooding at either temperature during the harvest flood had an impact on TNSC, whereas for LW floods, high water temperature was more influential than low water temperature. Clumping of chloroplasts in the palisade layer and occlusion of vascular tissues was observed in the leaves of both cultivars as a result of LW flooding. Some epidermal erosion and formation of a fungal mat was apparent on the upper epidermis of some flooded leaves. Senescence in some fine roots was visible after harvest flooding, more so in vines flooded at 20 °C than at 12 °C. Stems and major roots showed no influence of flooding on tissue senescence.

Field and greenhouse studies were conducted from 1997 to 2001 to determine cabbage response to posttransplant applications of pendimethalin (0.56 to 2.24 kg ai/ha). Differential variety response was minimal, and applications greater than 0.56 kg caused severe and persistent crop injury and reduced head number and yield in ‘Azan’, ‘Storage 4’, ‘Super Elite’, and ‘Super Red 90’. Pendimethalin (1.7 kg) applied posttransplant reduced cabbage yield weights 23, 30, and 87% with bare root, large, and small transplants, respectively. Application (0.84 kg) to soil, foliage, or soil and foliage caused 0, 81, and 82% dry weight reduction by 21 d after treatment, respectively. Anatomical analysis of two-leaf seedlings collected 3 wk after pendimethalin treatment (1.12 kg ai/ha) showed stunting of the shoot apical meristem and its emerging leaves, disorganization of apical structure with disruption of normal cell division and cell expansion, and abnormal differentiation of the vasculature in leaves and hypocotyls. Nom...

The histology of external CO2 injury of the skin of `Empire' apples and postharvest factors affecting occurrence of injury were investigated. Injury was greater in a 5% CO2/2% O2 atmosphere than in 2% CO2/2% O2, but incidence was affected by orchard source. Susceptibility to injury was highest during the first 4 weeks of storage, while a postharvest treatment with diphenylamine prevented the disorder. Ethanol reduced injury, but ascorbic acid increased incidence of the disorder. Keeping fruit in air cold storage for 10 days before application of CO2 markedly reduced incidence of CO2 injury. Histological studies showed that external CO2 injury begins at the hypodermis—cortex boundary and spreads outward into the upper hypodermis and inward into outer cortex cells, although the cuticle and epidermis appear unaffected and unbroken. Radial walls of affected cells collapse and become pleated, so that the skin surface sinks below nearby normal regions. Other cellular events include loss of cytoplasmic integrity, coagulation of the protoplast, loss of organelle structure, and cell wall separation. Nondigested starch can be found in cells of affected fruit at the hypodermis—cortex boundary. We conclude that several factors affect fruit susceptibility to CO2 injury, including orchard, antioxidant treatment, and delays before application of CO2.

SummaryA stereological method was developed to analyze the anatomical features of fresh ‘Empire’ apple fruit sectors cut in the transverse equatorial plane. Fruits were from unthinned trees or trees hand-thinned to one fruit per cluster at –7, 0, 10, 20 or 40 d after full bloom. At final harvest (140 DAFB), fruits representing the size range within each treatment were analyzed for the effects of thinning on fruit size, weight and cortex anatomy, namely, parenchyma cell size, cell number and the proportion of cortex volume occupied by intercellular space (IS). A dissecting stereobinocular microscope fitted with a ten-by-ten reticule was used to count cells and proportion of IS in three fields in each of two cortex sectors per fruit. Cell volume in each field was derived by knowing only the grid area, a point-count for proportion of IS and a count of cell numbers within the grid. Fruit size and weight decreased as thinning was prolonged and unthinned trees had the smallest fruit. Within a thinning treatment...

SummaryThe expolinear growth model of Goudriaan and Monteith (1990) is proposed as a new model for the inherent growth pattern of fruit of apple (Malus domestica Borkh.), defined as growth pattern under apparently non–limiting conditions This function has three parameters: maximum relative growth rate, maximum absolute growth rate, and “lost time” (x intercept of the linear growth phase). Apple fruit growth (weight basis) at very low crop loads and apparently optimum environmental conditions, displays an early positive curvilinear growth followed by linear growth to harvest, and is described well by the expolinear function. The model also fits growth patterns of ‘Empire’ and ‘Golden Delicious’ apple fruit differing in the rate of growth in the exponential phase due to differences in the crop load. Estimates of cortical cell numbers in ‘Empire’ fruit from related studies suggest that during the linear phase in mid–season, different growth rates among crop load treatments were apparently controlled by diffe...

Semipermeability may be defined as the ability of seed coverings to allow water uptake and gas exchange, while solute diffusion is restricted or prevented. The presence and location of a semipermeable layer was studied in seed coats of cabbage, leek, onion, tomato, and pepper. Morphological studies did not reveal a semipermeable layer in cabbage seed coats, and all subsequent research was performed on seeds of the other four species. Electron microscopy studies revealed that the semipermeable layer is located at the innermost layer of the seed coat just next to the endosperm. Ultrastructurally, the layer was similar for the four species, typically amorphous, highly compact, but easily distinguished from the remainder of the seed coat and endosperm tissue. The layer was permeable to water while inhibiting uptake of lanthanum salts. Histochemical analysis revealed that the semipermeable layer in seed coats of leek and onion was composed primarily of cutin, while in tomato and pepper the layer was composed of suberin.

The fungus Aureobasidium pullulans is ubiquitous and can cause russet of fruit in New York orchards. The details of russet induction by this fungus are not well known. We inoculated `McIntosh' apple fruits with a suspension of A. pullulans spores (10 million colony-forming units/mL) 1–2 weeks postbloom or later at about 30 days postbloom. We dropped inoculum into plastic “microwells” attached to the fruit surface. The cuticle of uninoculated fruit (wells filled with water only) had no russet by autumn. Skin susceptibility to russet diminished with fruit age. The cuticle of inoculated young fruit began to break down in a few days, likely through direct cuticular digestion. Further erosion and breaching of the protective cuticle caused underlying epidermal cells to die. Within 1–2 weeks, cuticle disruption and epidermal cell death were widespread. This stimulated the fruit to initiate a repair process that involved periderm formation (russet), where many rows of cells were produced in nearby tissue to seal off the injury. This type of repair is not stretchable, so as young fruit expanded, additional skin splits and checks developed. This breakdown–repair process repeated itself, which created a scurfy skin. Older fruit did not expand as much after inoculation as did young fruit, and so they developed few obvious leathery patches of periderm. Older cuticle also resisted digestion better than did the young fruit cuticle, but we do not know if resistance resulted from increased cuticle thickness in older fruit or a change in cuticular compounds during fruit growth. Regardless, A. pullulans applied to older fruit did not progress beyond the early phase of cuticle digestion, even after 3 weeks postinoculation.

Grapevine yellows is a destructive, worldwide disease of grapevines that is caused by a phytoplasma, a bacterium-like organism that infects and disrupts the vascular system of shoots. The North American form of grapevine yellows (NAGY) has been observed in New York State since the mid-1970s and in Virginia since the mid-1990s. Symptoms duplicate those of vines suffering from an Australian disease complex known as Australian grapevine yellows (AGY). We sought to determine if infected `Chardonnay' vines have common anatomical characteristics across the three regions. At each geographic site in late summer, 2003–04, leaf and internode samples were taken from younger green regions of shoots and from mature basal regions in the fruiting zone. These were processed for histology. The anatomy of each organ type was compared between locations on the shoot, between geographic locations, and between affected and normal shoots. The phloem was the only tissue universally affected in vines with NAGY or AGY symptoms. In stem internodes, both primary phloem and secondary phloem showed many senescent cells, abnormally proliferated giant cells, and hyperplasia. In affected secondary phloem there was disruption of the radial files of cells that normally differentiate from the cambium into mature phloem cell types. Normal bands of secondary phloem fibers (“hard phloem”) in internodes were weak or absent in affected vines. Leaves also had disrupted phloem organization but near-normal xylem organization in vines with symptoms. Leaves of infected vines frequently showed a disruption of sugar transport out of the leaf blades, manifested by a heavy buildup of starch in chloroplasts of mesophyll cells and bundle-sheath cells.

In 2002 in New York State, we collected king fruit of `Gala' and `Red Delicious' on fruiting spurs from 0 to 66 days after full bloom (DAB). In 2003 in Washington State, we collected king fruit of these cultivars from 14 to 62 DAB. At each collection we determined radial cell number across the fruit cortex and developmental stage of the embryo and endosperm in seeds. Fruit diameter was slightly greater in Washington fruit than in New York fruit until about 40 DAB; thereafter, New York `Delicious' outgrew Washington `Delicious', while `Gala' in the two climates (and two different years) grew identically. The New York fruits had a much earlier rise in fruit growth rate and maintained a slightly higher rate throughout the period. The cortex thickness of Washington fruit was greater than that of New York fruit for both cultivars. Most rapid cell division in the cortex occurred between 10 and 28 DAB and, by 40 DAB, most cell proliferation had ceased. The Washington fruit formed more cells across the radius than did New York fruit. Cortex thickness increased with respect to increase in cortex cell number about 30% to 40% faster in Washington fruit than in New York fruit. Developmental stages of embryos and endosperm followed a sigmoid time pattern for both cultivars in both states. By 60 DAB, embryos and endosperm reached their maximum stage of development. In both cultivars and states, cell divisions were nearly completed by the time the embryo and endosperm approached stage 3: for embryos this is the heart-shaped stage, for endosperm it is near completion of cell wall formation. The completion of wall formation in the endosperm, the near completion of cortex cell division, and the generation of the cotyledons and apical meristems in the embryo are highly correlated processes. We saw no evidence that endosperm development precedes embryo development.

Northeastern U.S. grape growers have become more knowledgeable about many aspects of grape production, including pruning and training, canopy management, nutritional recommendations, pest and disease management strategies, vineyard floor management, etc. Important to all these aspects is a firm understanding of vine structure and development. Yet, there is no current publication on vine growth and development that growers and researchers can consult to gain an understanding of the organs, tissues, and developmental processes that contribute to growth and production of quality vines in the northeastern U.S. climate. A concerted effort is underway to secure enough information on how vines are constructed, grow, and develop in the northeast so that a publication useful to a wide audience can be produced. Our objective is to consolidate information already on hand that can help explain the internal and external structures of grapevines that are pertinent to the needs of northeast growers, to add information that is lacking by collecting and examining vine parts, and to work toward integrating vine structure with vine physiology and viticultural practices. Over the past decade, organs of various native American, French hybrid, and vinifera varieties have been collected from vineyards at Cornell's experiment stations and from growers' vineyards in the Finger Lakes and Lake Erie regions. Much quantitative data on vine development have been collected and interpreted. Lab work has included dissections of organs, histological and microscopic examination, microphotography, and the production of interpretive diagrams and charts. A list of the subject matter and examples of visual materials will be presented.

For 4 years, six-flowered clusters on 20, unthinned, open-pollinated `Empire'/MM106 trees were labeled at bloom and fruit drop monitored at the king (K) and lateral positions L1 (basal) to L5 (distal) (100 to 120 clusters/year). Depending on year, fruit dropped in 1, 2, or 3 major periods by 8 weeks postbloom (PB), with total percent dropped between 65% and 75%. K fruit dropped least, L4 and L5 most. Trends were that K fruit at October harvest were largest and heaviest (significantly so in some years) and L5 fruit smallest. In nine trees, hand-thinned to single-fruited spurs at 12 days PB, where the fruit at the retained position was known, there was no statistical difference in fruit weight, fruit size, or seed count between cluster positions at final harvest, although L5 fruit tended to be smallest. Numbers of spurs labeled varied from 45 to 72. Percent fruit retained at each position at October harvest was K = 89%, L1 or L2 = 87%, L3 = 83%, L4 = 83%, and L5 = 85%. Presumably, in unthinned trees the limited resources are preferentially taken by the K fruit, which especially seems to reduce set and size of its nearest lateral fruit. However, in thinned trees under lighter cropping stresses, a fruit retained at any of the positions within a cluster has a similar potential for achieving the size and weight typically seen in king fruit.

Overwintering buds and internodes of Vitis labruscana `Concord' were taken from minimal- (MP) and balance-pruned (BP) vines in Dec. 1993 and Dec. 1994 from canes whose weight, crop weight, total nodes, and nodes with periderm were known. Winter characters recorded were: node-5's primary bud basal area, total nodes, and developmental stage of cluster primordia; stage of largest cluster in the secondary bud; vascular area of cane internode 5. Fifty node-5 buds were tagged in each treatment and flower and fruit number per cluster later recorded. Regression analysis showed no effect of a shoot's crop, cane weight, node number, or nodes having periderm on any character measured in the overwintering buds or canes for either treatment. Regression analysis did show mean flower number per cluster was linearly related to mean winter stage per cluster in both treatments, with all values falling on one line. Differences between treatments were one of degree of cluster development; BP vines had more-developed winter and spring clusters and more flowers and fruit per shoot. The slope of the regression was identical the last 3 years, although the y intercept varied each year; thus, a given cluster stage in the overwintering bud was capable of producing a variable number of flowers the next season, depending on year. Flower number per shoot appeared positively related to growing-degree-days the previous season.

Winter buds of `Concord' and `Niagara' grapevines were dissected and their embryonic clusters scored to developmental stage. Stage was regressed against flower and fruit number per cluster the following year to see if flowering or fruiting potential could be gauged from bud morphology. `Concord' vines were either minimal-pruned (MP) or balance-pruned (BP) and non-irrigated or provided supplemental irrigation. `Niagara' vines were BP vines which were non-irrigated, irrigated, or nitrogen fertigated. Winter buds of MP `Concord' were significantly less developed than buds of BP vines, and flower and fruit number per cluster also significantly less. Irrigation did not affect bud construction or flower or fruit number per cluster in either pruning regime. Winter buds of `Niagara' had similar cluster stages in all treatments and there were similar flower and fruit number per cluster the following season. Within cultivar and year, there was a positive linear relationship between mean flower number or fruit number per cluster and mean stage of cluster differentiation within buds the previous dormant period. In `Concord', a given winter cluster stage allowed production of significantly more flowers and fruit in 1992 than it did in 1993. A bud's flowering potential thus varies from year to year and depends on factors not solely related to bud morphology.

Clusters of Vitis labruscana cv. Concord were grown either in full sun or canopy shade, and either not sprayed or sprayed with 3.4 Kg/Ha chlorothalonil every 2 wk from pre-bloom to veraison. Only sun-exposed, sprayed fruit produced skin russeting. Clusters of the very susceptible V. vinifera cv. Rosette were grown in direct sun, sprayed with chlorothalonil 4 times from bloom to veraison, in the presence or absence of purported anti-russeting agents. Heavy russet occurred in all treatments. Russet initiation was similar in the 2 cvs.: epidermal cells first died beneath spray residue in full sun, a phellogen then arose in the hypodermis, followed by periderm. Epidermal death began in `Rosette' within a wk of the bloom spray, but in `Concord' only after 2-3 wk post bloom and 3 sprays. `Concord' russet generally appeared as patches or scabs, whereas `Rosette' russet ranged from freckles, welts, scabs to large smooth burnished areas. In both cvs., unbroken russet consisted of uniform layers of phellum. New, deeper periderm initials arose beneath checks and cracks which formed as fruit enlarged. In `Concord', but not `Rosette', the daughter cells of each such initial were often enclosed in the original cell wall. In all cases of russet, cell walls in the periderm were suberized and sometimes lignified. Cells also contained much phenolic material.

Bud scales of terminal buds of Populus deltoides Bartr. ex Marsh. are formed by enlarged stipules. The laminae of the first bud-scale leaves mature and abscise, but the lamina of the last bud-scale leaf (or leaves) senesces prematurely and aborts. The immature lamina of the aborting leaf turns black, shrivels, and protrudes from the bud scales until physically dislodged during bud break the following spring. Senescence of the aborting bud-scale lamina begins with loss of starch and enlargement and vacuolation of cells abaxial to the dorsal bundle of the midrib at the lamina tip. These processes progress basipetally and laterally in the lamina, with degeneration becoming particularly evident in the spongy mesophyll. While lamina degeneration is under way, an abscission meristem begins to form distal to the stipules at the petiole base. Cell divisions initiating the abscission meristem are first evident in the reactivated adaxial meristem, and they spread laterally and obliquely across the petiole base. The...

Light microscopic examination of the structure of seed testa of snap and semihard bean seeds with 6% and 12% moisture contents in paraffin sections was unsuccessful because of poor paraffin infiltration and subsequent separation of subjacent and palisade cell layers. We devised an alternative method using polyethylene glycol (PEG) as the embedding material. Specimens were killed and fixed in the usual manner. They were then run up through a graded series (25, 50, 75, 100%) of PEG 1000 to PEG 1450, and finally embedded in a mixture of PEG 1450 and 4000 (19:1 by weight). Transverse and longitudinal sections retained excellent morphological detail and were suitable for histological study. Sections temporarily stained with 0.025% thionin allowed good quality photomicrographs.

Morphological and anatomical changes in shoots of vigorously growing cottonwood plants (Populus deltoides Bartr.) were studied during dormancy induction in 8-hr short days (SD) and in control plants grown in 18-hr long days (LD). Pronounced structural changes occurred in terminal buds after 4 wk and full dormancy was achieved in 7 wk of SD. Leaf expansion ceased after 5 wk of SD as foliage leaves matured to the terminal bud base at leaf plastochron index 0 (LPI 0). Within the bud, total leaf length (lamina + petiole) decreased and stipule length increased progressively each week; thus, the ratio total leaf length/stipule length decreased rapidly, especially at the position of incipient bud-scale leaves LPI -1 and LPI -2. These budscale leaves were fully developed by wk 6 and were derived from enlarged stipules and aborted laminae. The full complement of primordia within the bud at the start of SD eventually matured as foliage leaves and the first bud-scale leaf (LPI - 1) was initiated immediately following transfer to SD. Acropetal advance of the primary-secondary vascular transition zone (TZ) was associated with leaf maturation. However, it did not advance throughout the entire vascular cylinder as in LD, but only in those leaf traces serving mature leaves beneath the terminal bud. In both LD and SD treatments the same linear relationship was maintained between LPI of the TZ and LPI of the most recently matured leaf; both parameters simultaneously increased in LD and decreased in SD. Thus, the relationship between leaf maturation and advance of the TZ was maintained irrespective of environment.

Standardized raw fruits of 6 texturally different pickling cucumber (Cucumis sativus L.) genotypes and 1 parthenocarpic slicing genotype were compared for several pericarp features: total radial thickness, % of fruit radius (% pericarp), overall average parenchyma cell size and number within the pericarp radius, as well as gradient in parenchyma cell size along this radius. Texture-related rank positions were devised and assigned genotypes for each pericarp feature. These were compared to rank positions assigned these genotypes for several textural components, based on machine-measured scores. Correlation analysis showed a strong relationship between ranking genotypes for texture and ranking them for average cell number but not for texture and any of the other pericarp features. The slicing genotype deviated from the very uniform pickling genotypes in having a significantly thicker pericarp, greater % pericarp, and greater cell size across the pericarp radius.