Carl Bogdanoff

How distinct are arbuscular mycorrhizal fungal communities associating with grapevines

Grapevines form associations with arbuscular mycorrhizal (AM) fungi. These root-dwelling fungi have the potential to contribute to crop vigor, productivity, pathogen protection, and nutrient content in grapes. In this study the arbuscular mycorrhizal fungal communities of grapevines and the surrounding interrow and native vegetation are compared. We found over 40 different taxa associating with both vines and interrow vegetation, but these communities differed based on host plant identity. These differences were apparent even after accounting for differences in soil chemical properties and differences in host plant diversity between vinerows and interrows, indicating that Vitis preferentially interacts with a subset of the viticultural fungal community. Since AM fungal communities play a major role in grapevine health, our results suggest that host identity and the diversity of AM fungal hosts in a vineyard can have strong effects on arbuscular mycorrhizal fungi community structure. In this paper, we used high throughput sequencing of the large subunit rDNA to analyze the diversity of AM fungi growing in a vineyard.

Effects of Irrigation and Crop Load on Leaf Gas Exchange and Fruit Composition in Red Winegrapes Grown on a Loamy Sand

Effects of reducing irrigation from fruit set to veraison or harvest combined with crop-load adjustment by cluster or shoot thinning were determined for Merlot and Cabernet Sauvignon grapevines cultured on a coarse loamy sand. Geographic information system tools were used to develop maps of moisture distribution in the soil profile, which revealed reductions in total moisture levels and increased spatial variation in response to reduced emitter density. Stomatal conductance and leaf gas exchange decreased in response to reduced irrigation but also declined across all treatments during the lag phase of berry development and then increased postveraison. Pruning mass was affected little by treatments in Merlot but was reduced by either shoot or cluster thinning in Cabernet Sauvignon. Berry mass and anthocyanin and tannin contents were affected little and inconsistently by irrigation and crop-load adjustment and varied mostly among years, indicating a dominant influence of seasonal climate on berry development and composition.

Impacts of using polyethylene sleeves and wavelength-selective mulch in vineyards. II. Effects on growth, leaf gas exchange, yield components and fruit quality of Vitis vinifera cv. Merlot

Response of Merlot vines to wavelength-selective polyethylene mulch in the planted row and clear polyethylene enclosures (sleeves) around canes or cordons for 7 wk in the spring was studied in three Okanagan Valley vineyards. The mulch had no detectable effects on vine development, yield components and fruit quality. The sleeves advanced budbreak by 3 to 6 d, depending on the vineyard site, and increased the early growth rate of shoots. Time of budbreak and shoot growth rate were better predicted by cumulative daily mean temperature than by cumulative degree days (base 10°C). On the day sleeves were removed or opened at top, photosynthesis rates were higher in open-top sleeves than under ambient conditions due to higher mesophyll and stomatal conductances. Sleeves advanced the date of 50% bloom in all vineyards by approximately 10 d. Time of bloom, onset of veraison and the rate of fruit maturation were predictable from degree day accumulation. Sleeves advanced fruit maturation by 7 to 26 d, depending on ...

Impacts of using polyethylene sleeves and wavelength-selective mulch in vineyards. I. Effects on air and soil temperatures and degree day accumulation

Effects on soil and air temperatures of wavelength-selective polyethylene mulch applied in planted rows, and clear polyethylene enclosures (sleeves) applied around vine canes or cordons for 7 wk in the spring were determined in three Merlot vineyards in the Okanagan Valley, British Columbia. Three sleeve configurations were studied: single-layer and closed at bottom; single-layer with bottom ventilation added after 5 wk; and double-layer with bottom ventilation added after 5 wk. All sleeves were perforated at the top between two supporting trellis catch wires, and were stapled closed at the bottom under the cordon or cane. Sleeve removal was either all at once or in two stages by first opening the top then removing the sides 6 d later. The sleeves increased mean air temperatures by ca. 1 to 2°C and maximum temperatures by ca. 5 to 8°C, and decreased minimum temperatures by ca. 1 to 2 °C, depending on the vineyard, measurement period, and sleeve configuration. Adding bottom ventilation to sleeves increased...

Effects of Converting from Sprinkler to Drip Irrigation on Water Conservation and the Performance of Merlot Grown on a Loamy Sand

Effects of converting from overhead sprinkler to drip irrigation on the growth, leaf gas exchange, and fruit production of Merlot grapevines with and without cluster thinning were determined over four years. Drip or sprinkler irrigation was applied to the loamy sand soil when in-row soil moisture was depleted to <8%. Irrigation frequency averaged 50% higher (27 compared with 18 times per year) under drip than sprinkler irrigation, but 64% less water (574 compared with 1580 L per vine per yr) was applied on average under drip. Maps of moisture in the soil profile revealed differences in moisture distribution and dry-down dynamics in response to irrigation method. Increasing soil dry-down rates over years indicated that roots proliferated within the drip-irrigated soil volume. Converting to drip reduced the growth and survival of floor vegetation. Vine vigor, leaf gas exchange, and crop yield were reduced but crop yield recovered in the second year and vigor recovered by the fourth year. Stomatal conductance and leaf gas exchange remained lower under drip irrigation. Transpirational water-use efficiency was higher under drip than sprinkler irrigation in the first three years. Input water use efficiency averaged 2.5 times higher under drip irrigation over the four years. Fruit maturation was advanced by drip compared with sprinkler irrigation each year and was associated with increased cluster exposure and higher ambient temperatures. Cluster thinning also advanced fruit maturation but reduced crop yield substantially each year and had only minor interactions with irrigation method.

Arbuscular Mycorrhizal Fungal Communities Associated with Vitis vinifera Vines under Different Frequencies of Irrigation

The effects of irrigating daily or every three days on arbuscular mycorrhizal fungal communities associated with grapevine roots were determined in vineyard blocks of Merlot and Syrah on 3309 rootstock. After exposure to treatments for four growing seasons, root samples were analyzed for changes in AM fungal colonization, species richness, and community composition. AM fungal colonization was higher in response to irrigating every three days compared with daily irrigation, indicating a treatment effect on the physiology of the fungal communities. Using a pyrosequencing approach, no difference in AM fungal community composition was found in response to irrigation frequency. Species richness, identity and dispersion were consistent across the two treatments. A difference in AM fungal communities between the two varietal blocks was associated with differences in soil chemistry and plant physiological traits. In particular, soil carbon and extractable copper levels along with vine vigor and photosynthesis were correlated with community variation. This indicates environmental factors other than irrigation frequency influence the fungal community structure in vineyards.

Response of Grapevine Rootstocks to Soil Inocula from Different Sources

Although arbuscular mycorrhizal (AM) fungal inoculants are widely used as bioinoculants in plant nurseries, it is not clear whether this practice is beneficial for grapevine rootstocks. Here, a greenhouse study was conducted to compare the effects of locally sourced soil microbial inocula with two commercial mycorrhizal inocula on root colonization and early growth and physiology of grapevine rootstocks Riparia Gloire, 101–14 Mgt and SO4. Mycorrhizal colonization varied widely; the greatest colonization (63%) occurred with a commercial inoculum, followed by a local inoculum composed of native-plant root fragments (19%). The other inocula produced poor or no colonization. Colonization by a commercial and a local inoculum increased leaf greenness in SO4 vines. Greater root and shoot biomass and shoot length were observed in Riparia Gloire and 101-14 Mgt vines treated with local inocula compared to commercial inocula. The inconsistent effects among rootstocks and inocula indicate that the effectiveness of mycorrhizal inocula for enhancing plant growth is unpredictable.

A study on the interplay between energy and matter transformation: the effect of elevated temperatures on the leaf morphology of Vitis vinifera var. Merlot

This investigation explores the relationship between increased energy levels and leaf morphology. It tests the idea that the causal agent of development is the dissipation of energy into transformed matter. The energy under which leaves developed was modified by increasing temperatures in grape cordons through wrapping them in clear plastic sleeves in the early spring. At the higher temperatures, and energy levels, there was a small but statistically significant decrease in leaf size and a change in organization the leaves. The decrease in leaf size may be due to a reallocation of resources, either to greater shoot growth as a previous study demonstrated or to the appearance of more vectors of development in the leaves, i.e. the appearance of more developmental subsystems. The leaves that grew under the higher temperature regime were more complex, perhaps indicating that the grapes on those same vines may produce more complex juice, another expression of more developmental subsystems. The change in organization in these leaves that developed at higher temperature argues that the causal agent in plant development is energy dissipation and the concomitant transformation of matter, the latter expressed in the appearance of more growth vectors.