Disentangling The Link Between Leaf Photosynthesis And Turgor On Fruit Growth

NAA is used extensively for fruit thinning of apples to increase fruit size and to promote return bloom. In some cultivars, even if thinning is achieved, fruit size at harvest may be less than expected based on crop load. CPPU, N-(2-chloro-4-pyridinyl)-N.-phenylurea, has been shown to increase fruit growth in apples, grapes, and kiwi. We evaluated combinations of NAA and CPPU on thinning, fruit growth and return bloom in Redchief `Delicious', `Elstar', and `Gloster'. CPPU was applied at 5 mgμL–1 (based on 0 to 10 mgμL–1 response curve) in combination with 15 mgμL–1 NAA as high-volume sprays at 7 to 10 mm KFD. Yield and fruit size distribution (on total yield) were used as index of response. In `Delicious', CPPU (3-year study) increased % large (70 mm+) fruit, but in the presence of NAA % large fruit was reduced 2 of the 3 years. CPPU did not induce significant thinning. There were no significant effects on color or soluble solids; firmness was increased slightly and seed number reduced. The L/D ratio was increased and uneven lobe and carpel development was common. CPPU had no significant effect on return bloom in presence or absence of NAA, but NAA increased bloom in both the presence and absence of CPPU. With `Elstar' (2-year study) there was no significant thinning with either chemical, but CPPU increased mean fruit size and % large (70–80 mm) fruit over nonthinned, but not significantly greater than NAA alone. There were no significant differences in firmness, color, soluble solids or seed number. NAA + CPPU did not inhibit fruit growth or cause excessive uneven carpel development. Frost damage reduced crop load in `Gloster' where results were similar to `Elstar' except seed number was reduced by the NAA + CPPU combination.

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Scaling leaf photosynthesis to canopy in a mixed deciduous forest. I. model description

Silva Gandavensis ◽

10.21825/sg.v62i0.842 ◽

1997 ◽

Vol 62 ◽

Author(s):

R. Samson ◽

S. Follens ◽

R. Lemeur

Keyword(s):

Temperature Dependence ◽

Quercus Robur ◽

Deciduous Forest ◽

Growing Season ◽

Model Description ◽

Canopy Photosynthesis ◽

Leaf Photosynthesis ◽

Layer Model ◽

Mixed Deciduous Forest ◽

Leaf Level

A multi-layer model (FORUG) was developed, to simulate the canopy photosynthesis of a mixed deciduous forest during the growing season. Measured photosynthesis parameters, for beech (Fagus sylvatica), oak (Quercus robur) and ash (Fraxinus excelsior), were used as input to the model. This information at the leaf level is then scaled up to the level of the canopy, taking into account the radiation profiles (diffuse and direct PAR) in the canopy, the vertical LAI distribution, the evolution of the LAI and the photosynthesis parameters during the growing season, and the temperature dependence of the latter parameters.

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Pollen grain hormones of date palm pollinator cultivars and their relationship with hormones of different stages of ‘Piarom’ date fruit growth

Scientia Horticulturae ◽

10.1016/j.scienta.2021.110389 ◽

2021 ◽

Vol 288 ◽

pp. 110389

Author(s):

Ali Reza Shahsavar ◽

Asma Shahhosseini

Keyword(s):

Date Palm ◽

Pollen Grain ◽

Fruit Growth ◽

Date Fruit

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Is There Daily Growth Hysteresis versus Vapor Pressure Deficit in Cherry Fruit?

Horticulturae ◽

10.3390/horticulturae7060131 ◽

2021 ◽

Vol 7 (6) ◽

pp. 131

Author(s):

Matteo Zucchini ◽

Arash Khosravi ◽

Veronica Giorgi ◽

Adriano Mancini ◽

Davide Neri

Keyword(s):

Vapor Pressure ◽

Vapor Pressure Deficit ◽

Fruit Growth ◽

Hysteresis Curve ◽

Growth Stages ◽

Fourth Stage ◽

The Third ◽

Third Stage ◽

Rainy Days ◽

Clockwise Hysteresis

The growth of cherry fruit is generally described using a double sigmoid model, divided into four growth stages. Abiotic factors are considered to be significant components in modifying fruit growth, and among these, the vapor pressure deficit (VPD) is deemed the most effective. In this study, we investigated sweet cherry fruit growth through the continuous, hourly monitoring of fruit transversal diameter over two consecutive years (2019 and 2020), from the beginning of the third stage to maturation (forth stage). Extensometers were used in the field and VPD was calculated from weather data. The fruit growth pattern up to the end of the third stage demonstrated three critical steps during non-rainy days: shrinkage, stabilization and expansion. In the third stage of fruit growth, a partial clockwise hysteresis curve of circadian growth, as a response to VPD, appeared on random days. The pattern of fruit growth during rainy days was not distinctive, but the amount and duration of rain caused a consequent decrease in the VPD and indirectly boosted fruit growth. At the beginning of the fourth stage, the circadian growth changed and the daily transversal diameter vs VPD formed fully clockwise hysteresis curves for most of this stage. Our findings indicate that hysteresis can be employed to evaluate the initial phenological phase of fruit maturation, as a fully clockwise hysteresis curve was observable only in the fourth stage of fruit growth. There are additional opportunities for its use in the management of fruit production, such as in precision fruit farming.

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