Environmental Effects on Dynamics of Fruit Growth and Photoassimilate Translocation in Tomato Plants. (2). Analysis of Phloem Sap and Xylem Sap Fluxes and Fruit Water Balance.

Nutrient consumption by plants depends on the growth stage and environmental conditions. In general, plants take up species of elements at different speeds. We monitored and recorded the electrical charge flow through xylem sap of tomato plants (Brillante F1) using femto/picoammeter equipment (Keysight B2981A). This technique evaluates the nutrient uptake of tomato treated with the most common macronutrients (KNO3; KH2PO4; Ca(NO3)2; KCl) by monitoring the electrical conductivity for 24 h. The electrical conductivity of each treatment correlated with the plant growth and development stages. The results showed that the tomato plants had a high consumption of nutrients in the vegetative stage, while in other stages, they had a specific consumption, like phosphorus for bulb formation, potassium for increasing the number of flowers and water for the ripening of fruits. The quantitative evaluation of the ions absorbed by the plant was based on the magnitude and shape of the electrical conductivity curves. Our technique is an efficient method to determine nutrient consumption and is useful in predicting the deficiency of a certain element in tomato plants.

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Trehalose induces tomato defenses and increases drought tolerance and bacterial wilt disease resistance

10.1101/2021.07.26.453814 ◽

2021 ◽

Author(s):

April M MacIntyre ◽

Valerian Meline ◽

Zachary Gorman ◽

Steven P Augustine ◽

Carolyn J Dye ◽

...

Keyword(s):

Disease Resistance ◽

Stomatal Conductance ◽

Water Use ◽

Bacterial Wilt ◽

Xylem Sap ◽

Wilt Disease ◽

Tomato Plants ◽

Bacterial Wilt Disease ◽

Infected Tomato ◽

Use Efficiency

Ralstonia solanacearum causes plant bacterial wilt disease, leading to severe crop losses. Xylem sap from R. solanacearum-infected tomato is enriched in host produced trehalose. Water stressed plants accumulate the disaccharide trehalose, which increases drought tolerance via abscisic acid (ABA) signaling networks. Because infected plants have reduced water flow, we hypothesized that bacterial wilt physiologically mimics drought stress, which trehalose could mitigate. Transcriptomic responses of susceptible vs. resistant tomato plants to R. solanacearum infection revealed differential expression of drought-associated genes, including those involved in ABA and trehalose metabolism. ABA was enriched in xylem sap from R. solanacearum-infected plants. Treating roots with ABA lowered stomatal conductance and reduced R. solanacearum stem colonization. Treating roots with trehalose increased ABA in xylem sap and reduced plant water use by reducing stomatal conductance and temporarily improving water use efficiency. Further, trehalose-treated plants were more resistant to bacterial wilt disease. Trehalose treatment also upregulated expression of salicylic acid (SA)-dependent defense genes, increased xylem sap levels of SA and other antimicrobial compounds, and increased wilt resistance of SA-insensitive NahG tomato plants. Additionally, trehalose treatment increased xylem concentrations of jasmonic acid and related oxylipins. Together, these data show that exogenous trehalose reduced both water stress and bacterial wilt disease and triggered systemic resistance. This suite of responses revealed unexpected linkages between plant responses to biotic and abiotic stress and suggests that that R. solanacearum-infected tomato plants produce more trehalose to improve water use efficiency and increase wilt disease resistance. In turn, R. solanacearum degrades trehalose as a counter-defense.

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Patterns of photoassimilate translocation between shoots in Chinese chestnut trees during flowering and fruit growth

Australian Forestry ◽

10.1080/00049158.2015.1043697 ◽

2015 ◽

Vol 78 (2) ◽

pp. 86-91 ◽

Cited By ~ 1

Author(s):

Peng Xie ◽

Sujuan Guo

Keyword(s):

Fruit Growth ◽

Chinese Chestnut ◽

Photoassimilate Translocation

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Changes in phytohormone levels following inoculation of two soybean lines differing in nodulation

Functional Plant Biology ◽

10.1071/pp01166 ◽

2002 ◽

Vol 29 (8) ◽

pp. 965 ◽

Cited By ~ 14

Author(s):

Asghari Bano ◽

James E. Harper ◽

Robert M. Auge ◽

Dawn S. Neuman

Keyword(s):

Glycine Max ◽

Xylem Sap ◽

Zeatin Riboside ◽

Phloem Sap ◽

Root Nodulation ◽

Hormone Transport ◽

Glycine Max L ◽

Bradyrhizobium Inoculation

Changes in the concentration of free and conjugated ABA, zeatin riboside (ZR), and IAA in response to Bradyrhizobium inoculation and subsequent nodulation were monitored in xylem sap, phloem sap, and leaves of soybean [Glycine max (L.) Merr. cv. Williams 82] and its hypernodulating mutant, NOD1-3. In this study, pre-inoculation concentrations of phloem and xylem sap ABA and ZR were lower in NOD1-3 than in Williams 82, a difference that was accentuated in phloem after inoculation. The concentration of xylem ABA increased within 6�h of inoculation, while the concentration of phloem and leaf ABA did not change until 48-96 h after inoculation. Leaf uptake of [3H]ABA and distribution to phloem sap was greater in Williams 82 than in NOD1-3 during 48-72�h after inoculation. Inoculation resulted in similar increases in phloem and leaf IAA concentrations in both cultivars. While inoculation increased xylem sap ZR in both lines, the concentration of ZR increased much earlier in NOD1-3. Of particular interest is that ratios between hormones were altered during nodulation. Leaf and phloem ABA/IAA ratios were higher in Williams 82 than in the hypernod mutant, while the phloem IAA/ZR was greater from inoculation until nodulation in the NOD1-3 hypernod mutant. The xylem ABA/ZR ratio, as well as phloem ABA/ZR ratio, decreased in Williams 82 following inoculation, and leaf ABA concentration was elevated. The most noteworthy results of this study, therefore, came from an examination of the ratios between hormones in xylem and phloem sap, and the demonstration that hormone transport may play an important role in autoregulation of root nodulation.

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DYNAMICS OF FRUIT GROWTH AND WATER RELATIONS IN TOMATO PLANTS (LYCOPERSICON ESCULENTUM MILL.) AS AFFECTED BY ROOT WATER CONDITION

Acta Horticulturae ◽

10.17660/actahortic.1996.440.37 ◽

1996 ◽

pp. 211-216

Author(s):

M. Kitano ◽

H. Eguchi

Keyword(s):

Lycopersicon Esculentum ◽

Water Relations ◽

Fruit Growth ◽

Tomato Plants ◽

Water Condition ◽

Lycopersicon Esculentum Mill

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Nitrate Transport Rate in the Xylem of Tomato Plants Grafted onto a Vigorous Rootstock

Agronomy ◽

10.3390/agronomy10020182 ◽

2020 ◽

Vol 10 (2) ◽

pp. 182 ◽

Cited By ~ 2

Author(s):

Francisco Albornoz ◽

Alonso G. Pérez-Donoso ◽

Jorge Leigh Urbina ◽

Matías Monasterio ◽

Miguel Gómez ◽

...

Keyword(s):

Water Uptake ◽

N Uptake ◽

Xylem Sap ◽

Light Level ◽

Hydraulic Conductance ◽

Transport Rate ◽

Nitrate Transport ◽

Limited Information ◽

Cross Sectional ◽

Tomato Plants

Vigorous interspecific rootstocks increase nitrogen (N) uptake in tomato plants but limited information is available on xylem transport rate. Non-grafted and self-grafted tomato plants cv. Attiya and plants grafted onto an interspecific hybrid, Kaiser, were grown under growth chamber conditions and subjected to two light levels, 400 or 800 µmol PAR m−2 s−1. Plant water uptake, xylem sap NO3− content, and stem hydraulic conductance (ks) were measured after two weeks of growth. Xylem vessel number and diameter were evaluated in cross-sectional stem cuts and the theoretical xylem hydraulic conductance (kh) was calculated. Only the light level modified the xylem NO3− content. Grafting reduced ks by 84% in comparison to non-grafted plants. The water uptake rate and xylem sap NO3− content were 4.02 ± 0.66 g H2O kg−1 DW h−1 and 12.78 ± 1.16 mM, respectively, across all grafting treatments. The rootstock has a higher kh because the vessel diameter is 79.3 ± 14.4 µm while in non-grafted plants it is 62.0 ± 10.1 µm. Nitrate concentration and transport rate changes accordingly to the plant’s growth rate. The vigorous rootstock relies on larger vessels to supply the required amounts of N.

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083 FRUIT HYDRAULIC BUDGETS IN FRENCH PRUNE (PRUNUS DOMESTICA L. CV. FRENCH) AND THEIR EFFECTS ON FRUIT GROWTH AND CRACKING

HortScience ◽

10.21273/hortsci.29.5.440a ◽

1994 ◽

Vol 29 (5) ◽

pp. 440a-440

Author(s):

Rémy E Milad ◽

Kenneth A Shackel

Keyword(s):

Fruit Growth ◽

Gradual Decrease ◽

Primary Role ◽

Prunus Domestica ◽

Phloem Sap ◽

Highly Correlated

End cracking of French prune fruits occurs when previously water stressed trees are irrigated during early July. Fruit phloem, xylem and transpiration flows (P, X and T, respectively) were measured diurnally during 72 h periods in mid June, early July and mid July (before, during and after the crack-susceptible period). Midway through each 72 h period, the previously stressed trees were irrigated. In mid June, X was larger than P, whereas P was larger than X during early July. In mid July, P and X were similar. In early July, the period preceding irrigation was characterized by an ourflow of phloem sap during the day and phloem inflow during the night. After irrigation, larger phloem inflows were observed and no phloem outflow occurred. Fruit transpiration rates were highly correlated with VPD. They exhibited a gradual decrease during the season, reaching minimum values during early July, before increasing again. The sum of P and X was virtually identical for the three periods i.e. stronger P's compensated for weaker X's and vice versa. Our results suggest that properties intrinsic to the fruit play the primary role in modulating water and photosynthate movements between the tree and the fruit. The possible role of these properties on fruit growth and cracking will be examined.

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