Light quality and quantity affect graft union formation of tomato plants

AbstractIt is already known that there are many factors responsible for the successful formation of a graft union. However, the role of light has been little studied. In an anatomical study, Scanning Electronic Microscope (SEM) was used to explore the effects of different light-emitting diodes (LEDs) on graft union formation in grafted tomato. In addition, the expression genes related to Auxin hormone signaling pathway (SAUR67, AUX1, ARF30, and LAX3) was investigated. The obtained results showed that the concrescence process occurred faster under R7:B3 light conditions, as compared to blue (B) and white fluorescent (WFL) lights. Red light application caused a delay in the vascular tissue differentiation, which may lead to callus development on both sides, causing junctional failure and resulting in ineffective graft junctional arrangement. The expression of genes related to Auxin hormone significantly increased by R7:B3 application. We suggest that LED spectra affects the graft development of tomato plants and can improve the performance of grafted tomato seedlings.

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Sugars promote graft union development in the heterograft of cucumber onto pumpkin

Horticulture Research ◽

10.1038/s41438-021-00580-5 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Li Miao ◽

Qing Li ◽

Tian-shu Sun ◽

Sen Chai ◽

Changlin Wang ◽

...

Keyword(s):

Sugar Content ◽

Healing Process ◽

Energy Charge ◽

Sugar Metabolism ◽

Union Formation ◽

Graft Union ◽

Positive Role ◽

Exogenous Glucose ◽

Expression Of Genes ◽

Graft Interface

AbstractThe use of heterografts is widely applied for the production of several important commercial crops, but the molecular mechanism of graft union formation remains poorly understood. Here, cucumber grafted onto pumpkin was used to study graft union development, and genome-wide tempo-spatial gene expression at the graft interface was comprehensively investigated. Histological analysis suggested that resumption of the rootstock growth occurred after both phloem and xylem reconnection, and the scion showed evident callus production compared with the rootstock 3 days after grafting. Consistently, transcriptome data revealed specific responses between the scion and rootstock in the expression of genes related to cambium development, the cell cycle, and sugar metabolism during both vascular reconnection and healing, indicating distinct mechanisms. Additionally, lower levels of sugars and significantly changed sugar enzyme activities at the graft junction were observed during vascular reconnection. Next, we found that the healing process of grafted etiolated seedlings was significantly delayed, and graft success, xylem reconnection, and the growth of grafted plants were enhanced by exogenous glucose. This demonstrates that graft union formation requires the correct sugar content. Furthermore, we also found that graft union formation was delayed with a lower energy charge by the target of rapamycin (TOR) inhibitor AZD-8055, and xylem reconnection and the growth of grafted plants were enhanced under AZD-8055 with exogenous glucose treatment. Taken together, our results reveal that sugars play a positive role in graft union formation by promoting the growth of cucumber/pumpkin and provide useful information for understanding graft union healing and the application of heterografting in the future.

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Molecular and physiological characterization of the effects of auxin-enriched rootstock on grafting

Horticulture Research ◽

10.1038/s41438-021-00509-y ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Longmei Zhai ◽

Xiaomin Wang ◽

Dan Tang ◽

Qi Qi ◽

Huseyin Yer ◽

...

Keyword(s):

Callus Formation ◽

Ethylene Biosynthesis ◽

Union Formation ◽

Biosynthetic Gene ◽

Graft Union ◽

Specific Expression ◽

Physiological Characterization ◽

Graft Healing ◽

Expression Of Genes ◽

Or Gene

AbstractsGrafting is a highly useful technique, and its success largely depends on graft union formation. In this study, we found that root-specific expression of the auxin biosynthetic gene iaaM in tobacco, when used as rootstock, resulted in more rapid callus formation and faster graft healing. However, overexpression of the auxin-inactivating iaaL gene in rootstocks delayed graft healing. We observed increased endogenous auxin levels and auxin-responsive DR5::GUS expression in scions of WT/iaaM grafts compared with those found in WT/WT grafts, which suggested that auxin is transported upward from rootstock to scion tissues. A transcriptome analysis showed that auxin enhanced graft union formation through increases in the expression of genes involved in graft healing in both rootstock and scion tissues. We also observed that the ethylene biosynthetic gene ACS1 and the ethylene-responsive gene ERF5 were upregulated in both scions and rootstocks of the WT/iaaM grafts. Furthermore, exogenous applications of the ethylene precursor ACC to the junction of WT/WT grafts promoted graft union formation, whereas application of the ethylene biosynthesis inhibitor AVG delayed graft healing in WT/WT grafts, and the observed delay was less pronounced in the WT/iaaM grafts. These results demonstrated that elevated auxin levels in the iaaM rootstock in combination with the increased auxin levels in scions caused by upward transport/diffusion enhanced graft union formation and that ethylene was partially responsible for the effects of auxin on grafting. Our findings showed that grafting success can be enhanced by increasing the auxin levels in rootstocks using transgenic or gene-editing techniques.

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The Role of Leaves in Photocontrol of Flower Bud Abscission in Hibiscus rosa-sinensis L. `Nairobi'

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.125.1.31 ◽

2000 ◽

Vol 125 (1) ◽

pp. 31-35 ◽

Cited By ~ 2

Author(s):

Uulke van Meeteren ◽

Annie van Gelder

Keyword(s):

Light Quality ◽

Light Exposure ◽

Red Light ◽

Light Conditions ◽

Flower Bud ◽

Light Emitting ◽

Hibiscus Rosa Sinensis ◽

Number Of Leaves ◽

Whole Plants

When compared with exposure to darkness, exposing Hibiscus rosa-sinensis L. `Nairobi' plants to red light (635 to 685 nm, 2.9 μmol·m-2·s-1) delayed flower bud abscission, while exposure to far-red light (705 to 755 nm, 1.7 μmol·m-2·s-1) accelerated this process. Flower bud abscission in response to light quality appears to be controlled partly by the presence of leaves. The delay of bud abscission was positively correlated to the number of leaves being exposed to red light. Excluding the flower buds from exposure to red or far-red light, while exposing the remaining parts of the plants to these light conditions, did not influence the effects of the light exposure on bud abscission. Exposing only the buds to red light by the use of red light-emitting diodes (0.8 μmol·m-2·s-1) did not prevent dark-induced flower bud abscission. Exposing the whole plants, darkness or far-red light could only induce flower bud abscission when leaves were present; bud abscission was totally absent when all leaves were removed. To prevent flower bud abscission, leaves had to be removed before, or at the start of, the far-red light treatment. These results suggest that in darkness or far-red light, a flower bud abscission-promoting signal from the leaves may be involved.

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The Role of Bismuth on the Best Red Light Emitting Nanophosphors

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.f5362.039621 ◽

2021 ◽

Vol 9 (6) ◽

pp. 55-59

Author(s):

Vini. K ◽

Padmakumar H. ◽

K.M. Nissamudeen

Keyword(s):

Rare Earths ◽

Light Emitting Diodes ◽

Red Light ◽

Combustion Method ◽

Processing Temperature ◽

X Ray Diffraction ◽

Luminescence Enhancement ◽

Light Emitting ◽

X Ray

This paper explains the role of bismuth in the luminescence enhancement of Y2O3 :Eu nanophosphors prepared by Combustion method. Bi ions serve as effective sensitizers for visible emitting rare earths for Light Emitting Diodes. From the X-ray diffraction studies, bismuth co-activated nanophosphors exhibit an early crystallization. Bismuth incorporation not only results in the luminescence enhancement at 612 nm, due to 5D0 to 7F2 transition but also reduces the processing temperature for intense photoemission.

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Stomatal opening and growth in tomato seedlings treated with different proportions of red and blue light

Canadian Journal of Plant Science ◽

10.1139/cjps-2018-0241 ◽

2019 ◽

Vol 99 (5) ◽

pp. 688-700 ◽

Cited By ~ 2

Author(s):

Junwei Yang ◽

Tingting Liang ◽

Lu Liu ◽

Tonghua Pan ◽

Zhirong Zou

Keyword(s):

Blue Light ◽

Light Quality ◽

Red Light ◽

Chloroplast Ultrastructure ◽

Net Photosynthesis ◽

Dry Weight ◽

Stomatal Opening ◽

Detailed Knowledge ◽

Tomato Seedlings

Stomatal opening/closure plays a key role in balancing a plant’s need to conserve water, while still allowing for the exchange of photosynthetic and respiratory gasses with the atmosphere. Stomatal opening/closure can be induced by differences in light quality but a detailed knowledge of the role of light in stomatal regulation in tomato is limited. In this study, we evaluated red and blue light-dependent stomatal opening processes in tomato seedlings and explored the mechanisms involved using different light-quality treatments. After 10 h of darkness, tomato seedlings were subjected to the following five treatments: monochromatic red light (R), 33% blue (2R1B), 50% blue (1R1B), 67% blue (1R2B), and monochromatic blue light (B) at 200 μmol m−2s−1light intensity. The highest stomatal conductance recorded were for 1R1B. Stomatal aperture under 1R1B showed a 92.8% increase after 15 min and a 28.6% increase after 30 min compared with under R alone. Meanwhile, the study shows that the expressions of the plasma membrane H+-ATPase in the leaf were regulated by different proportions of blue light. The results show that the expressions of HA1 and HA4 increased under 1R1B and 1R2B after 15 min of exposure compared with under R alone. Under 1R1B, our results also show net photosynthesis increased compared with R and B after longer treatments, which may be related to chloroplast ultrastructure, and leaf dry weight increased compared with under 1R2B or B alone, but there were no differences under the R and 2R1B light treatments.

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Green and Red Light Reduces the Disease Severity by Pseudomonas cichorii JBC1 in Tomato Plants via Upregulation of Defense-Related Gene Expression

Phytopathology ◽

10.1094/phyto-04-14-0108-r ◽

2015 ◽

Vol 105 (4) ◽

pp. 412-418 ◽

Cited By ~ 20

Author(s):

Rajalingam Nagendran ◽

Yong Hoon Lee

Keyword(s):

Disease Severity ◽

White Light ◽

Disease Incidence ◽

Red Light ◽

Light Conditions ◽

Pseudomonas Cichorii ◽

Tomato Plants ◽

Tomato Seedlings ◽

Pathogenesis Related Protein ◽

Dark Conditions

Light influences many physiological processes in most organisms. To investigate the influence of light on plant and pathogen interaction, we challenged tomato seedlings with Pseudomonas cichorii JBC1 by flood inoculation and incubated the seedlings under different light conditions. Tomato seedlings exposed to green or red light showed a significant reduction in disease incidence compared with those grown under white light or dark conditions. To understand the underlying mechanisms, we investigated the effects of each light wavelength on P. cichorii JBC1 and tomato plants. Treatment with various light wavelengths at 120 µmol m–2s–1 revealed no significant difference in growth, swarming motility, or biofilm formation of the pathogen. In addition, when we vacuum-infiltrated P. cichorii JBC1 into tomato plants, green and red light also suppressed disease incidence which indicated that the reduced disease severity was not from direct influence of light on the pathogen. Significant upregulation of the defense-related genes, phenylalanine ammonia-lyase (PAL) and pathogenesis-related protein 1a (PR-1a) was observed in P. cichorii JBC1-infected tomato seedlings grown under green or red light compared with seedlings grown under white light or dark conditions. The results of this study indicate that light conditions can influence plant defense mechanisms. In particular, green and red light increase the resistance of tomato plants to infection by P. cichorii.

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Physiological, Nutritional and Metabolomic Responses of Tomato Plants After the Foliar Application of Amino Acids Aspartic Acid, Glutamic Acid and Alanine

Frontiers in Plant Science ◽

10.3389/fpls.2020.581234 ◽

2021 ◽

Vol 11 ◽

Author(s):

Marina Alfosea-Simón ◽

Silvia Simón-Grao ◽

Ernesto Alejandro Zavala-Gonzalez ◽

Jose Maria Cámara-Zapata ◽

Inmaculada Simón ◽

...

Keyword(s):

Climate Change ◽

Amino Acids ◽

Amino Acid ◽

Glutamic Acid ◽

Aspartic Acid ◽

Foliar Application ◽

Pentose Phosphate ◽

Tomato Plants ◽

Tomato Seedlings

Agriculture is facing a great number of different pressures due to the increase in population and the greater amount of food it demands, the environmental impact due to the excessive use of conventional fertilizers, and climate change, which subjects the crops to extreme environmental conditions. One of the solutions to these problems could be the use of biostimulant products that are rich in amino acids (AAs), which substitute and/or complement conventional fertilizers and help plants adapt to climate change. To formulate these products, it is first necessary to understand the role of the application of AAs (individually or as a mixture) in the physiological and metabolic processes of crops. For this, research was conducted to assess the effects of the application of different amino acids (Aspartic acid (Asp), Glutamic acid (Glu), L-Alanine (Ala) and their mixtures Asp + Glu and Asp + Glu + Ala on tomato seedlings (Solanum lycopersicum L.). To understand the effect of these treatments, morphological, physiological, ionomic and metabolomic studies were performed. The results showed that the application of Asp + Glu increased the growth of the plants, while those plants that received Ala had a decreased dry biomass of the shoots. The greatest increase in the growth of the plants with Asp + Glu was related with the increase in the net CO2 assimilation, the increase of proline, isoleucine and glucose with respect to the rest of the treatments. These data allow us to conclude that there is a synergistic effect between Aspartic acid and Glutamic acid, and the amino acid Alanine produces phytotoxicity when applied at 15 mM. The application of this amino acid altered the synthesis of proline and the pentose-phosphate route, and increased GABA and trigonelline.

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