root elongation
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2022 ◽  
Vol 296 ◽  
pp. 118784
Author(s):  
Yang Yang ◽  
Yemian Peng ◽  
Yibing Ma ◽  
Guojun Chen ◽  
Fangbai Li ◽  
...  

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaoning Gao ◽  
Jinsong Dong ◽  
Fatemeh Rasouli ◽  
Ali Kiani Pouya ◽  
Ayesha T. Tahir ◽  
...  

Abstract Background Chilling temperature reduces the rate of photosynthesis in plants, which is more pronounced in association with phosphate (Pi) starvation. Previous studies showed that Pi resupply improves recovery of the rate of photosynthesis in plants much better under combination of dual stresses than in non-chilled samples. However, the underlying mechanism remains poorly understood. Results In this study, RNA-seq analysis showed the expression level of 41 photosynthetic genes in plant roots increased under phosphate starvation associated with 4 °C (-P 4 °C) compared to -P 23 °C. Moreover, iron uptake increased significantly in the stem cell niche (SCN) of wild type (WT) roots in -P 4 °C. In contrast, lower iron concentrations were found in SCN of aluminum activated malate transporter 1 (almt1) and its transcription factor, sensitive to protein rhizotoxicity 1 (stop1) mutants under -P 4 °C. The Fe content examined by ICP-MS analysis in -P 4 °C treated almt1 was 98.5 ng/µg, which was only 17% of that of seedlings grown under -P 23 °C. Average plastid number in almt1 root cells under -P 4 °C was less than -P 23 °C. Furthermore, stop1 and almt1 single mutants both exhibited increased primary root elongation than WT under combined stresses. In addition, dark treatment blocked the root elongation phenotype of stop1 and almt1. Conclusions Induction of photosynthetic gene expression and increased iron accumulation in roots is required for plant adjustment to chilling in association with phosphate starvation.


2021 ◽  
Author(s):  
◽  
Nurul Akmar Binti Che Zaudin

<p>Efficient and effective delivery of fertilisers, herbicides, pesticides and growth regulating compounds to plants is the subject of much ongoing research. The objective of this research was to develop nano-formulations for delivery of compounds to plants. Two formulations were developed: the first was solution-based focused on encapsulation of the active ingredient in a nanoemulsion. Nanoemulsions should be ideal for facilitating transfer of compounds to plant leaves as their size correlates well with the nanoscale surface features of leaves, achieving significantly greater total contact area between the oil droplets and the leaves. The second nano-formulation was solid-state based, focused on locating the active ingredient within the tubules of a nanotube clay.  For proof-of-concept two synthetic plant hormones, N-phenyl-N‘-(2-chloro-4-pyridyl)urea (CPPU) or forchlorfenuron, a synthetic cytokinin, and 2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic auxin, were chosen for encapsulation. CPPU is a phenylurea derivative that shows strikingly strong cytokinin-like activity in plants, including delaying senescence. It is highly water insoluble, but soluble in organic solvents. It is widely used in a variety of crops, particularly kiwifruit and table grapes. Delivery of CPPU safely, efficiently and at the appropriate dosage is a priority as overdosing or incorrect timing of application causes detrimental effects on fruit firmness and other quality attributes. Auxins are also a group of plant hormone. 2,4-D is a synthetic auxin which has been widely used at high concentrations as a herbicide, at medium concentrations for fruit thinning, and at low concentrations promotes root initiation, but at even lower concentrations promote root elongation. Consequently, careful control of dosage is required to obtain the desired effect.  The nanoemulsion system developed was water/polysorbate 80/glycerol/soybean oil. The active ingredient, CPPU, was incorporated into the nanoemulsion via the oil phase in a pre-concentrate which was then crash diluted to yield the final nanoemulsion. Nanoemulsions are created only when the concentrate is located in the bicontinuous or oil-in-water microemulsion regions of the phase diagram. The droplet size of the nanoemulsions was measured using dynamic light scattering with droplets ranging in size from 30 – 100 nm. The CPPU-loaded nanoemulsions were stable for more than three days.  To determine if the nanoemulsion was an effective delivery system, a leaf senescence bioassay was conducted to test the senescence-delaying effect of the CPPU-loaded nanoemulsions when applied to explants. The nanoemulsions were applied directly to the leaves of dwarf bean explants. Chlorophyll was extracted from the leaves and measured spectrophotometrically before and several days following treatment. The CPPU-loaded nanoemulsions enhanced the effectiveness of CPPU in delaying leaf senescence compared with the control experiments, including direct application of CPPU. A >10-fold reduction in CPPU concentration was achieved.  The second delivery method was a solid-state preparation, using halloysite clay nanotubes loaded with 2,4-D. A rooting bioassay using mung bean explants was used for proof of concept. Application of 2,4-D nanotubes to the cut end of a young stem, without roots, stimulated root formation compared to controls after 10 days and at a lower applied concentration. The retardation of root elongation, relative to controls after 13 days, potentially indicated continued slow release of the active ingredient from the nanotubes.  Results obtained from this research indicate that nano-formulations have the potential to deliver biologically active compounds to plants in the horticultural and agricultural sectors at effective concentrations lower than in current usage.</p>


2021 ◽  
Author(s):  
◽  
Nurul Akmar Binti Che Zaudin

<p>Efficient and effective delivery of fertilisers, herbicides, pesticides and growth regulating compounds to plants is the subject of much ongoing research. The objective of this research was to develop nano-formulations for delivery of compounds to plants. Two formulations were developed: the first was solution-based focused on encapsulation of the active ingredient in a nanoemulsion. Nanoemulsions should be ideal for facilitating transfer of compounds to plant leaves as their size correlates well with the nanoscale surface features of leaves, achieving significantly greater total contact area between the oil droplets and the leaves. The second nano-formulation was solid-state based, focused on locating the active ingredient within the tubules of a nanotube clay.  For proof-of-concept two synthetic plant hormones, N-phenyl-N‘-(2-chloro-4-pyridyl)urea (CPPU) or forchlorfenuron, a synthetic cytokinin, and 2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic auxin, were chosen for encapsulation. CPPU is a phenylurea derivative that shows strikingly strong cytokinin-like activity in plants, including delaying senescence. It is highly water insoluble, but soluble in organic solvents. It is widely used in a variety of crops, particularly kiwifruit and table grapes. Delivery of CPPU safely, efficiently and at the appropriate dosage is a priority as overdosing or incorrect timing of application causes detrimental effects on fruit firmness and other quality attributes. Auxins are also a group of plant hormone. 2,4-D is a synthetic auxin which has been widely used at high concentrations as a herbicide, at medium concentrations for fruit thinning, and at low concentrations promotes root initiation, but at even lower concentrations promote root elongation. Consequently, careful control of dosage is required to obtain the desired effect.  The nanoemulsion system developed was water/polysorbate 80/glycerol/soybean oil. The active ingredient, CPPU, was incorporated into the nanoemulsion via the oil phase in a pre-concentrate which was then crash diluted to yield the final nanoemulsion. Nanoemulsions are created only when the concentrate is located in the bicontinuous or oil-in-water microemulsion regions of the phase diagram. The droplet size of the nanoemulsions was measured using dynamic light scattering with droplets ranging in size from 30 – 100 nm. The CPPU-loaded nanoemulsions were stable for more than three days.  To determine if the nanoemulsion was an effective delivery system, a leaf senescence bioassay was conducted to test the senescence-delaying effect of the CPPU-loaded nanoemulsions when applied to explants. The nanoemulsions were applied directly to the leaves of dwarf bean explants. Chlorophyll was extracted from the leaves and measured spectrophotometrically before and several days following treatment. The CPPU-loaded nanoemulsions enhanced the effectiveness of CPPU in delaying leaf senescence compared with the control experiments, including direct application of CPPU. A >10-fold reduction in CPPU concentration was achieved.  The second delivery method was a solid-state preparation, using halloysite clay nanotubes loaded with 2,4-D. A rooting bioassay using mung bean explants was used for proof of concept. Application of 2,4-D nanotubes to the cut end of a young stem, without roots, stimulated root formation compared to controls after 10 days and at a lower applied concentration. The retardation of root elongation, relative to controls after 13 days, potentially indicated continued slow release of the active ingredient from the nanotubes.  Results obtained from this research indicate that nano-formulations have the potential to deliver biologically active compounds to plants in the horticultural and agricultural sectors at effective concentrations lower than in current usage.</p>


2021 ◽  
Author(s):  
◽  
Nurul Akmar Binti Che Zaudin

<p>Efficient and effective delivery of fertilisers, herbicides, pesticides and growth regulating compounds to plants is the subject of much ongoing research. The objective of this research was to develop nano-formulations for delivery of compounds to plants. Two formulations were developed: the first was solution-based focused on encapsulation of the active ingredient in a nanoemulsion. Nanoemulsions should be ideal for facilitating transfer of compounds to plant leaves as their size correlates well with the nanoscale surface features of leaves, achieving significantly greater total contact area between the oil droplets and the leaves. The second nano-formulation was solid-state based, focused on locating the active ingredient within the tubules of a nanotube clay. For proof-of-concept two synthetic plant hormones, N-phenyl-N‘-(2-chloro-4-pyridyl)urea (CPPU) or forchlorfenuron, a synthetic cytokinin, and 2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic auxin, were chosen for encapsulation. CPPU is a phenylurea derivative that shows strikingly strong cytokinin-like activity in plants, including delaying senescence. It is highly water insoluble, but soluble in organic solvents. It is widely used in a variety of crops, particularly kiwifruit and table grapes. Delivery of CPPU safely, efficiently and at the appropriate dosage is a priority as overdosing or incorrect timing of application causes detrimental effects on fruit firmness and other quality attributes. Auxins are also a group of plant hormone. 2,4-D is a synthetic auxin which has been widely used at high concentrations as a herbicide, at medium concentrations for fruit thinning, and at low concentrations promotes root initiation, but at even lower concentrations promote root elongation. Consequently, careful control of dosage is required to obtain the desired effect. The nanoemulsion system developed was water/polysorbate 80/glycerol/soybean oil. The active ingredient, CPPU, was incorporated into the nanoemulsion via the oil phase in a pre-concentrate which was then crash diluted to yield the final nanoemulsion. Nanoemulsions are created only when the concentrate is located in the bicontinuous or oil-in-water microemulsion regions of the phase diagram. The droplet size of the nanoemulsions was measured using dynamic light scattering with droplets ranging in size from 30 – 100 nm. The CPPU-loaded nanoemulsions were stable for more than three days. To determine if the nanoemulsion was an effective delivery system, a leaf senescence bioassay was conducted to test the senescence-delaying effect of the CPPU-loaded nanoemulsions when applied to explants. The nanoemulsions were applied directly to the leaves of dwarf bean explants. Chlorophyll was extracted from the leaves and measured spectrophotometrically before and several days following treatment. The CPPU-loaded nanoemulsions enhanced the effectiveness of CPPU in delaying leaf senescence compared with the control experiments, including direct application of CPPU. A >10-fold reduction in CPPU concentration was achieved. The second delivery method was a solid-state preparation, using halloysite clay nanotubes loaded with 2,4-D. A rooting bioassay using mung bean explants was used for proof of concept. Application of 2,4-D nanotubes to the cut end of a young stem, without roots, stimulated root formation compared to controls after 10 days and at a lower applied concentration. The retardation of root elongation, relative to controls after 13 days, potentially indicated continued slow release of the active ingredient from the nanotubes. Results obtained from this research indicate that nano-formulations have the potential to deliver biologically active compounds to plants in the horticultural and agricultural sectors at effective concentrations lower than in current usage.</p>


2021 ◽  
Author(s):  
◽  
Nurul Akmar Binti Che Zaudin

<p>Efficient and effective delivery of fertilisers, herbicides, pesticides and growth regulating compounds to plants is the subject of much ongoing research. The objective of this research was to develop nano-formulations for delivery of compounds to plants. Two formulations were developed: the first was solution-based focused on encapsulation of the active ingredient in a nanoemulsion. Nanoemulsions should be ideal for facilitating transfer of compounds to plant leaves as their size correlates well with the nanoscale surface features of leaves, achieving significantly greater total contact area between the oil droplets and the leaves. The second nano-formulation was solid-state based, focused on locating the active ingredient within the tubules of a nanotube clay. For proof-of-concept two synthetic plant hormones, N-phenyl-N‘-(2-chloro-4-pyridyl)urea (CPPU) or forchlorfenuron, a synthetic cytokinin, and 2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic auxin, were chosen for encapsulation. CPPU is a phenylurea derivative that shows strikingly strong cytokinin-like activity in plants, including delaying senescence. It is highly water insoluble, but soluble in organic solvents. It is widely used in a variety of crops, particularly kiwifruit and table grapes. Delivery of CPPU safely, efficiently and at the appropriate dosage is a priority as overdosing or incorrect timing of application causes detrimental effects on fruit firmness and other quality attributes. Auxins are also a group of plant hormone. 2,4-D is a synthetic auxin which has been widely used at high concentrations as a herbicide, at medium concentrations for fruit thinning, and at low concentrations promotes root initiation, but at even lower concentrations promote root elongation. Consequently, careful control of dosage is required to obtain the desired effect. The nanoemulsion system developed was water/polysorbate 80/glycerol/soybean oil. The active ingredient, CPPU, was incorporated into the nanoemulsion via the oil phase in a pre-concentrate which was then crash diluted to yield the final nanoemulsion. Nanoemulsions are created only when the concentrate is located in the bicontinuous or oil-in-water microemulsion regions of the phase diagram. The droplet size of the nanoemulsions was measured using dynamic light scattering with droplets ranging in size from 30 – 100 nm. The CPPU-loaded nanoemulsions were stable for more than three days. To determine if the nanoemulsion was an effective delivery system, a leaf senescence bioassay was conducted to test the senescence-delaying effect of the CPPU-loaded nanoemulsions when applied to explants. The nanoemulsions were applied directly to the leaves of dwarf bean explants. Chlorophyll was extracted from the leaves and measured spectrophotometrically before and several days following treatment. The CPPU-loaded nanoemulsions enhanced the effectiveness of CPPU in delaying leaf senescence compared with the control experiments, including direct application of CPPU. A >10-fold reduction in CPPU concentration was achieved. The second delivery method was a solid-state preparation, using halloysite clay nanotubes loaded with 2,4-D. A rooting bioassay using mung bean explants was used for proof of concept. Application of 2,4-D nanotubes to the cut end of a young stem, without roots, stimulated root formation compared to controls after 10 days and at a lower applied concentration. The retardation of root elongation, relative to controls after 13 days, potentially indicated continued slow release of the active ingredient from the nanotubes. Results obtained from this research indicate that nano-formulations have the potential to deliver biologically active compounds to plants in the horticultural and agricultural sectors at effective concentrations lower than in current usage.</p>


2021 ◽  
Vol 7 (11) ◽  
pp. 994
Author(s):  
Jiao Qin ◽  
Jing-Qiu Feng ◽  
Wei Zhang ◽  
Shi-Bao Zhang

Mycorrhizal mutualisms are vital for orchids through germination to adulthood. Fungal species diversity and community composition vary across seasons and plant development stages and affect plant survival, adaptation, and community maintenance. Knowledge of the temporal turnover of mycorrhizal fungi (OMF) remains poorly understood in the eco-physiologically diverse orchids (especially in epiphytic orchids), although it is important to understand the function and adaptation of mycorrhizae. Some species of Pleione are epiphytic plants with annual roots and may recruit different fungal partners during their root lifecycle. Based on continuous samplings of Pleione bulbocodioides during a whole root lifecycle, we characterized the fungal temporal dynamics using Illumina sequencing of the ITS2 region. Our data showed that the plants of P. bulbocodioides were quickly colonized by OMF at root emergence and had a constant OMF composition throughout one root lifecycle, although the OMF richness declined with root aging after a peak occurrence during root elongation. In contrast, the richness of root-inhabiting fungal endophytes kept increasing with root aging and more drastic turnovers were found in their species compositions. Our findings of OMF temporal turnover contribute to further understanding of mycorrhizal associations and adaptation of Orchidaceae and will benefit orchid resource conservation and utilization.


Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3110
Author(s):  
Lidiya Vysotskaya ◽  
Leylya Timergalina ◽  
Guzel Akhiyarova ◽  
Alla Korobova ◽  
Vadim Fedyaev ◽  
...  

Changes in root elongation are important for the acquisition of mineral nutrients by plants. Plant hormones, cytokinins, and abscisic acid (ABA) and their interaction are important for the control of root elongation under changes in the availability of ions. However, their role in growth responses to supra-optimal concentrations of nitrates and phosphates has not been sufficiently studied and was addressed in the present research. Effects of supra-optimal concentrations of these ions on root elongation and distribution of cytokinins between roots and shoots were studied in ABA-deficient barley mutant Az34 and its parental variety, Steptoe. Cytokinin concentration in the cells of the growing root tips was analyzed with the help of an immunohistochemical technique. Increased concentrations of nitrates and phosphates led to the accumulation of ABA and cytokinins in the root tips, accompanied by a decline in shoot cytokinin content and inhibition of root elongation in Steptoe. Neither of the effects were detected in Az34, suggesting the importance of the ability of plants to accumulate ABA for the control of these responses. Since cytokinins are known to inhibit root elongation, the effect of supra-optimal concentration of nitrates and phosphates on root growth is likely to be due to the accumulation of cytokinins brought about by ABA-induced inhibition of cytokinin transport from roots to shoots.


2021 ◽  
Vol 2 ◽  
pp. 100024
Author(s):  
Dane Lamb ◽  
Girish Choppala ◽  
Marjana Yeasmin ◽  
Sepide Abbasi ◽  
Liang Wang ◽  
...  
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