A quantitative study of lateral branching in petunia

2003 ◽  
Vol 30 (9) ◽  
pp. 987 ◽  
Author(s):  
Kimberley C. Snowden ◽  
Carolyn A. Napoli

The monopodial shoot axis of petunia (Petunia hybrida Vilm) has two different patterns of branch development. Basal lateral branching develops acropetally and is limited to a discrete number of nodes that correlate with the late rosette phase of growth (Zone II). Two zones of suppressed buds immediately precede and follow this zone of branching. Apical branching occurs in response to flowering, develops in a basipetal direction, and is restricted to the distal-most nodes on the monopodial axis. When grown under a short-day regime, an extension to the basal branching zone occurs, and growth of the main shoot axis is retarded. The sym1 mutant has an overall decrease in basal lateral branching compared with wild type whereas the three dad mutants have increased basal branching. The dad1-1 and dad2-1 mutants have no initial zone of suppressed branching whereas the dad3 mutant has a similar Zone II to wild type, but with a greater potential to form branches within this zone. The dad1-1 mutant exhibits delayed flowering, but the dad1-1 sym1 double mutant flowers at a similar node number to wild-type and branching is similar to dad1-1 indicating that these two aspects of the mutant dad1-1 phenotype are independent.


Author(s):  
Hui-Yu Chen ◽  
Shan-Hua Lin ◽  
Ling-Hsin Cheng ◽  
Jeng-Jong Wu ◽  
Yi-Chen Lin ◽  
...  

Abstract Compared with root development regulated by external nutrients, less is known about how internal nutrients are monitored to control plasticity of shoot development. In this study, we characterize an Arabidopsis thaliana transceptor, NRT1.13 (NPF4.4), of the NRT1/PTR/NPF family. Different from most NRT1 transporters, NRT1.13 does not have the conserved proline residue between transmembrane domains 10 and 11; an essential residue for nitrate transport activity in CHL1/NRT1.1/NPF6.3. As expected, when expressed in oocytes, NRT1.13 showed no nitrate transport activity. However, when Ser 487 at the corresponding position was converted back to proline, NRT1.13 S487P regained nitrate uptake activity, suggesting that wild-type NRT1.13 cannot transport nitrate but can bind it. Subcellular localization and β-glucuronidase reporter analyses indicated that NRT1.13 is a plasma membrane protein expressed at the parenchyma cells next to xylem in the petioles and the stem nodes. When plants were grown with a normal concentration of nitrate, nrt1.13 showed no severe growth phenotype. However, when grown under low-nitrate conditions, nrt1.13 showed delayed flowering, increased node number, retarded branch outgrowth, and reduced lateral nitrate allocation to nodes. Our results suggest that NRT1.13 is required for low-nitrate acclimation and that internal nitrate is monitored near the xylem by NRT1.13 to regulate shoot architecture and flowering time.



2000 ◽  
Vol 78 (5) ◽  
pp. 591-599 ◽  
Author(s):  
Ari-Pekka Huhta ◽  
Juha Tuomi ◽  
Pasi Rautio

Apical dominance is advantageous in conditions favoring rapid growth in height and unbranched architecture. The cost of apical dominance, on the other hand, should be expressed in conditions where fecundity increases along with an increasing number of branches. Apical damage can be used to measure such costs: when suppressed meristems are released from apical inhibition, the vegetative and reproductive productivity of initially unbranched plants should increase owing to the regrowth and increased branch development following damage. We studied these regrowth responses in two monocarpic herbs, Erysimum strictum P. Gaertn., B. Mey., and Scherb. and Rhinanthus minor L., after both apical damage (10% of the shoot cut) and more extensive damage (50 and 75% cutting). Both species tolerated apical damage, although severe damage had detrimental effects on the performance of both, especially R. minor. Apical damage had positive effects on most of the measured performance parameters of Erysimum. However, the success of seed germination collapsed, presumably due to delayed flowering and less successful pollination. The response was parallel in Rhinanthus; apical damage affected neither the vegetative biomass nor fecundity, but heavier damage, especially 75% clipping, led to severe reductions in most performance measures. The differences in regrowth responses are presumably due to the different habitat requirements of the species. Rhinanthus prefers relatively dense vegetation and starts to branch and produce flowers after a certain threshold in height has been reached, whereas Erysimum prefers gaps in vegetation. In this species, unbranched architecture may be favored in closed vegetation and branched architecture in less competitive habitats. In both species, fruit production correlated positively with the number of branches in both control and clipped plants, which is consistent with the assumption of the cost of apical dominance.Key words: apical dominance, competition, damage, meristem, overcompensation, regrowth.



2019 ◽  
Vol 10 (2) ◽  
pp. 797-810
Author(s):  
Rajdeep S. Khangura ◽  
Bala P. Venkata ◽  
Sandeep R. Marla ◽  
Michael V. Mickelbart ◽  
Singha Dhungana ◽  
...  

We previously demonstrated that maize (Zea mays) locus very oil yellow1 (vey1) encodes a putative cis-regulatory expression polymorphism at the magnesium chelatase subunit I gene (aka oil yellow1) that strongly modifies the chlorophyll content of the semi-dominant Oy1-N1989 mutants. The vey1 allele of Mo17 inbred line reduces chlorophyll content in the mutants leading to reduced photosynthetic output. Oy1-N1989 mutants in B73 reached reproductive maturity four days later than wild-type siblings. Enhancement of Oy1-N1989 by the Mo17 allele at the vey1 QTL delayed maturity further, resulting in detection of a flowering time QTL in two bi-parental mapping populations crossed to Oy1-N1989. The near isogenic lines of B73 harboring the vey1 allele from Mo17 delayed flowering of Oy1-N1989 mutants by twelve days. Just as previously observed for chlorophyll content, vey1 had no effect on reproductive maturity in the absence of the Oy1-N1989 allele. Loss of chlorophyll biosynthesis in Oy1-N1989 mutants and enhancement by vey1 reduced CO2 assimilation. We attempted to separate the effects of photosynthesis on the induction of flowering from a possible impact of chlorophyll metabolites and retrograde signaling by manually reducing leaf area. Removal of leaves, independent of the Oy1-N1989 mutant, delayed flowering but surprisingly reduced chlorophyll contents of emerging leaves. Thus, defoliation did not completely separate the identity of the signal(s) that regulates flowering time from changes in chlorophyll content in the foliage. These findings illustrate the necessity to explore the linkage between metabolism and the mechanisms that connect it to flowering time regulation.



1970 ◽  
Vol 21 (6) ◽  
pp. 893 ◽  
Author(s):  
WJ Collins ◽  
Y Aitken

The removal of fully expanded leaves delayed flowering by up to 30 days in subterranean clover cv. Mt. Barker sown in winter at Melbourne (38�S.). This effect on flowering was attributable partly to a delay in flower initiation and partly to a slower rate of leaf appearance after flower initiation. Thus leaf removal may be added to the factors already known to influence flower initiation in subterranean clover. When plants were grown under a 24 hr photoperiod. leaf removal had no effect on flower initiation; the slight delay that leaf removal caused in flowering was therefore due entirely to its effect in reducing the rate of leaf appearance. In other experiments leaf removal delayed the time of flower initiation but had no effect on the rate of leaf appearance. The effect of leaf removal on the time of flowering on the main shoot in lateral-dominant plants (as occur in the field) was qualitatively the same as in plants from which the laterals had been removed. Grazing management of subterranean clover which results in severe defoliation during early growth may delay flowering to such an extent that seed production is reduced substantially, and persistence thereby prejudiced.



2002 ◽  
Vol 29 (12) ◽  
pp. 1500 ◽  
Author(s):  
Richard A. Jorgensen ◽  
Qiudeng Que ◽  
Carolyn A. Napoli

Transgenes designed to overexpress anthocyanin genes An6 (encoding dihydroflavonol-4-reductase) or Hf1 (encoding flavonoid-3′,5′-hydroxylase) in Petunia hybrida L. produced flower colour phenotypes similar to those caused by sense cosuppression of chalcone synthase (Chs) genes. However, unlike Chs, sense cosuppression of An6 and Hf1 resulted in female infertility in transgenotes exhibiting complete phenotypic suppression of anthocyanins. Female sterility appeared to be due to embryo abortion, with discolouration of ovules first appearing about 4 d post-fertilization, followed by gradual collapse of the ovule. Pollen from cosuppressed, female-sterile transgenotes placed on wild-type stigmas produced normal seed set, indicating that sterility of cosuppressed plants was maternally controlled. We suggest an hypothesis that cosuppression of An6 and Hf1 leads to accumulation of dihydroflavonols in the seed coat, a maternal tissue, and that this accumulation inhibits embryo growth, either directly or indirectly. In this hypothesis, direct inhibition of embryo growth would require that dihydroflavonols diffuse from the seed coat into the embryo and act there, whereas indirect inhibition would require that dihydroflavonols interfere with some capacity of the seed coat to promote embryo growth.



Genetics ◽  
1984 ◽  
Vol 106 (3) ◽  
pp. 501-508
Author(s):  
Anton G M Gerats ◽  
Eliane Farcy ◽  
Marco Wallroth ◽  
Steven P C Groot ◽  
André Schram

ABSTRACT A mutable allele of the An1 locus in Petunia hybrida has given rise to a multiple series of stable derivative alleles. Anthocyanin concentration in mature flowers of these mutants (an1  +/p/an1) decreases from the wild-type red to the recessive white in a continuous series. Anthocyanin composition changes regularly: the ratio of peonidin to cyanidin is 3.5 for an an1  +/+/an1 and 1.2 for an an1  +/p5/an1 mutant. Analysis of anthocyanins during flower development indicates that these differences in composition are due to the specific state of the An1 locus and not to anthocyanin concentration. Anthocyanin concentration in flowers of the allelic series for An1 correlates with the activity of the enzymes UDP-glucose: flavonoid-3-O-glucosyltransferase and SAM: anthocyanin-3′-O-methyltransferase. The same correlations were found for members of a comparable allelic series at the An2 locus. The possibility that the correlation between the enzyme activities is due to the occurrence of a multienzyme complex is discussed.



2021 ◽  
Author(s):  
Wasim A Sayyad ◽  
Thomas D Pollard

Cytokinesis nodes are assemblies of stoichiometric ratios of proteins associated with the plasma membrane, which serve as precursors for the contractile ring during cytokinesis by fission yeast. The total number of nodes is uncertain, because of the limitations of the methods used previously. Here we used the ~140 nm resolution of Airyscan confocal microscopy to resolve a large population of dim, unitary cytokinesis nodes in 3D reconstructions of whole fission yeast cells. Wild-type fission yeast cells make about 200 unitary cytokinesis nodes. Most, but not all of these nodes condense into a contractile ring. The number of cytokinesis nodes scales with cell size in four strains tested, although wide rga4Δ mutant cells form somewhat fewer cytokinesis nodes than expected from the overall trend. The surface density of Pom1 kinase on the plasma membrane around the equators of cells is similar with a wide range of node numbers, so Pom1 does not control cytokinesis node number. However, varying protein concentrations with the nmt1 promoter showed that the numbers of nodes increase above a baseline of about 200 with the total cellular concentration of either Pom1 or the kinase Cdr2.



2021 ◽  
Author(s):  
Sabine Scandola ◽  
Devang Mehta ◽  
Maria C Rodriguez ◽  
Qiaomu Li ◽  
Richard Glen Uhrig

Plants are able to sense changes in their light environments, such as the onset of day and night, as well as anticipate these changes in order to adapt and survive. Central to this ability is the plant circadian clock, a molecular circuit that precisely orchestrates plant cell processes over the course of a day. REVEILLE proteins (RVEs) are recently discovered members of the plant circadian circuitry that activate the evening complex and PRR genes to maintain regular circadian oscillation. The RVE 8 protein and its two homologs, RVE 4 and 6, have been shown to limit the length of the circadian period, with rve 4 6 8 triple-knockout plants possessing an elongated period along with increased leaf surface area, biomass and delayed flowering relative to wild-type Col-0 plants. Here, using a multi-omics approach consisting of phenomics, transcriptomics, proteomics, and metabolomics we demonstrate how RVE8-like proteins impact diel plant cell function and draw novel connections to a number of plant cell processes that underpin the growth and development phenotypes observed in rve 4 6 8 plants. In particular, we reveal that loss of RVE8-like proteins results in altered carbohydrate, organic acid and lipid metabolism, including a starch excess phenotype at ZT0. We further demonstrate that RVE8-like proteins have a unique impact on the abundance and phosphorylation of 26S proteasome subunits, in addition to impacting the abundance and phosphorylation status of a number of protein kinases. Overall, this robust, multi-omic dataset, provides substantial new insights into RVE8-like protein function and the far reaching impact RVE8-like proteins have on the diel plant cell environment.



HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 131-133 ◽  
Author(s):  
Ilias F. Ilias ◽  
Nihal Rajapakse

The objective of this research was to investigate if brief exposure to end-of-the-day (EOD) red (R) or far red (FR) light can overcome the flowering delay of petunia (Petunia ×hybrida Vilm.-Andr. `Countdown Burgundy') grown under FR deficient greenhouse environments with no adverse effects on stem elongation. Plants were grown under clear, FR, and R light absorbing greenhouse films (control, AFR, and AR films, respectively) and exposed to R or FR light at the end of the photoperiod for 15 minutes. At flowering, main stem of plants grown under the AR film was about 17% longer and that of AFR film grown plants (without EOD treatment) was about 50% shorter than control plants. EOD-R light reduced stem elongation of control plants but had no effect on AFR or AR film-grown plants. EOD-FR light increased stem elongation in plants grown under AR and AFR films but the percentage increase was greater under AFR film (7%, 19%, and 64% increase in control, AR, and AFR films, respectively). However, plants that received EOD-FR light under AFR film were 25% shorter than control plants that received no EOD light. AFR film delayed flowering by 11 days but AR film had no effect. Fifteen-minute exposure to EOD-R or -FR light had no effect on flowering under control and AFR film. Although the exposure to brief EOD-FR partially increased stem elongation, it was not sufficient to accelerate flowering. Treatments to enhance flowering can cause stem elongation. Therefore, care should be taken to avoid improper crop timing, especially with long-day plants.



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