AN IRREVERSIBLE GENE-INDUCED PLASTID MUTATION

1949 ◽  
Vol 27c (4) ◽  
pp. 172-178 ◽  
Author(s):  
T. J. Arnason ◽  
G. W. R. Walker
Keyword(s):  
Total Population ◽  
Female Parent ◽  
Single Pair ◽  
Albino Plants ◽  
Plastid Mutation ◽  
Normal Green ◽  
Green Tissue ◽  
White Tissue ◽  
Normal Gene ◽  
Plastid Transmission

When plants of a variegated barley are self-pollinated, they produce few variegated and many albino offspring. In different years the proportion of albino plants has ranged from 80.2 to 93.1% of the total population. Seed from heads having much green tissue gave rise to a much larger proportion of variegated plants than did seed from heads with more white tissue. Maternal inheritance of plastids is probably the cause of this difference. In crosses F1 plants are green, variegated, or albino if the ♂ parent is variegated, but if the ♂ parent is green all the progeny are green. The albino plastids thus apparently do not mutate back to normal in the presence of the normal gene. In some F2 populations deviation from a ratio of 3 green: 1 others is insignificant, in other populations significant deviations, attributed to irregularities of plastid mutation and segregation, occur. F3 results support the hypothesis that a single pair of genes affecting plastids is segregating in hybrids. The normal (green) gene is dominant if "green" proplastids are present in the egg but not dominant if the proplastids are all "white". From cytological observations on sperms and eggs as well as from the genetic results, it is considered likely that direct plastid transmission to zygotes is exclusively from the female parent.

scholarly journals Symptom Development and Susceptibility of Dwarf Cherry Tomato to Tomato Irregular Ripening, A Fruit Disorder Induced by Silverleaf Whitefly

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 678b-678
Author(s):  
S. Hanif-Khan ◽  
R.C. Bullock ◽  
P.J. Stoffella ◽  
J.K. Brecht ◽  
C.A. Powell ◽  
...  
Keyword(s):  
Lycopersicon Esculentum ◽  
Oviposition Preference ◽  
Silverleaf Whitefly ◽  
Bemisia Argentifolii ◽  
Cherry Tomato ◽  
Symptom Development ◽  
Green Tissue ◽  
White Tissue

Silverleaf whitefly (SLW) (Bemisia argentifolii Bellows and Perring) feeding has been associated with development of tomato irregular ripening (TIR) symptoms. Four dwarf cultivars of cherry tomato (Lycopersicon esculentum L.) were infested with adult SLW to observe oviposition preference, tolerance and TIR symptom development. Oviposition preference was observed at low SLW population. Florida Petite was the most preferred and Micro-Tom the least preferred cultivar, with Florida Lanai and Florida Basket intermediate. Each cultivar exhibited TIR symptoms associated with feeding by the SLW. TIR fruit symptoms were expressed as longitudinal red streaks with yellow, green, pink or red blotches externally, and white, yellow or green tissue internally. External TIR symptoms ranged from 32% (Micro-Tom) to 82% (Florida Basket). However, external symptoms disappeared from 34% (Florida Lanai) to 56% (Micro-Tom) of the fruits during ripening. SLW infested plants had 82% (Florida Lanai) to 99% (Florida Basket) of fruits with internal white tissue regardless of external symptoms. Tomatoes with TIR symptoms rarely ripened to a mature red, and sometimes had empty locules, were smaller in size and were seedless.

scholarly journals Female Fertility and Mating Type Distribution in a South African Population of Fusarium subglutinans f. sp.pini

1998 ◽  
Vol 64 (6) ◽  
pp. 2094-2095 ◽  
Author(s):  
H. Britz ◽  
M. J. Wingfield ◽  
T. A. Coutinho ◽  
W. F. O. Marasas ◽  
J. F. Leslie
Keyword(s):  
South African ◽  
Mating Type ◽  
Total Population ◽  
Female Parent ◽  
Pitch Canker ◽  
Effective Population ◽  
South African Population ◽  
Fusarium Subglutinans ◽  
Population Number ◽  
Canker Disease

ABSTRACT Fusarium subglutinans f. sp. pini is the causal agent of pitch canker disease of pines. The initial occurrence of F. subglutinans f. sp. pini in South Africa was limited to a single nursery, and isolates from this population are capable of reproducing sexually. We determined the effective population number, Ne , of this population by using mating type and male/hermaphrodite polymorphisms as indicators. The effective population number for mating type, Ne(mt) , is 99% of the count (total population), and that for male/hermaphrodite status, Ne(f) , is 42 to 46% of the count (total population). The number of strains that can function as the female parent limits the effective population number of this population. If this population is stable, then, depending upon assumptions about mutation and selection, sexual reproduction need occur only once per 26 to 153 asexual generations to maintain this level of sexual fertility.

Isotopic evidence for nitrogen exchange between autotrophic and heterotrophic tissues in variegated leaves

2016 ◽  
Vol 43 (3) ◽  
pp. 298 ◽  
Author(s):  
Cyril Abadie ◽  
Marlène Lamothe-Sibold ◽  
Françoise Gilard ◽  
Guillaume Tcherkez
Keyword(s):  
Nitrogen Deficiency ◽  
Co2 Assimilation ◽  
Isotopic Labelling ◽  
Nitrogenous Compounds ◽  
Isotopic Methods ◽  
Green Tissue ◽  
White Tissue ◽  
Natural Isotope Abundance ◽  
Nitrogen Exchange ◽  
The One

Many plant species or cultivars form variegated leaves in which blades are made of green and white sectors. On the one hand, there is little photosynthetic CO2 assimilation in white tissue simply because of the lack of functional chloroplasts and thus, leaf white tissue is heterotrophic and fed by photosynthates exported by leaf green tissue. On the other hand, it has been previously shown that the white tissue is enriched in nitrogenous compounds such as amino acids and polyamines, which can, in turn, be remobilised upon nitrogen deficiency. However, the origin of organic nitrogen in leaf white tissue, including the possible requirement for N-reduction in leaf green tissue before export to white tissue, has not been examined. Here, we took advantage of isotopic methods to investigate the source of nitrogen in the white tissue. A survey of natural isotope abundance (δ15N) and elemental composition (%N) in various variegated species shows no visible difference between white and green tissues, suggesting a common N source. However, there is a tendency for N-rich white tissue to be naturally 15N-enriched whereas in the model species Pelargonium × hortorum, white sectors are naturally 15N-depleted, indicating that changes in metabolic composition and/or N-partitioning may occur. Isotopic labelling with 15N-nitrate on illuminated leaf discs clearly shows that the white tissue assimilates little nitrogen and thus relies on nitrate reduction and metabolism in the green tissue. The N-sink represented by the white tissue is considerable, accounting for nearly 50% of total assimilated nitrate.

scholarly journals Ac-induced instability at the Xanthophyllic locus of tomato.

Genetics ◽  
1993 ◽  
Vol 134 (3) ◽  
pp. 931-942
Author(s):  
P W Peterson ◽  
J I Yoder
Keyword(s):  
Marker Gene ◽  
Chromosome Breakage ◽  
Chromosome 10 ◽  
Tomato Plants ◽  
Whole Plant ◽  
Green Tissue ◽  
F1 Progeny ◽  
White Tissue ◽  
Transgenic Tomatoes ◽  
And Control

Abstract To detect genomic instability caused by Ac elements in transgenic tomatoes, we used the incompletely dominant mutation Xanthophyllic-1 (Xa-1) as a whole plant marker gene. Xa-1 is located on chromosome 10 and in the heterozygote state causes leaves to be yellow. Transgenic Ac-containing tomato plants which differed in the location and number of their Ac elements were crossed to Xa-1 tester lines and F1 progeny were scored for aberrant somatic sectoring. Of 800 test and control F1 progeny screened, only four plants had aberrantly high levels of somatic sectors. Three of the plants had twin sectors consisting of green tissue adjacent to white tissue, and the other had twin sectors comprised of green tissue adjacent to tissue more yellow than the heterozygote background. Sectoring was inherited and the two sectoring phenotypes mapped to opposite homologs of chromosome 10; the green/yellow sectoring phenotype mapped in coupling to Xa-1 while the green/white sectoring phenotype mapped in repulsion. The two sectoring phenotypes cosegregated with different single, non-rearranged Acs, and loss of these Acs from the genome corresponded to the loss of sectoring. Sectoring was still observed after transposition of the Ac to a new site which indicated that sectoring was not limited to a single locus. In both sectored lines, meiotic recombination of the sectoring Ac to the opposite homolog caused the phenotype to switch between the green/yellow and the green/white phenotypes. Thus the two different sectoring phenotypes arose from the same Ac-induced mechanism; the phenotype depended on which chromosome 10 homolog the Ac was on. We believe that the twin sectors resulted from chromosome breakage mediated by a single intact, transposition-competent Ac element.

scholarly journals Development of Genic Male-sterile Watermelon Lines with Juvenile Albino Seedling Marker

HortScience ◽  
1996 ◽  
Vol 31 (3) ◽  
pp. 426-429 ◽  
Author(s):  
X.P. Zhang ◽  
B.B. Rhodes ◽  
W.V. Baird ◽  
W.C. Bridges ◽  
H.T. Skorupska
Keyword(s):  
Gene Flow ◽  
Citrullus Lanatus ◽  
Hybrid Plant ◽  
Male Sterile ◽  
Male Sterile Line ◽  
Cross Pollination ◽  
Albino Plants ◽  
Normal Green

This research was conducted to develop genic male-sterile lines of watermelon (Citrullus lanatus Matsum & Nakai) homozygous for the juvenile albino (ja) seedling marker. Male-sterile plants (msms) of the genic male-sterile line G17AB were crossed with a Dixielee plant that was heterozygous for the ja locus. Male-fertile, juvenile albino recombinants of the F2 progeny were self-pollinated, resulting in F3 progeny. The male-sterile normal green recombinants of the F2 progeny were crossed with an F1 hybrid plant with genotype MsmsJaja, and three populations (93JMSB-1, -2, and -3) were obtained from these crosses. Juvenile albino recombinants were confined to 93JMSB-1. Of the juvenile albino plants of 93JMSB-1, male-sterile plants were sib-crossed with male-fertile plants, resulting in 93JMSB-1-1. Progeny of 93JMSB-1-1 was homozygous for ja and segregated for ms in a 127 male-sterile: 128 male-fertile ratio, fitting a 1:1 ratio. The male-sterile juvenile albino plants of F3 were crossed with male-fertile juvenile albino plants of 93JMSB-1, resulting in 93JMSF3-1 and -2. Plants 93JMSF3-1 and -2 were homozygous for ja but segregated for ms at 10 male-sterile: 13 male-fertile and 15 male-sterile: 19 male-fertile for 93JMSF3-1 and 93JMSF3-2, respectively, fitting the 1:1 ratio. These three genic male-sterile lines with the ja seedling marker provide valuable germplasm for introducing ms and ja genes into diverse genetic backgrounds and for studying cross-pollination and gene flow in watermelon populations.

Porphyrinsynthesis in Isolated Particles from Tissue Cultures of Tobacco

1971 ◽  
Vol 26 (9) ◽  
pp. 908-912 ◽  
Author(s):  
Hansjörg A. W. Schneider
Keyword(s):  
Nicotiana Tabacum ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Tissue Cultures ◽  
Green Tissue ◽  
White Tissue

Particles from green and white tissue cultures of Nicotiana tabacum were fractionated by differential and density gradient centrifugation. Besides mitochondria, microbodies and (broken) chloroplasts particles were found able to metabolize 5-amino-levulinate to porphobilinogen and porphobilinogen to uroporphyrinogen. Succinyl-CoA was not synthetized by them but by mitochondria. The porphyrin forming particles had a density of about 1.21 g/cm3 and were accumulated in fractions between mitochondria (1.19 g/cm3) and microbodies (1.23 g/cm3). Small differencies in density were found between particles from white and green tissue cultures. The data available suggest that the porphyrin synthetizing particles are proplastids or leucoplasts.

Seagrass leaf reddening alters the microbiome of Zostera muelleri

2020 ◽  
Vol 646 ◽  
pp. 29-44
Author(s):  
V Hurtado-McCormick ◽  
T Kahlke ◽  
D Krix ◽  
A Larkum ◽  
PJ Ralph ◽  
...  
Keyword(s):  
Significant Proportion ◽  
Amplicon Sequencing ◽  
High Irradiance ◽  
Rrna Gene ◽  
Core Microbiome ◽  
Microbiome Composition ◽  
Operational Taxonomic Units ◽  
Normal Green ◽  
White Tissue ◽  
Leaf Reddening

Seagrasses host an extremely diverse microbiome that plays fundamental roles in seagrass health and productivity but may be sensitive to shifts in host physiology. Here, we observed a leaf reddening phenomenon in Zostera muelleri and characterized bacterial assemblages associated with green and reddened leaves to determine whether this change in leaf pigmentation stimulates shifts in the seagrass microbiome. Using 16S rRNA gene amplicon sequencing, we observed that the microbiome associated with 4 different leaf pigmentation categories (i.e. green, white, purple and black) differed significantly, with substantial changes in microbiome composition when the tissue is whitened (non-pigmented). Actinobacteria, Rhodobacteraceae, Erythrobacter, Sulfitobacter and Granulosicoccus were enriched in black and/or purple tissues and discriminated these microbiomes from those associated with green leaves. Contrastingly, all ‘discriminatory’ zero-radius operational taxonomic units (zOTUs) were depleted within the communities associated with white samples. While 40% of the abundant zOTUs identified were exclusively associated with a single pigmentation category, only 3% were shared across all categories, indicating partitioning of the phyllosphere microbiome. However, a significant proportion of the ‘normal’ (green) leaf core microbiome was also retained in the core communities associated with black (70%) and purple (70%) tissues. Contrastingly, no core zOTUs were maintained in the white tissues. These results indicate that environmentally driven physiological shifts in seagrasses, such as leaf reddening expressed in response to high irradiance, can impact the seagrass leaf microbiome, resulting in significant shifts in the microbiome of reddened leaves with the most extreme expression (in white tissue of reddened leaves).

POLLEN CONTAMINATION OF BROMEGRASS (Bromus inermis Leyss.) IN THE GREENHOUSE

1981 ◽  
Vol 61 (3) ◽  
pp. 741-744 ◽  
Author(s):  
G. M. DUNN ◽  
H. Z. LEA
Keyword(s):  
Female Parent ◽  
Bromus Inermis ◽  
Pollen Contamination ◽  
Normal Green ◽  
Virescent Mutant ◽  
Spatial Isolation ◽  
Pollen Distribution

Contamination of bromegrass (Bromus inermis Leyss.) by wind-blown pollen was measured in the greenhouse using a homozygous recessive virescent mutant as the female parent. Pollen distribution was enhanced by manual shaking of male parents and by use of a fan. In previous tests, the mutant produced less than 0.005% normal green seedlings upon selfing. In this trial, green seedlings averaged 81.1, 40.8, 13.1, 6.9 and 1.1% among the progenies of the mutant when it was grown at 0, 1.5, 3.0, 4.5 and 7.5 m, respectively, from normal green parents. We conclude that satisfactory spatial isolation of several groups of bromegrass clones for breeding can be readily obtained in a greenhouse.

From the Oort cloud to Halley-type comets

1999 ◽  
Vol 173 ◽  
pp. 327-338 ◽  
Author(s):  
J.A. Fernández ◽  
T. Gallardo
Keyword(s):  
Total Population ◽  
Complex Function ◽  
Dynamical Evolution ◽  
Oort Cloud ◽  
Capture Process ◽  
Influx Rate ◽  
Short Period ◽  
Dynamical Properties ◽  
Orbital Periods ◽  
Probability Of Capture

AbstractThe Oort cloud probably is the source of Halley-type (HT) comets and perhaps of some Jupiter-family (JF) comets. The process of capture of Oort cloud comets into HT comets by planetary perturbations and its efficiency are very important problems in comet ary dynamics. A small fraction of comets coming from the Oort cloud − of about 10−2− are found to become HT comets (orbital periods < 200 yr). The steady-state population of HT comets is a complex function of the influx rate of new comets, the probability of capture and their physical lifetimes. From the discovery rate of active HT comets, their total population can be estimated to be of a few hundreds for perihelion distancesq <2 AU. Randomly-oriented LP comets captured into short-period orbits (orbital periods < 20 yr) show dynamical properties that do not match the observed properties of JF comets, in particular the distribution of their orbital inclinations, so Oort cloud comets can be ruled out as a suitable source for most JF comets. The scope of this presentation is to review the capture process of new comets into HT and short-period orbits, including the possibility that some of them may become sungrazers during their dynamical evolution.

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