Chloroplast Counts Research Articles

Production of haploids in Gerbera jamesonii via ovule culture: influence of fall versus spring sampling on callus formation and shoot regeneration

The unfertilized ovules of one clone of Gerbera jamesonii H. Bolus ex Hook. f. were cultured in vitro as a means of producing haploid plants. A total of 4715 ovules were cultivated on 17 media during two distinct periods of the year. All the media tested, except the ones containing 0.5% w/v of activated charcoal, were able to sustain the formation of callus. When these calli were transferred to the regeneration medium, shoot differentiation occurred in about 2 weeks. Usually, callus induction occurred at a higher frequency during the fall experiments. However, the calli produced in the spring displayed a higher morphogenetic capacity. Chromosome and chloroplast counts performed on randomly selected plants revealed that 76% of the regenerants were haploid and 24% were diploid.

In vitro induction of haploid plants from unpollinated ovules and ovaries of the sugarbeet (Beta vulgaris L.)

Haploid plantlets from male fertile and male sterile sugarbeet plants could be induced at frequencies up to 2.2% using ovule culture. Ovary culture on media without charcoal resulted in a similar induction frequency. Plant development was inhibited by callus development originating from the mother tissue. When the callus parts were removed and the ovule transferred to a new medium without 2,4 D, callus formation could be inhibited by adding 0.5% charcoal to the medium. Up to 6.1% haploids were induced. Chromosome counts in leaf tips, chloroplast counts and isozyme patterns revealed that all plants were haploid and originated from the haploid cells of the embryo sac. Root tips showed spontaneous polyploidisation.

Indirect selection criteria for isolation of induced polyploids in the Abelmoschus species hybrids.

Three interspecific hybrids of Abelmoschus, viz., A. esculentus×A. tetraphyllus, A. esculentus×manihot and A. esculentus×A. manihot ssp. manihot, and their colchiploids were compared for stomatal length and frequency, frequency of stomatal chloroplasts and pollen diameter. Significant increase in stomatal length and frequency of stomatal chloroplasts and significant decrease in frequency of stomata per unit area were observed in polyploids as compared to the respective F1 hybrids with no overlapping. Frequency distribution for pollen diameter of the polyploids revealed a considerable overlapping though the differences were significant. Stomatal chloroplast count can be used as a reliable technique for identifying induced polyploids in Abelmoschus species.

The production of homozygous diploid plants of Solanum verrucosum by tissue culture techniques

Monohaploid plants of S. verrucosum (2n=x=12) were induced in anther culture. Axillary buds from these plants were treated with colchicine in shoot tip culture for 48 hours and then transferred to a colchicine free medium. The resulting plantlets were scored for diploidy by stomatal chloroplast counts and root tip cytology and it was found that doubling of the chromosome number had occurred.

Stomatal chloroplast number in diploids and polyploids ofGossypium

Stomatal chloroplast count technique as a tool to identify the ploidy status was evaluated in species, hybrids and polyploids (natural and induced) involving the A, B and D genomes inGossypium. The differences between group means were significant. Intra group differences were significant for diploids and hexaploids but this was not due to the genomes involved. Thus some varieties of diploids,G. arboreum (A 2) were on par withG. raimondii (D5). The percentage increase in chloroplast number per stoma was 25 for triploids, 72 for tetraploids and 102 for hexaploids taking the diploid number as the base. Ploidyper se had great impact on chloroplast number. It appears that stomatal chloroplast count technique can be used as a rapid method to identify polyploids in the genusGossypium.

Identification of Cotton Haploids by Stomatal Chloroplast‐count Technique1

Chloroplast counts were made from the stomatal guard cells in haploid (n = 2x = 26) and in natural tetraploid (2n = 4x = 52) plants of Gossypium hirsutum L. and G. barbadense L. The mean chloroplast number was 10.46 ± 2.18 for haploids and 21.00 ± 3.31 for tetraploids. The means from haploid plants did not overlap with the means from tetraploid plants in 280 plants evaluated. Cotton plants can be classified much easier and quicker from the cotyledon stage to maturity as haploids or tetraploids and as accurately as by chromosome counts.

1. 葉緑体数によるてん菜倍数性の簡易検定 : 葉緑体数の2品種間差異(談話会年次講演会講演要旨昭和36年度)

1. 葉緑体数によるてん菜倍数性の簡易検定 : 葉緑体数の2品種間差異(談話会年次講演会講演要旨昭和36年度)

Chloroplast Number in Leaves of Normal Wheat Plants and Those Infested with Hessian Fly or Treated with Maleic Hydrazide12

Chloroplasts were counted in leaves of normal wheat plants, those infested with hessian fly(Phytophaga destructor (Say)), and those treated with maleic hydrazide. The chloroplast number decreased in the outer leaves and increased in the inner leaves of the treated plants. In the hessian fly infested wheat plants, the chloroplast counts increased in both inner and outer leaves over those of the normal plants. It appeared that the dark-green color of the inner leaves of hessian fly infested wheat was due to increased chloroplast numbers. It appeared further that the dark-green color of the outer leaves of maleic hydrazide treated plants was due to a greater concentration of chlorophyll per chloroplast.