Promotive effects of organic solvents and kinetin on dark germination of lettuce seeds

Significant promotion in dark germination was observed when Grand Rapids lettuce (Lactuca sativa L.) seeds were soaked in acetone or dichloromethane, vacuum-dried, and imbibed at 25 C. Permeation of kinetin via these organic solvents further enhanced the dark germination. Those seeds that were affected by acetone and acetone-kinetin treatments and germinated in the dark escaped red-far red photocontrol of germination. Although abscisic acid was not detected in the organic solvent leachates, they did contain other inhibitory substances affecting lettuce seedling growth. In the light, acetone and acetone-kinetin treatments also enhanced the rate of germination and the increased germination by acetone-kinetin treatment was correlated with increased polyribosome formation. The possible mechanisms involved in promotion of lettuce seed germination by organic solvents and kinetin are discussed.

Changes in Isoperoxidases during Cold Treatment of Dormant Pear Embryo

The number of isoperoxidases and the intensity of certain isozymes increased with increasing periods of stratification of pear (Pyrus communis cv. Bartlett) embryos. The presence of GA(3) or kinetin during stratification enhanced the activity of certain isoperoxidases, and these enhancements were blocked in the presence of ABA which by itself had an inhibitory effect. Enhancement in isoperoxidases of pear embryos during stratification was inhibited by 6-methylpurine and cycloheximide; and in the presence of either of these two inhibitors, stratification failed to release the dormancy. Pear embryos germinated for 3 days showed changes in the pattern of isoperoxidases depending on the length of stratification.

Endogenous abscisic Acid levels in germinating and nongerminating lettuce seed

The concentrations of abscisic acid in Grand Rapids lettuce (Lactuca sativa L.) seeds imbibed under conditions which promote or inhibit germination were determined by electron capture-gas chromatography. The concentration of abscisic acid in dry seeds was 12 to 14 nanograms per 100 milligrams. During 24-hour imbibition, the abscisic acid content diminished more rapidly during conditions which allow germination (25 C in light) than in conditions which inhibited germination (35 C in light or darkness at 25 C). A decrease in endogenous levels of abscisic acid was not always correlated with germination.

Occurrence of some enzymes in starchy endosperm and hormonal regulation of isoperoxidase in aleurone of wheat

Peroxidase, indoleacetic acid-oxidase, alkaline, and acid phosphatases were detected in dry starchy endosperm (minus aleurone) of wheat grain. The isoperoxidase pattern differed in different parts of the dry grain. Several new isoperoxidases were found in embryos after soaking. The intensity of isoperoxidases in aleurones was enhanced in the presence of embryo or 2 muM GA(3) after 24 hours of soaking, but decreased after 72 hours. Indoleacetic acid and kinetin had no effect on isoperoxidase of aleurone. Actinomycin D and cycloheximide had no effect on isoperoxidases of aleurones from embryonectomized or naturally occurring embryoless grains. However, these two inhibitors increased the intensity of isoperoxidases in aleurones of intact embryonated grains after soaking.

Additive and synergistic effects of kinetin and ethrel on germination, thermodormany, and polyribosome formation in lettuce seeds

The inhibition of germination of Grand Rapids lettuce (Lactuca sativa L.) seeds at 35 C was removed to a marked extent by kinetin and 2-chloroethylphosphonic acid (ethrel). When both compounds were used together, an additive effect was observed. A synergistic effect was, however, noted when ethrel promoted the kinetin reversal of abscisic acid inhibition of seed germination (light- as well as gibberellic acid-, induced). Both kinetin and ethrel increased the total ribosomal material and the percentage of polyribosomes in lettuce seeds imbibed in the light for 24 hours. A combination of the two compounds showed a synergism in polyribosome formation only at high ethrel concentration. The inability of ethrel to reverse abscisic acid inhibition indicates that kinetin action cannot always be substituted by ethrel. The possible mechanisms involved in the enhanced response by a combination of kinetin and ethrel are discussed.

Penetration of dry seeds with chemicals applied in acetone

Acetone is able to carry chemicals through the seed coats to reach the embryo. The amount of chemical penetrating into the seeds depends on the seed type, permeation time, and the concentration of solution. The chemicals reaching the embryo are biologically effective.

Relationship of ribonucleic Acid metabolism in embryo and aleurone to alpha-amylase synthesis in barley

RNA metabolism of embryo and aleurone of barley grains (Hordeum vulgare L. cv. Himalaya) was studied to elucidate the role of these tissues in the control of alpha-amylase synthesis and germination. The extent of (3)H-uridine incorporated into various RNA classes of the embryo during the first 12 hours of germination was low but constant. Subsequently, there was a rapid increase in RNA synthesis of all fractions. In the aleurones, after 16 hours, a gradual decrease in (3)H-uridine incorporation was observed, and by the time the synthesis of RNA in the aleurones had stopped, alpha-amylase level was at its highest in the grain.On transfer to accelerated aging conditions (43 C; 85% relative humidity), the grains lost their viability within 4 weeks. That this was due to a rapid deterioration of the embryo and not of the aleurone was apparent in studies on alpha-amylase formation, RNA metabolism, and ATP content in grains in various physiological states reported here. Results presented here also reveal a marked influence of the embryo and GA(3) on the quality of the newly synthesized RNAs. Aleurones which lacked the impulse of embryo or GA(3) were capable of synthesizing RNA but these RNAs were less heterodisperse than RNAs from aleurones which were under the influence of an embryo or GA(3).

Triplets--one ectopic, two intrauterine

A case of ovarian ectopic conception, complicating a simultaneous twin intra-uterine pregnancy is described, in which the operative diagnosis was confirmed by histological examination.

Such cases are extremely rare and comment is made upon this with references.

Application of chemicals in organic solvents to dry seeds

Various chemicals were applied to dry seeds by means of organic solvents. The gibberellic acid-treated (1 mm) lettuce seeds (Lactuca sativa L.) germinated nearly 100% in the dark even after prolonged storage, and those treated with abscisic acid (1 mm or 0.5 mm) failed to germinate in the light. The seedlings emerging from morphactin-treated (1 mm) cucumber seeds (Cucumis sativus L.) exhibited profound changes in morphology. Different combinations of hormones applied to lettuce seeds caused a promotion or an inhibition of germination. Germination promotion or inhibition studies showed that the applied chemicals could be removed by washing with an organic solvent or water. Progressively larger amounts of chemicals were removed with increasing periods of washing. Thus the chemical appeared to penetrate the seed to some degree. The potential of the organic solvent method is discussed.

Embryoless Wheat Grain: A Natural System for the Study of Gibberellin-induced Enzyme Formation

Yorkstar wheat, grown in New York State, has a high percentage (10-11) of grains without embryos. The embryoless grains have viable aleurone layers and show no sign of injury. These grains are able to support alpha-amylase synthesis only in the presence of gibberellin A(3) (GA(3)). In the absence of GA(3) some protein synthesis occurs in embryoless grains during the early hours of soaking, indicating that such activity occurs prior to and independent of GA(3) induction of alpha-amylase. The level of beta-amylase on a dry weight basis is the same in embryoless and normal grains and decreases with time of soaking. In the presence of GA(3), beta-amylase decreases at a slower rate. Isoenzymes of alpha-amylase from GA(3)-treated embryoless and normal grains show quantitative as well as qualitative differences. Cycloheximide (60 mug/ml) completely inhibits the synthesis of alpha-amylase by embryoless grains. Of the RNA synthesis inhibitors, actinomycin D (60 mug/ml) was ineffective while 6-methylpurine (60 mug/ml) gave 65% inhibition without decreasing the number of isoenzymes.

Hormonal control of isoperoxidases in lentil embryonic axis

Detachment of the cotyledons from the lentil (Lens culinaris Med.) embryonic axis causes in the latter an increase in total peroxidase activity which is shown to be due to enhancement of specific cathodic isoperoxidases. Kinetin treatment of attached or detached axes promotes activity of essentially the same cathodic isoperoxidases. In addition kinetin enhances the activity of two anodic peroxidases and represses specifically that of a cathodic one. Abscisic acid inhibits the production of all isoenzymes in the presence or absence of kinetin. Cytokinin and abscisic acid actions are discussed in relation to the nature of a wounding hormone and the role of natural inhibitors in cotyledons during germination. Indoleacetic acid stimulates the activity of certain isoenzymes which are also stimulated by kinetin, whereas in others the effects of the two hormones are different. Specific inverse effects of indoleacetic acid and kinetin are demonstrated on the two most cathodic isoperoxidases. Indoleacetic acid-kinetin interactions on the cathodic isoperoxidases have been found in the literature and are discussed as a possible mechanism for explaining interactions of the two regulators on growth and other physiological processes.

Effects of the abortion law, 1967, on a gynaecological unit

In the United Kingdom the more liberal attitude towards abortions engendered by the 1967 Act has increased the work of a gynaecological unit at Salford, Lancashire, by about 10%. In 1964-65 there were 15 therapeutic abortions, and in 1969-70 the number had increased to 447. The increased demand has been catered for by a reduction of stay in gynaecological patients: in fact, the "through-put" has increased and the waiting-list diminished. The increased work-load on the blood transfusion service has been slight, and on the credit side there has been a reduction in the numbers of septic abortions. The major problem has been in the outpatient department, since these cases are time-consuming and it is difficult to make a fair and impartial decision.

Morphactin influences sexual and asexual reproduction in fungi

It has been reported that fungi are not affected morphologically by morphactins. We found, however, that levels of perithecial formation by Nectria haematococca and pycnidial formation by Ascochyta pisi were strikingly lowered by concentrations of morphactin not inhibiting or only slightly inhibiting vegetative growth. Photo- or geo-tropism of Phycomyces blakesleeanus was not affected, and there was no evidence for interference by morphactin in the light reactions stimulating perithecial production by Nectria haematococca.

Eight-Membered Cyclosilicate Rings in Muirite

The determination of the crystal structure of muirite, Ba(10)(Ca,Mn,Ti)(4)Si(8)O(24)(Cl,OH,O)(12) . 4H(2)O, revealed the presence of discrete cyclic silicate anions, (Si(8)O(24))(16-), formed by the condensation of eight silicate tetrahedra. This first reported occurrence of eight-membered rings is of particular interest, because rings with eight tetrahedra are reported to be energetically less stable than rings with six tetrahedra, which have been found in many minerals.

Selective effect of hormones on nucleic acid metabolism during germination of pear embryos

1. The effect of hormones on (32)P incorporation into various RNA fractions in germinating pear embryos was studied by fractionation on methylated albumin-kieselguhr columns. Abscisic acid inhibited labelling of soluble RNA, DNA-RNA hybrid and light-ribosomal RNA fractions with (32)P and this effect was reversed by both kinetin and gibberellic acid. 2. Kinetin reversed the inhibition by abscisic acid of (32)P incorporation into total ribosomal RNA and appeared to promote labelling of heavy-ribosomal RNA. Gibberellic acid was more active than kinetin in reversing the inhibition by abscisic acid of labelling of the DNA-RNA hybrid fraction with (32)P, but in contrast with kinetin appeared to increase further the inhibition by abscisic acid of labelling of total ribosomal RNA. 3. The percentage of radioactivity in various RNA fractions showed marked variation in response to hormones. 4. The pattern of labelling of RNA in pear embryos during reversal of inhibition by abscisic acid with a combination of kinetin and gibberellic acid was similar to that after cold-treatment of dormant pear embryos. This is suggestive of hormonal interplay in dormancy release by cold-treatment in pear embryos.