I2-KI Solution Research Articles

Optimization of acquisition parameters of slurry coating characteristics based on multiple yarn simultaneous detection

A simultaneous detection method was proposed to detect slurry coating characteristics based on the same spatial resolution of starch-based sized and raw yarns. A dynamic image acquisition device was improved to capture the apparent images of multiple yarns simultaneously after the starch–iodine color reaction. The slurry coating characteristics were calculated utilizing image-processing technology. For the sake of effective and stable detection, the effects of illumination conditions on the concentration of I2-KI solution were studied through the absorbance value test. The effects of image-processing parameters on the experimental results were analyzed respectively by measuring six kinds of yarn of different counts and size pick-up. The results showed that the illumination conditions within an illumination time of 0–60 min, illumination intensity of 0–80,000 lux and illumination distance of 0.01–0.20 m had no significant effects on the concentration of I2-KI solution. Eight rows of pixels in the central axis areas of the yarn were determined as the effective statistical areas. It was determined that the sample size can meet the needs of stability test in 200 pieces. A dynamic threshold method, which served the intersection of the gray histogram of sized and raw yarn under the same spatial resolution as the threshold, can effectively segment the slurry coating areas. On the above basis, the optimization acquisition parameters of the detection method were obtained. The proposed method can meet the requirements of the efficiency test, common applicability and ease of operation.

A novel method for evaluating the slurry coating characteristics of sized yarns based on the starch-iodine color reaction principle and image processing

The slurry coating characteristics of sized yarns directly impact warp weavability. Due to the damage to sized films, the conventional methods of detecting sized-yarn coating characteristics have drawbacks of low efficiency and poor repeatability. A novel detecting method of slurry coating characteristics was proposed based on image processing. Through the starch-iodine color reaction principle, a self-made dynamic image acquisition device was developed in this paper, in which the apparent images of starch-based sized yarns after color reaction were captured consecutively. The slurry coating percentage ( SCP), slurry coating depth ( SCD) and slurry coating unevenness ( SCU), respectively reflecting the sizing coating integrity, sizing coating thickness and thickness unevenness, were extracted by image processing. The effects of experimental parameters, including immersion time and concentration of I2-KI solution, on slurry coating characteristics were analyzed, and central composite design was adopted to optimize the stability of the test system. Sized yarns commonly used in textile mills were characterized by the proposed method. The experimental results indicated that immersion time of 3.56 min and I2-KI concentration of 0.11‱ (‱ represents that the mass of the solute is one ten-thousandth of solution) led to the optimal stability of slurry coating characteristics (the CV of SCP, CV of SCD and CV of SCU were 3.32%, 5.56% and 9.37%, respectively). The much lower CV of the proposed method compared with conventional ones confirmed that the method was useful for evaluating slurry coating characteristics.

Investigation of optimal sample preparation conditions with potassium triiodide and optimal imaging settings for microfocus computed tomography of excised cat hearts.

To determine optimal sample preparation conditions with potassium triiodide (I2KI) and optimal imaging settings for microfocus CT (micro-CT) of excised cat hearts. 7 excised hearts (weight range, 10 to 17.6 g) obtained from healthy adult cats after euthanasia by IV injection of pentobarbital sodium. Following excision, the hearts were preserved in 10% formaldehyde solution. Six hearts were immersed in 1.25% I2KI solution (n = 3) or 2.5% I2KI solution (3) for a 12-day period. Micro-CT images were acquired at time 0 (prior to iodination) then approximately every 24 and 48 hours thereafter to determine optimal sample preparation conditions (ie, immersion time and concentration of I2KI solution). Identified optimal conditions were then used to prepare the seventh heart for imaging; changes in voltage, current, exposure time, and gain on image quality were evaluated to determine optimal settings (ie, maximal signal-to-noise and contrast-to-noise ratios). Images were obtained at a voxel resolution of 30 μm. A detailed morphological assessment of the main cardiac structures of the seventh heart was then performed. Immersion in 2.5% I2KI solution for 48 hours was optimal for sample preparation. The optimal imaging conditions included a tube voltage of 100 kV, current of 150 μA, and exposure time of 354 milliseconds; scan duration was 12 minutes. Results provided an optimal micro-CT imaging protocol for excised cat hearts prepared with I2KI solution that could serve as a basis for future studies of micro-CT for high resolution 3-D imaging of cat hearts.

Augmenting Medical Neuroanatomy Cadaveric Dissection with DiceCT Imaging

Dissection of the brain and central nervous system for medical education is an informative but often wholly destructive process, leaving students with little reference material from which to review neural structures and their anatomical relationships. Here, we explore the use of diffusible iodine contrast enhancement followed by high‐resolution microCT (diceCT) to combine destructive physical dissection with more permanent digital dissection. DiceCT methods render soft tissues radiodense to X‐rays, emulating the tissue discrimination of magnetic resonance imaging (MRI). Such imaging studies provide students the opportunity to identify and interpret pathological findings in ex‐vivo neural tissues. To identify best‐practices for incorporating diceCT imaging into the medical neuroanatomy lab, we stained formalin‐preserved human brains with three concentrations of iodine (3, 4, and 5% aqueous I2KI) for 3 weeks, replacing the iodine solutions after the first and second weeks. All brains were microCT scanned at 63‐micron resolution, and the resulting image stack was rendered in Avizo version 2019.2. The stained brains were then bisected, and one hemisphere was de‐stained for 4 weeks by alternating baths of 1% sodium thiosulfate with deionized water each on a week‐long cycle. All concentrations of iodine were effectively de‐stained using this protocol. Students then performed comparative physical dissections on never‐stained, stained only, and stained‐then‐de‐stained brains, and comparative digital dissections were performed on brains of each iodine concentration. In physical dissection, stained only brains had few advantages—although the dark iodine stain enhanced some fiber tracts, specimens were smaller, physically difficult to manipulate, and harbored subcortical nuclei (e.g. the basal ganglia) that were more difficult to identify. Dissection of never‐stained and de‐stained brains was found to be equivocal, with de‐stained brains regaining much of their original size. In digital dissection, the 5% aqueous I2KI solution provided the clearest discrimination between structures, and pathologies such as age‐related atrophy and hydrocephalus were apparent. In addition to leaving a more permanent imaging study record of nervous tissue specimens, digital dissection allows for 3D printing of brain regions. These benefits were positively received by students, and we recommend incorporation of rapid, inexpensive tissue staining and tomography to enhance participation and clinical skills in the anatomy lab.Support or Funding InformationFederal Work Study, OSU Center for Health Sciences

LSSR1 facilitates seed setting rate by promoting fertilization in rice

Seed setting rate is one of the major components that determine rice (Oryza sativa L.) yield. Successful fertilization is necessary for normal seed setting. However, little is known about the molecular mechanisms governing this process. In this study, we report a novel rice gene, LOW SEED SETTING RATE1 (LSSR1), which regulates the seed setting rate by facilitating rice fertilization. LSSR1 encodes a putative GH5 cellulase, which is highly conserved in plants. LSSR1 is predominantly expressed in anthers during the microsporogenesis stage, and its encoded protein contains a signal peptide at the N-terminal, which may be a secretory protein that stores in pollen grains and functions during rice fertilization. To explore the physiological function of LSSR1 in rice, loss-of-function mutants of LSSR1 were created through the CRISPR-Cas9 system, which showed a significant decrease in rice seed setting rate. However, the morphology of the vegetative and reproductive organs appears normal in lssr1 mutant lines. In addition, lssr1 pollen grains could be normally stained by I2-KI solution. Cytological results demonstrate that the blockage of fertilization mostly accounted for the low seed setting rate in lssr1 mutant lines, which was most likely caused by abnormal pollen grain germination, failed pollen tube penetration, and retarded pollen tube elongation. Together, our results suggest that LSSR1 plays an important role in rice fertilization, which in turn is vital for maintaining rice seed setting rate.

Towards effective and stable probiotics.

Probiotics are live microorganisms, generally either lactobacilli or bifidobacteria, which when administered in adequate amounts confer a health benefit to the host [1]. Due to the growing evidence of health benefits associated with their use, probiotics are of increasing interest and represent now a significant growth area in the functional foods industry [2]. However, to be effective, orally administered probiotics should survive preparation of dosage forms and passage through acidic environment of the gastrointestinal tract (GIT). Reaching the intestine, these microorganisms should be able to establish themselves, remain viable and perform their beneficial actions. In this context, oral formulations have to protect probiotic bacteria from gastric acidity and delay their release in the small intestine in order to allow their complete release in the colon. To evaluate effects of starch formulations of lactobacilli on their survival in gastric environment and probiotic properties. Nineteen Lactobacillus strains belonging to the species L. fermentum (14 strains), L. plantarum (4 strains), and L. rhamnosus (1 strain), were isolated from dairy products and probiotics, and were used in this study. Lactobacilli were cultured in de Man, Rogosa, Sharpe (MRS) broth (Merck, Germany) under microaerobic conditions at 37°C.Amylolytic activity of lactobacilli, cultured for 3-5 days on MRS agar supplemented with 1% soluble potato starch (SPS), was determined with iodine reagent (0.01 M I2-KI solution).Loading in starch was performed with L. plantarum 8PA3 bacteria ("Dry lactobacterin", Perm, Russia), which were resuspended to the concentration 1010 cells/mL in 10 mL of 0.85% NaCl solution and added to 90 mL of 2.5% SPS solution. Resulting mixture was frozen at -18°C and then lyophilized (Martin Christ Alpha 1-2 LDplus, Germany).Atomic force microscopy (AFM) images of formulated L. plantarum 8PA3 cells were acquired in air by a Solver P47H atomic force microscope (NT-MDT, Moscow, Russia).Starch swelling and dissolution was studied in simulated colonic fluid (SCF), prepared according to [3] and in distilled water (pH = 6.0) as control. Amylase from Aspergillus oryzae (A8220, Sigma) was added to the solutions to study the influence of amylase. The formulation form was examined visually during 14 h incubation time.Fluorescence microscopy images were obtained with a Leica DM6000B (Germany) fluorescent microscope using Leica FW4000 software.L. plantarum 8PA3 loaded in SPS were placed either in HCl solution (pH 2), or in 2% oxgall bile solution, or in 0.85% NaCl solution. Viability was tested after 2, 4 and 6 h incubation at 37°C by plating diluted aliquots onto MRS agar with subsequent counting of bacterial colony forming units (CFU). In addition, viability was determined using LIVE/DEAD BacLight bacterial viability kit L-7012 (Molecular Probes, Invitrogen) as described elsewhere [4]. Fluorescence in the stained samples was estimated with BD FACS Canto II (USA) flow cytometer or fluorescent microscope.Nitric oxide (NO) production was assessed with DAF-FM DA and DAA fluorescent dyes as described earlier [4]. Each experiment was performed in triplicate. In the present study we studied the probiotic composition comprising of SPS and bacteria L. plantarum 8PA3. We used AFM to confirm effective fixation of the cells to carbohydrate. The compositions were found to swell quickly (~5 min) in aqueous solutions either containing amylase, or not. Tested starch formulations disintegrated during the first 5-10 min of incubation in amylase solutions whereas in amylase-free probes dissolution was less intensive (after ~30 min). Amylolysis of starch excipients was less pronounced in aqueous amylase solution than in SCF, supplemented with amylase. None of 19 studied Lactobacillus strains hydrolyzed SPS when growing on MRS agar supplemented with it. The amount of viable L. plantarum 8PA3 cells formulated with SPS was high and did not change when stored for 6 months at 4°C. The bacterial viability tests also demonstrated that after 6 h treatment with 2% bile or HCl (pH 2) L. plantarum 8PA3 exhibited increased sensitivity (viability 14% and 0.4%, respectively). However, in similar conditions no significant differences were noticed between bacterial viability obtained for formulated with starch and non-formulated bacteria. Furthermore, we showed that loading into SPS had no effect on bacterial production of nitric oxide (NO) - a pluripotent regulatory molecule in human organism. Overall, the results strongly support that formulation with polymeric matrices on the basis of SPS represent an appealing technology of probiotics production. It provides slow release of bacteria in target environment and does not alter their viability and NO biosynthesis. However, SPS excipient does not preserve the bacteria from harsh conditions of upper GIT. Therefore, we conclude that for oral administration the composition should be loaded in acid-resistant capsules.

Concentration‐dependent specimen shrinkage in iodine‐enhanced microCT

Iodine potassium iodide (I2 KI) solution can be employed as a contrast agent for the visualisation of soft tissue structures in micro-computed tomography studies. This technique provides high resolution images of soft tissue non-destructively but initial studies suggest that the stain can cause substantial specimen shrinkage. The degree of specimen shrinkage, and potential deformation, is an important consideration when using the data for morphological studies. Here we quantify the macroscopic volume changes in mouse skeletal muscle, cardiac muscle and cerebellum as a result of immersion in the common fixatives 10% phosphate-buffered formal saline, 70% ethanol and 3% glutaraldehyde, compared with I2 KI staining solution at concentrations of 2, 6, 10 and 20%. Immersion in the I2 KI solution resulted in dramatic changes of tissue volume, which were far larger than the shrinkage from formalin fixation alone. The degree of macroscopic change was most dependent upon the I2 KI concentration, with severe shrinkage of 70% seen in solutions of 20% I2 KI after 14days' incubation. When using this technique care needs to be taken to use the lowest concentration that will give adequate contrast to minimise artefacts due to shrinkage.

Development of Near-isogenic Lines with Different Wheat Wx Genes and Their Effects on Amylose Content and Noodle Quality

为明确不同 Wx 基因对小麦直链淀粉含量的影响以及筛选面条品质优异的基因型，以糯小麦品系Caiwx (aabbdd)为3个 Wx 基因隐性突变供体亲本，以扬麦01-2 (AABBDD)为轮回亲本，利用连续回交结合花粉碘染、STS标记和同工酶标记检测方法，创制了8种 Wx 基因纯合基因型的近等基因系，其基因型分别为AABBDD、AABBdd、AAbbDD、AAbbdd、aaBBDD、aaBBdd、aabbDD和aabbdd。利用这些基因型探讨了不同 Wx 基因对直链淀粉含量及面条感官品质的影响。结果表明，各系的直链淀粉含量为0.9%~24.8%，系间差异显著；糯小麦型(aabbdd)直链淀粉含量最低，双缺失型和单缺失型其次，双缺失型中aaBBdd型含量最高，单缺失型中AAbbDD型含量最低，表明 Wx - B1 对直链淀粉的合成作用最大。糯小麦型面条的色泽、表观、软硬度、黏性、韧性得分以及总分显著低于其他类型及轮回亲本扬麦01-2；单缺失型面条的色泽、表观得分、总分显著高于轮回亲本扬麦01-2，其中aaBBDD型面条品质表现突出，与市售优质面条粉“雪花粉”制作的面条得分相当，而其他7种基因型及轮回亲本扬麦01-2的面条评分均显著低于雪花粉。说明可以通过遗传操作 Wx 基因培育优质面条小麦品种。

Genetic Analysis and Molecular Mapping of a Male Sterile Mutant in Rice

Male sterility is an important inheritance phenomenon in plants and widely used in hybrid seed production. The male sterile plant can't produce normal male gametophyte for reproduction, while the female counterpart is normal. So far, more than 100 of male sterile mutants or genes have been reported in rice. Ms-np is a male-sterile mutant derived from a spontaneous muta- tion. The filaments of the mutant are long and thin, and the withered anthers are white and transparent. Ms-np was confirmed to be a none-pollen type mutant of male sterility, for no pollen grains were stained with I2-KI solution and the anther locules were al- ways hollow. Genetic analysis of five F2 populations and two BC1F1 populations revealed that the mutation was controlled by a single recessive gene. To uncover the molecular basis of ms-np, the F2 population derived from the cross of ms-np/M63 was used for genetic mapping. Screening of 227 F2 mutant individuals with simple sequence repeat (SSR) markers indicated that ms-np(t) was located between the molecular markers RM541 and RM343, on chromosome 6, with the distances of 15.2 and 7.9 cM, re- spectively. The results provide a basis for further gene cloning and understanding of the molecular mechanism underlying rice male fertility.

Preferential reproduction mode of hermaphrodite papaya plant (Carica papaya L; Caricaceae)

This research was done to study the reproductive system of papaya hermaphrodite plant based on the histochemical nature of pollen grain, stigma receptivity, in vivo pollen grain germination and pollen:ovule ratio. In the histochemical analysis, pollen grains were stained by using Sudan IV and I2KI solution ; the stigma receptivity was assessed by alpha-naphthtyl acetate solution in closed and opened flowers. Pollen germination and pollen tube growing were examined in flower buds near anthesis with 0.1% aniline blue. To estimate the pollen:ovule ratio , anthers from each flower bud were dissected and all pollen grains were counted; ovules were dissected from ovaries and were counted under stereomicroscope. The results indicated that papaya pollen grains are of lipidic nature; the stigmas were receptive before the opening and until 48 hours after opening; the pollen grains germinated and emitted polinic tube before flower opening and the pollen:ovule ratio indicated the predominance of autogamous reproductive system. These results indicate that hermaphrodite papaya trees is preferentially of optional autogamous with cleistogamy.

Influence of an iodine treatment on the structure and physical properties of Bombyx mori silk fibroin fiber

AbstractSilk fibroin (SF) fiber from the Bombyx mori silkworm was treated with a 1.23 N iodine/potassium iodide (I2–KI) aqueous solution, and the structure and physical properties were investigated to elucidate the effects of the iodine treatment. The SF fiber absorbed polyiodide ions such as I and I by immersion in the I2–KI solution, and the weight gain of the SF fiber increased with the treatment time; it became saturated at about 20 wt % after 40 h. The results of the weight gain, Fourier transform infrared spectroscopy, and X‐ray diffraction measurements suggested that polyiodide ions mainly entered the amorphous region. Moreover, a new sharp reflection in the meridional direction, corresponding to a period of 7.0 Å, was observed and indicated the possibility of the formation of a mesophase structure of β‐conformation chains. Dynamic viscoelastic measurements showed that the molecular motion of the crystalline regions at about 220 °C was enhanced and shifted to lower temperature by the introduction of polyiodide ions. This indicated that the iodine component weakened the hydrogen bonding between the SF molecules forming the β‐sheet structure and caused molecular motion of the crystal to occur more easily with heating. With heating above 270 °C, the iodine component introduced intermolecular crosslinking to SF, and the melt flow of the sample was inhibited. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3418–3426, 2006

Conductivity studies of poly (vinyl alcohol)-iodine complex membrane

The conductivities of polymers like poly (vinyl alcohol) (PVA) and its iodine complex membranes are reported here. PVA-iodine complex membrane was prepared by dipping PVA film into an I2–KI solution. The formation of the complex membrane was confirmed by IR spectra. Conductivities were determined from 30 to 300 °C with a frequency ranges from 42 Hz to 500 KHz in solid state. It was observed that iodine is known to act as a catalyst for dehydration of PVA. A possible mechanism for the dehydration of PVA catalyzed by iodine is also explained.

Introduction of copper iodide fine particles into a poly(acrylic acid) matrix via a complex of polymer–polyiodide ions

In this study, an organic–inorganic nanocomposite material of cross-linked poly(acrylic acid) (PAA) doped with fine particles of copper iodide (CuI) was prepared. The preparation method of the composite involved the complexing of PAA film with polyiodide ions such as I3− and I5− by immersion in an iodine–potassium iodide (I2–KI) aqueous solution, and then reaction with CuCl in aqueous hydrochloric acid, resulting in the in-situ formation of CuI fine particles within the PAA matrix. The crystal form of CuI in the composite was identified as γ-CuI using X-ray diffraction, and the amount of CuI could be varied by changing both the concentration of the I2–KI solution and the frequency of performing the doping procedure to introduce CuI into the matrix. This preparation method, using polyiodide ions as a precursor, has an advantage in that a large amount of metal iodide, such as CuI, can be easily formed, and it is regarded as a unique method for the preparation of organic–inorganic composites.

Effect of temperature on the starch content of potato callus tissue

Starch content was determined in Lemhi Russet callus grown on MS medium for 2 and 4 weeks at 25, 15, and 5°C with 50 μM 2,4-D or 10 μM picloram as the only plant growth regulator. A treatment of 5°C for 4 weeks followed by 25°C for 2 and 4 weeks was included to simulate reconditioning. Callus starch content ranged from 0.01 to 0.08% on a wet weight basis and 0.5 to 4.0% on a dry weight basis. Starch content was highest after 2 weeks at 25 and 15°C and decreased with time in a similar manner at both 25 and 15°C. Starch content decreased at 5°C, then increased significantly during simulated reconditioning at 25°C. Starch content was higher in callus grown with 50 μM 2,4-D than in callus grown with 10 μM picloram. After staining the callus with I2-KI solution, starch granule formation was observed in the callus grown with 50 μM 2,4-D, while little granule formation was observed in the callus grown with 10 μM picloram.

Promotion of flowering and seed germination in Chinese arrowhead (Sagittaria trifolia var. edulis (Sieb.) Ohwi).

Two cultivars, 'Aokuwai' and 'Shirokuwai', of Chinese arrowhead, Sagittaria tnfolia var. edulis (SIEB.) OHWI, were treated with solutions of 30 and 300ppm of gibberellic acid (GA3) to promote the production of inflorescences. Inflorescences were induced in both cultivars by the GA3 treatments as well as in the control in the case of 'Shirokuwai'. The inflorescence consisted of a raceme or compound raceme. Flowering in the GA3-treated 'Aokuwai' began six weeks after planting while seven weeks in 'Shirokuwai'. However, in the control plants flowering started 21 weeks after planting. The percentage of plants with racemes and the number of racemes per plant were higher for the 300ppm treatment than for the 30ppm one. The length of the flower stalks and racemes, and number of male and female flowers per raceme varied among the treatments. The flowers were complete and the pollen stainability rate with an I2-KI solution exceeded 90% in the 300ppm treatment in the two cultivars. Many fertile seeds were produced by open pollination. Based on the results obtained, it was concluded that the GA3 treatment at 300ppm was more effective in promoting the production of inflorescences as well as the production of fertlle pollen and seeds in Chinese arrowhead than that at 30ppm GA3. The seeds displayed dormancy, which was broken by field storage for two months. Seed germination was promoted in the light compared with darkness. These findings may contribute to the development of methods for cross-breeding of Chinese arrowhead.

Meiotic behaviour of extra chromosomes in fertility restored Polima CMS Brassica napus plants

Crosses were made between Brassica napus (2n = 38) with the 'Polima' cytoplasmic male sterile system and variety 'Zem' of B. juncea. Fertility was partially restored in backcross progeny with an extra chromosome (2n = 39) that was believed to be a member of the B genome of B. juncea. Among more than 40 self-pollinated offspring plants studied, fertility restoration was transmitted only through those plants with two extra chromosomes (2n = 40). Anthers of these plants were either full or shriveled with small swollen protrusions. Full and round pollen grains were found in full anthers and in the swollen portion of shriveled anthers. These pollen grains were stained darkly with I2-KI solution and full seed set was obtained from bagged flowers. Meiotic studies in plants with 2n = 40 showed 18 bivalents + 1 quadrivalent at diakinesis in most of the pollen mother cells analyzed. The chromosomes segregated equally at anaphase I and behaved normally at other meiotic stages. The presence of a single quadrivalent in the backcross progeny was highly consistent and occurred in very high frequencies. It is believed that the extra chromosomes belong to the B genome of B. juncea and take part in the quadrivalent formation.Key words: Brassica napus, cytoplasmic male sterility, aneuploidy, Polima, Brassica juncea, rapeseed cytogenetics.

Rapid estimation of the amylose/amylopectin ratio in small amounts of tuber and leaf tissue of the potato

Small amounts of potato tuber and leaf tissues are extracted in perchloric acid. After staining with I2-KI solution absorbancies at 618 and 550 nm are measured. The amylose/amylopectin ratio can be estimated from the ratio of the absorbancies by using a formula or a graph in which the specific absorptions of the two compounds are introduced. Weighing of samples is not required. The method can be used for the estimation of the starch composition of minitubers and is especially suitable for the detection of mutants with an altered starch composition.

A cytogenetic study of monosomics in Brassica napus L.

Two types of monosomic plants of Brassica napus L. were discovered among the backcross progenies of crosses between Diplotaxis muralis L. and B. napus and between Brassica juncea L. and B. napus. These monosomics were designated mono-1 and mono-2, respectively. Morphologically the monosomic plants were virtually indistinguishable from their sib disomic plants. Seed production on both mono-1 and mono-2 plants was normal. Cytological examination revealed that most pollen mother cells (85%) of mono-1 plants formed 18 bivalents plus one univalent at diakinesis, while the remainder (15%) formed 17 bivalents plus a trivalent. The univaltn in mono-1 was submetacentric and its two arms were always stained more lightly than the centromeric region. Later meiotic stages in mono-1 plants appeared normal. The plants of mono-1 produced two types of pollen grains which were different in size. Both the large and small pollen grains of mono-1 were deeply stained with an I2–KI solution. Meiotic behavior of mono-2 plants was similar to that of mono-1 plants, but the frequency of trivalent formation was higher (62%). The univalent in mono-2 was longer than the two chromosomes it paired with to form a trivalent. Pollen produced on mono-2 plants was uniform in size and comparable to that of the normal disomics.Key words: Brassica napus, Brassica juncea, Diplotaxis muralis, aneuploidy, monosomics.

Interspecific cytoplasm substitutions of an Indica strain of Oryza sativa L. and O. Glaberrima Steud

To study differential nucleus-cytoplasm interactions between the two cultivated rice species, Oryza sativa and O. glaberrima, cytoplasmic substitution lines were made by using a glaberrima strain (G) and an Indica strain of sativa (S). The G cytoplasm had no adverse effect on pollen development when combined with the nucleus of S. On the other hand, when the S cytoplasm was combined with the G nucleus, the substitution line showed no seed set because of male sterility although the pollen grains were normally stained with I2-KI solution. A dominant gene derived from S strain seemed to cause anther indehiscence in the substitution line. Further, a restorer gene (Rf j)from Akebono of Japonica type was effective on pollen restoration in the male sterile line, suggesting that the S cytoplasm is the same as those of Japonica type in terms of a fertility-restoring system.

Sorption and permeation of iodine in water‐swollen poly(vinyl alcohol) membranes and iodine complex formation

AbstractThe sorption and the permeation of iodine in water‐swollen poly(vinyl alcohol) (PVA) membranes and the formation of PVA–iodine complexes were studied. The logarithms of the permeability and the diffusion coefficient decreased approximately linearly with the increase in polymer volume fraction. When the membrane was soaked in an aqueous I2–KI solution, it contracted and Young's modulus increased. These findings were explained in terms of the formation of extra junction points due to the PVA–iodine complexes. These changes were reversible and could be recovered by replacing the solution with water. The length of the polyiodine chain increased with the increase in the degree of hydration of the membrane. At a fixed degree of hydration, Young's modulus of an iodine‐sorbed membrane was much greater than that of a membrane soaked in pure water. This finding was explained on the basis of a double‐network structure. The extension of the membrane promoted the complex formation, and the complex disappeared when the tension was released. The critical strain necessary for the complex formation was independent of the degree of hydration. The length of polyiodine chain increased with strain and became constant at higher strains.