Gayle Davidonis

Callus formation and shoot regeneration in vanilla planifolia

Abstract The high demand for natural vanilla flavor led to attempts to establish an in vitro cell culture of Vanilla planifolia for flavor production and for shoot regeneration from callus. Explants from Vanilla planifolia shoots were placed on supplement Murashige and Skoog salts and tested for callus formation. Callus formation could be achieved with various media. Shoots could be regenerated from callus under various concentrations of a‐naphthaleneacetic acid (NAA) and benzyladenine (BA). The first node was the best location for callus initiation with subsequent callus proliferation.

Influence of seed location on cotton fiber development in planta and in vitro

A number of different levels of competition for resources have been described that influence cotton (Gossypium hirsutum L.) fiber quality. These include the number of bolls on a fruiting branch, and on a secondary level, the location of seeds within a locule. Cotton ovule culture was employed to assess the contribution of competition for resources to fiber quality. Elongation and secondary wall deposition were compared in plant-grown and culture-grown fibers. In plant-grown material, seeds located in the middle of a locule had the longest fibers. Fiber length distributions were similar for ovules taken from the apical, medial and basal locations in a locule and grown in ovule culture. Secondary wall deposition was greatest in fibers located on basal seeds or ovules. On a single seed or ovule, fibers in the micropylar region had thicker cell walls than in the chalazal region. Competition for resources has been eliminated in vitro and the same pattern of secondary wall deposition occurred in the micropylar and chalazal regions of seeds and ovules. Therefore, conditions present at the time of ovule excision influenced secondary wall deposition. One condition may be fiber diameter.

Applications of AFIS fineness and maturity module and x-ray fluorescence spectroscopy in fiber maturity evaluation

Worldwide round-testing and calibration of the nep-counting and fiber-length mod ules of the Zellweger Uster advanced fiber information system (AFIS) are well advanced. Lack of appropriate quantitative calibration standards for fiber maturity has limited similar development of the prototypic AFIS fineness and maturity (F&M) module. A combination of calcium x-ray fluorescence Spectroscopy (Ca-XRF) and AFIS-F&M map ping of fiber quality from twenty-one days post anthesis (DPA) to boll opening (56 DPA) permits direct comparisons of AFIS-determined fiber physical maturity (as micronAFIS, circularity, and cross-sectional area) with fiber chronological maturity (as DPA) and physiochemical maturity (as Ca-XRF). The AFIS-F&M module is a powerful tool that makes possible quantitative comparisons of fiber maturity across time (during fiber development and in different crop years), across space (different boll and locule positions and different growing areas), within single bolls and locules, and between cotton varieties and species.

Near Infrared Measurement of Cotton Fiber Micronaire, Maturity and Fineness - a Comparative Investigation

A key cotton fiber quality property is micronaire, which acts as an indicator of the fiber’s maturity and fineness. Previous studies have demonstrated the ability of Near Infrared (NIR) instrumentation to measure these cotton properties with varying degrees of success, but these studies did not provide conclusions on the capabilities of NIR spectroscopy as a general technique for these analyses. Recent advances in NIR technology could result in improved measurements of these cotton properties. A comparative investigation was implemented to determine the capabilities of modern commercial bench-top and portable NIR systems to monitor cotton fiber micronaire, maturity, and fineness in order to gain insight as to the “universality” of the NIR measurements for these fiber properties. Cotton samples were analyzed on five commercial systems and an older, custom-built system. Very good spectral agreement was observed between the portable and bench-top NIR units. The rapid and simultaneous measurement of cotton micronaire, maturity, and fineness by multiple commercial systems was demonstrated and compared favorably to the custom system, but without the delay and cost in building custom units. For the bench-top NIR systems, all end-state criteria were successfully meet. The “universal” nature of the NIR measurement of these cotton fiber properties was validated for commercial NIR systems. As expected, the NIR results for the portable NIR units were normally not as good as those for the bench-top instruments, but they were very acceptable for demonstrating the potential for the portable units to measure these cotton fiber properties.

Influence of low-weight seeds and motes on the fiber properties of other cotton seeds

Abstract Suboptimal growth conditions can hinder cotton fiber growth and development. Bolls were selected from cotton plants ( Gossypium hirsutum L.; Deltapine 50, 51) grown in Texas over a 3 yr period. Fiber samples from seeds located in the middle of the boll were analyzed using the advanced fiber information system (AFIS). Motes are developmentally arrested seeds and their associated fiber. By definition, motes cannot germinate. Motes were divided into two categories — short-fiber and long-fiber — where fiber from long-fiber motes was one half the length of fibers on normal seeds. Large numbers of short-fiber motes per boll did not have a detrimental effect on the fiber quality of the middle seeds in a boll. Large numbers of long-fiber motes per boll reduced the extent of secondary wall deposition in fibers from middle seeds, while small numbers of low-weight seeds or long-fiber motes per boll did not affect the fiber quality of middle seeds. The identification of sources of poor quality fiber facilitates prediction of dyeing irregularities ultimately benefiting producers, processors and consumers.

Gibberellic acid-induced cell elongation in cotton suspension cultures.

Gibberellic acid (GA3) causes cell elongation in cotton suspension cultures derived from cotton ovule callus tissue of both auxin-dependent and-independent lines. Cell elongation was more pronounced in auxin-dependent cultures. Cells were cultured for a period of 14 days but differences in cell lengths could be detected after 6 days in culture. Cell elongation took place in cultures in which GA3 was present throughout the culture period or only for the first 3 days. Auxins and cytokinin alone or in the presence of GA3 did not promote cotton cell elongation above the value for the treatment with GA3 alone.

Biased Experimental Fineness and Maturity Results

In an earlier paper, we developed models and performed computer simulations to understand the variability in coefficients of determination (R2) between fineness and maturity, micronaire and fineness, and micronaire and maturity of cotton. We subsequently concentrated on derivation and testing of several diagnostic models to enhance the R2 and provide information about the analytical quality (accuracy) of the results. We then introduced modeling of biased fineness and maturity results. Error functions were derived based on micronaire values, specifically, Lords micronaire model. This paper demonstrates testing of a key diagnostic model on two different sample sets of 21 cottons. The results from one sample set — analyzed on the fineness and maturity tester — fit the model. Results from the other sample set — analyzed on both the advanced fiber information system (AFIS) A-2 and AFISPRO — demonstrate a lack of fit to the diagnostic model. This lack of fit is due to bias in the AFIS fineness and maturity measurements compared to the more traditional Lords micronaire model. As a consequence of the bias, the dynamic range of the AFIS raw data for both fineness and maturity is very narrow. Results are confirmed by image analysis.

A comparison of cotton ovule and cotton cell suspension cultures : response to gibberellic acid and 2-chloroethylphosphonic acid

Summary * Cotton ovule cultures have proved to be useful tools in the elucidation of the fiber growth parameters that ultimately affect fiber quality. Ovules pretreated with chloroethylphosphonic acid (CEPA) or gibberellic acid (GA 3 ) were subsequently placed in media containing GA 3 . Fiber elongation was inhibited on ovules pretreated for 20 h with CEPA. Ovules exposed to GA 3 in a 16-h pretreatment, followed by culture in 100 μM CEPA. 5.7 μM GA 3 + 100 μM CEPA, or 5.7μM GA 3 , 5μM IAA + 100 μM CEPA exhibited inhibition of fiber elongation. Inhibition was least on fibers receiving a GA 3 , IAA + CEPA treatment. A simultaneous addition of 5.7μM GA 3 and 100 μM CEPA inhibited fiber elongation. In cotton cell suspension cultures, cell elongation was inhibited and lateral cell expansion was promoted in GA 3 + CEPA-treated cultures. Cotton ovule cultures were less sensitive to CEPA than cotton cell suspension cultures.

The Cotton Fiber Property Variability Continuum from Motes Through Seeds

Cotton fiber quality at the bale level is a composite of all the constitutive fibers in the bale. Bales contain fibers from both mature seeds and motes (developmentally arrested seeds). The degree of variability shown in the fiber properties of seeds and motes serves as an indicator of the amount of variability in a bale. Cotton (Gossyium hirsutum L.) has been collected from machine harvested fields, and fibers have been removed by hand or ginned with a small laboratory saw gin and analyzed with the Zellweger-Uster advanced fiber information system (AFIS). Distribution of ginned mote and seed weights are similar for three cotton varieties, but composite fiber properties are different. Early termination of embryo growth results in short-fiber motes. The degree of secondary wall deposition for short-fiber motes shows that the capacity for cell wall synthesis is not terminated with the termination of embryo growth. Cotton samples are categorized by ginned mote and seed weights. The cotton varieties with the most mature fibers also have the most mature mote fibers. As ginned seed weight increases, fiber maturity increases. Fiber perimeter values fluctuate for motes but remain constant once a ginned seed weight of 56 mg is reached.

Changes in Polyamine Distribution during Cotton Fiber andSeed Development

Summary The distribution of free, conjugated and bound putrescine, and spermidine was monitored in fiber andseed of Gossypium hirsutum L. during the period from 5 to 28 d post anthesis (dpa). Fiber and seed were collected from greenhouse-grown and field-grown material. The cultivars Texas Marker 1 and Deltapine 50 were used. Fiber contained less total polyamines than seed. The highest polyamine concentration in fiber occurred at 5 dpa and in seed at 21 dpa. These peaks in total polyamine concentration correspond to the time just prior to rapid fiber elongation and the time of accelerated cell division in the embryo. A possible role of polyamines in cell elongation is discussed.