Changes In Fresh Weight Research Articles

Decline in ascorbate peroxidase activity – A prerequisite factor for tepal senescence in gladiolus

Flower senescence was studied in Gladiolus cv. "Snow Princess" over five arbitrarily divided developmental stages (stage 1, half bloom; stage 2, full bloom; stage 3, beginning of wilting; stage 4, 50% wilting; stage 5, complete wilting) in terms of changes in fresh weight, antioxidant enzymes (superoxide dismutase, SOD; ascorbate peroxidase, APX; glutathione reductase, GR) activities and membrane integrity. A significant decrease in tepal fresh weight was observed over the senescence period (after stage 2). Membrane integrity was studied by measuring lipid peroxidation [in terms of thiobarbituric acid reactive substances (TBARS) content] and membrane stability index (MSI) percentage. Maximum TBARS content was recorded in stage 4 (50% wilting). This increase in lipid peroxidation over the senescence period was in close association with high degree of membrane deterioration expressed as decrease in membrane stability index percentage. A significant decrease (two and half-fold) in MSI% in stage 5 (as compared to stage 1) indicates complete membrane deterioration. Progressive increase in endogenous H2O2 level was recorded over senescence period. Maximum H2O2 content (19.7+/-1.4 micromol g(-1) DW) was recorded at stage 5 (complete wilting). Three different patterns were observed in antioxidant enzymes behavior over the senescence period. APX activity was declined significantly as, the flower entered stage 3 (beginning of wilting) from full bloom condition (stage 2). Progressive and significant increase in SOD activity was measured as a function of time. Maximum SOD activity (24.2+/-0.8 U mg(-1) DW) was recorded in stage 5 (three-fold increase over stage 1). GR activity initially increased up to stage 4 (50% wilting) and declined significantly thereafter (approximately seven-fold). An increase in endogenous H2O2 level during senescence may be the result of a programmed down-regulation of APX enzyme activity, which seems to be the prerequisite factor for initiating senescence process in gladiolus tepal.

スイートバジルの貯蔵における抗酸化性と総フェノール量の変化

The effects of storage temperature on antioxidant activity and total phenolic content were investigated in sweet basil (Ocimum basilicum L.) leaves. Sweet basil leaves were sealed in 0.068mm polyethylene packages and stored at 3°C and 25°C. The leaves stored at 3°C exhibited a higher weight loss and severer chilling injury symptoms in the form of browning than those stored at 25°C. There were slight changes in fresh weight and leaf color during storage at 25°C. Antioxidant activity on the first day of storage decreased markedly regardless of storage temperature, and showed little correlation with total phenolic content. The respiration rate of the leaves stored at 3°C was almost twice as high as that of the leaves stored at 25°C after two days of storage. Neither of the tested storage temperatures prevented the decrease in antioxidant activity after harvest.

ON-LINE ACQUISITION OF PLANT RELATED AND ENVIRONMENTAL PARAMETERS (PLANT MONITORING) IN GERBERA: DETERMINING PLANT RESPONSES

For on-line plant monitoring equipment to be functional in commercial glasshouse horticulture, relations between sensor readings and plant responses on both the short (days) and long term (weeks) are required. For this reason, systems were installed to monitor rockwool grown gerbera plants on a minute-to-minute basis from July 2002 until April 2003. Data collected included, amongst others, crop transpiration from lysimeter data (2 m2), canopy temperature using infrared sensors, rockwool water content, and greenhouse climatic parameters, such as global radiation and temperature. By combining data from lysimeter and water content, changes in crop fresh weight could be calculated on a daily basis. Both transpiration and daily fresh weight production were better related to light integral as measured inside the greenhouse, than outside the greenhouse. The contribution of heating pipes underneath the canopy to transpiration could be estimated with the system. From the relation between daily FW production and previous day light integral, a light use efficiency of ca. 10-g FW/MJ solar radiation as measured inside the greenhouse was calculated. Water use efficiency was on average 25 g FW/L. A 3-4 day drying cycle did not affect flower production. The results underline the importance of knowledge on the adaptation and tolerance of crops to stressful conditions, in order to be able to use plant monitoring under grower conditions effectively.

Sub-picomole high-performance liquid chromatographic/mass spectrometric determination of glutathione in the maize ( Zea mays L.) kernels exposed to cadmium

Changes in fresh weight, total protein amounts (Bradford’s method), cadmium concentration (DPASV) and glutathione content (HPLC/MS) were studied in maize kernels cultivated for 5 days at three different cadmium concentrations (0, 10 and 100 μmol l −1 CdCl 2). A highly sensitive HPLC/MS method was used for the determination of glutathione on a reversed-phase Atlantis dC 18 chromatographic column ( 150 mm×2.1 mm , 3 μm particle size). An isocratic mode with acetonitrile–0.01% TFA (5:95, flow rate 0.1 ml min −1 and 30 °C) was applied. The m/ z spectra and the data for the selected ion monitoring (SIM) mode were recorded at m/ z for glutathione 308→179. Cadmium concentration was measured by a differential pulse adsorptive stripping voltammetry (DPASV) after deposition on a hanging mercury drop electrode (HMDE) at potential −0.7 V (accumulation time 180 s, acetate buffer of pH 3.6, 22 °C). An AUTOLAB with a VA-Stand 663 and a three-electrode system consisting of the HMDE as a working electrode with area 0.4 mm 2, an Ag/AgCl/3 mol l −1 KCl as a reference electrode and a Pt-wire as an auxiliary electrode was employed. The maize kernels exposed to the highest cadmium concentration (100 μmol l −1) germinated formerly and much better. A rapid increase of the fresh weight probably relates with more intensive uptake of water in order to decrease cadmium concentration. An intensive preservation of homeostasis of Cd 2+ ions in the germinating plants by defending mechanisms might explain differences of uptake rate of cadmium. The linear increase of GSH content with the exposure time at all studied concentration suggests the defending mechanisms might be triggered by concentrations of a heavy metal.

Prima Facie Evidence That a Phytocystatin for Transgenic Plant Resistance to Nematodes Is Not a Toxic Risk in the Human Diet

A protein-engineered rice cystatin (OcIDeltaD86) provides transgenic, partial crop resistance to plant nematodes. This study determined whether its oral uptake has adverse effects on male Sprague-Dawley rats when they are administered by oral gavage 0.1-10 mg OcIDeltaD86/kg body weight daily for 28 d. Body weight and water and food intakes were unaltered for most of the study. The only significant changes in fresh weight of nine organs were for the liver (4% decrease; P < 0.05) and the empty cecum (14% increase; P < 0.05) at the two lowest doses and the highest dose of OcIDeltaD86, respectively. No abnormalities in either organ were detected by histochemistry. There were no changes in the urine or in hematological variables measured, and blood serum revealed no dose-dependent responses for any of 17 variables measured. OcIDeltaD86 was degraded by boiling with a 50% loss of its inhibition of papain after 9.2 +/- 8.0 min. It also showed >95% loss of such inhibition after 15 s in simulated gastric fluid. The results suggest that the no effect level (NOEL) for OcIDeltaD86 is >10 mg/(kg. d). This provides a range of dietary exposure >200-2000 fold depending upon the promoter used to control its expression in potato.

The influence of weather factors on the drying rate of cut perennial ryegrass herbage under controlled conditions

The rates of drying of cut perennial ryegrass (Lolium perenne L.) herbage over short periods of time were measured in four experiments in a controlled environment room. Standard weights of 33·7 g grass dry matter (DM) were placed in half the area of wire‐mesh trays (0·5 m long × 0·3 m wide × 0·07 m high with 11‐mm‐square mesh) which, so as to simulate conditions in a swath, were supported on wooden frames within dark plastic boxes 25 mm above 35‐mm‐thick wet sponges. The trays of grass in the controlled environment room were weighed hourly for 7 h, drying rate being assessed by the change in grass fresh weight. Light was supplied from 400‐W mercury vapour lamps, while an air conditioning unit within the controlled environment room allowed control of vapour pressure deficit (VPD). Only one particular VPD could be created on any one day and resource limitations restricted the study to one replicate per day. The first experiment correlated drying rates under the mercury vapour lamps with drying rates in the open air under sunshine over 3 d. This work showed that a distance of 200 mm between the tray and lamps equated to 1081 W m–2, 400 mm to 432 W m–2 and 600 mm to 281 W m–2. Experiment 2, conducted with previously frozen grass, was a 4 × 4 factorial design with light intensity and VPD as factors. The third experiment (Experiment 3) compared the drying rate of freshly cut grass with grass that had previously been frozen in a 2 × 2 × 2 factorial design with the two grasses, two light intensities and two wind speeds as factors. The final experiment (Experiment 4) was a 3 × 2 × 2 factorial design with light intensity, VPD and wind speed as factors. A wind of approximately 3 m s–1 was simulated using a 22‐mm, 30 W fan set in a fixed position 600 mm from each tray plus grass. Fresh grass was cut each morning of the experiment. There were six replicates of each treatment. The effect of the three radiation intensities on grass DM concentration in Experiment 2 was highly significant (P &lt; 0·001). VPD had less effect (P &lt; 0·05). Results from Experiment 3 showed that previously frozen material dried much more rapidly than fresh grass and as a result would not simulate actual grass drying in the field. Consequently in Experiment 2 fresh grass was used as opposed to previously frozen material. In Experiment 4, light intensity had the greatest influence on grass drying followed by VPD and wind speed. However, the influence of wind speed was variable. A wind speed of ≈3 m s–1 increased the rate of water loss from grass with a low initial DM concentration (&lt;160 g kg–1) receiving low levels of solar radiation (281 W m–2), while at higher initial DM concentrations (&gt;210 g kg–1) and higher solar radiation levels (432 W m–2) the effect of wind was to slow grass drying. The results from Experiments 2 and 4 also indicated that high levels of either wind (3 m s–1) or VPD (&gt;6 mbars), when associated with low levels of solar radiation, resulted in large increases in grass DM concentration. However, these extreme weather conditions are unlikely to occur in practice.

Starch Accumulation Is Associated with Adventitious Root Formation in Hypocotyl Cuttings of Pinus radiata

This study of the internal physiology of adventitious root formation in Pinus radiata was performed without the potential complications from microbial contamination and nutritional stress. Hypocotyl cuttings of radiata pine were cultured in half strength MS nutrient medium supplemented with IBA (indole-3-butyric acid), IBA + kinetin, kinetin, or without phytohormones (control). Averages of 8.35 and 0.08 roots per cutting were formed in IBA and in growth regulator-free treatments, respectively. No roots were formed in IBA + kinetin, kinetin, or sucrose-free treatments at day 30 after excision of hypocotyls. Changes in fresh weight, sugar, and starch content were measured at established developmental stages associated with adventitious root formation. Sucrose-supplemented medium was required for higher levels of sugar, starch, and root formation in rooting region of IBA-treated hypocotyls. Starch accumulation, in particular, seems to have potential as a biochemical marker before root primordium emergence in light of the following observations in the IBA treatment. Starch began to build up preferentially in cells involved in or in close proximity to potential sites of new root primordium formation (that is, the cells on the inside of the cortex and the pith) before any visible organized root primordia and then began to disappear during root primordium formation. The substantial starch accumulation associated with IBA treatment was not observed in the IBA + kinetin, kinetin alone, growth regulator-free, sucrose-free treatments (nonrooting treatments) or in the nonrooting region of hypocotyls treated with IBA.

Accumulation of potassium and calcium by ripening berries on field vines of Vitis vinifera (L) cv. Shiraz

Ripening berries of Vitis vinifera (L) cv. Shiraz can show pre-harvest weight loss at sub-optimal sugar content (shrinkage). This later-age decline in berry weight implies that water loss from mature berries has begun to exceed water inflow from the parent grapevine. Such decrease in net inflow has been attributed to a cessation of xylem flow subsequent to veraison, followed by a cessation of phloem flow into berries during later stages of ripening. We address this issue in this present paper, and show a continuing increase in berry content of both potassium and calcium throughout ripening. We measured changes in berry fresh weight and berry content of potassium (phloem mobile) and calcium (phloem immobile) in fruit on field vines sampled from set to harvest. Berry fresh weight reached a plateau between 81 and 95 days after flowering, then declined to 75% of maximum fresh weight by 115 days. Dry weight maximum occurred 14 days after the onset of the fresh weight plateau. Potassium accumulation was slow pre-veraison, increased 3.5-fold post-veraison, and continued during berry shrinkage. Calcium content per berry also showed a linear increase throughout fruit enlargement and ripening phases. Assuming both potassium and calcium were entering berries via vascular conduits, our results imply a continuing connection between parent grapevine and ripening berries. Moreover, an abrupt change (increase) in the ratio of potassium/calcium content per berry subsequent to veraison implies that phloem inflow has increased relative to xylem inflow during post-veraison enlargement.

Changes in the essential oil content and its composition during palmarosa (Cymbopogon martinii (Roxb.) Wats. var.motia) inflorescence development

The flowering tops of palmarosa (Cymbopogon martinii) consist of spikelets and each spikelet is further composed of racemes and a leaf-like structure called a spathe. Both racemes and spathe contain essential oil. Changes in fresh weight, dry weight, chlorophyll and essential oil content and its major constituents, viz. geraniol and geranyl acetate, were examined for both racemes and spathe at various stages of spikelet development. The essential oil content was maximal at the unopened spikelets stage and decreased significantly thereafter. At unopened spikelets stage, the proportion of geranyl acetate (58.6%) in the raceme oil was relatively greater compared with geraniol (37.2%), whereas the spathe oil contained more geraniol (61.9%) compared with geranyl acetate (33.4%). The relative percentage of geranyl acetate in both the oils, however, decreased significantly with development and this is accompanied by a corresponding increase in the percentage of geraniol. Analysis of the volatile constituents from racemes and spathes (from mature spikelets) and seeds by capillary GC indicated 28 minor constituents besides the major constituent geraniol. (E)-Nerolidol was detected for the first time in an essential oil from this species. The geraniol content predominated in the seed oil, whereas the geranyl acetate content was higher in the raceme oil. Copyright © 2000 John Wiley & Sons, Ltd.

Storage reserve mobilization during low temperature germination and early seedling growth in Brassica napus

In western Canada, oilseed rape ( Brassica napus L. var. oleifera cv. Westar) is seeded during the early months of spring, when ambient temperatures are well below the optimum. This can result in poor seedling emergence. The objectives of the present study were to determine which developmental stages are sensitive to low temperature and whether the effects are thermal or developmental in nature. Seed was germinated at 22, 10 and 6 °C. Fresh weight changes and seedling growth were assessed on the basis of equal accumulated heat units, and the mobilization of storage reserves was assessed by employing antibodies against isocitrate lyase (ICL; EC 4.1.3.1), oleosin and cruciferin. Additionally, de novo protein synthesis was determined by quantifying the incorporation of methionine via in vivo labelling. Low temperature resulted in poor germination and early seedling growth with phase II of germination being most sensitive. At 10 °C, there was a temporal delay in germination that did not affect the overall success of germination. This was a thermal effect as seed at the lower temperatures required the equivalent of 16–24 degree days before germination occurred. Also, seedling growth at 10 °C was lower in comparison to seedlings grown at 22 °C. Seed at 6 °C displayed slow and incomplete germination and poor seedling growth as a result of both thermal and developmental effects.

Reconsideration of the use of deionized water as vase water in postharvest experiments on cut flowers

The relevance of deionized water as a control treatment in vase life experiments and the effects of major tap water components on cut flower water balance were investigated. Chrysanthemum (Dendranthema x grandiflorum Tzvelev cv. Cassa) was used in all experiments. Deionized water gave a sharp decrease in fresh weight of the cut flowers after 1–3 days. This decrease was absent in tap water. After 4 days in deionized water, hydraulic resistance in the basal part of the stem was ∼50 times the value of fresh cut flowers and seven times the value in tap water. Change in fresh weight during vase life in a solution containing combinations of CaCl2, NaHCO3 and Cu2+ at concentrations commonly present in tap water was similar to that in tap water. However, none of the minerals tested by themselves gave fresh weight results similar to those from using tap water. In the combined solution, hydraulic resistance in the basal part of the stem after 4 days was comparable to that in tap water. A minimal amount of Cu2+ (>0.30 mg·l−1) enhanced fresh weight, probably by reducing bacterial growth in the cut open vessels. Calcium chloride (>0.7 mM) delayed the increase in hydraulic resistance in the stem (not including the basal 3 cm) compared to deionized water, and at a high concentration (10.7 mM), substantially decreased the transpiration rate. Sodium bicarbonate (1.5 mM) neither affected hydraulic resistance nor transpiration rate, but positively influenced fresh weight change during vase life when combined with CuSO4 and as compared to deionized water. Results strongly question the appropriateness of deionized water as a control solution in vase life experiments.

Reconsideration of the use of deionized water as vase water in postharvest experiments on cut flowers

Abstract The relevance of deionized water as a control treatment in vase life experiments and the effects of major tap water components on cut flower water balance were investigated. Chrysanthemum ( Dendranthema x grandiflorum Tzvelev cv. Cassa) was used in all experiments. Deionized water gave a sharp decrease in fresh weight of the cut flowers after 1–3 days. This decrease was absent in tap water. After 4 days in deionized water, hydraulic resistance in the basal part of the stem was ∼50 times the value of fresh cut flowers and seven times the value in tap water. Change in fresh weight during vase life in a solution containing combinations of CaCl 2 , NaHCO 3 and Cu 2+ at concentrations commonly present in tap water was similar to that in tap water. However, none of the minerals tested by themselves gave fresh weight results similar to those from using tap water. In the combined solution, hydraulic resistance in the basal part of the stem after 4 days was comparable to that in tap water. A minimal amount of Cu 2+ (>0.30 mg·l −1 ) enhanced fresh weight, probably by reducing bacterial growth in the cut open vessels. Calcium chloride (>0.7 mM) delayed the increase in hydraulic resistance in the stem (not including the basal 3 cm) compared to deionized water, and at a high concentration (10.7 mM), substantially decreased the transpiration rate. Sodium bicarbonate (1.5 mM) neither affected hydraulic resistance nor transpiration rate, but positively influenced fresh weight change during vase life when combined with CuSO 4 and as compared to deionized water. Results strongly question the appropriateness of deionized water as a control solution in vase life experiments.

Reduced Lipid Pecans: Chemical Alterations and Implications for Quality Maintenance during Storage

The unextracted and reduced lipid (supercritical carbon dioxide extraction of 22% and 27% (w/w) of total lipids) pecan [Carya illinoinensis (Wangenh.) K. Koch] kernels packaged in 21% O2, 79% N2 were analyzed for color, hexanal, sensory, fresh weight, and lipid class changes periodically during 37 weeks of storage at 25 °C and 55% relative humidity. Pecan nutmeats were lightened by partial lipid extraction. The pecan testa darkened (decreasing chromameter L*) with storage time. Most color changes occurred in the first 18 weeks. Hexanal concentration of reduced-lipid pecans was negligible throughout storage, while unextracted pecans reached excessive levels by week 22 of storage. Hexanal concentration, indicative of rancidity, was in agreement with sensory analysis results with the hexanal threshold level for objectionable rancidity ranging from 7 to 11 mg·kg-1 pecans. Weight change was negligible during storage, except in 27% reduced-lipid pecans. Free fatty acids increased with storage and were significantly higher in unextracted pecans than the reduced-lipid pecans at 0, 10, 18, 32, and 37 weeks of storage. Shelf life of pecans with partial lipid extraction was longer than unextracted pecans. In addition to decreasing the total amount of lipid available for oxidation, the free fatty acid lipid component that correlated with the development of rancidity was reduced by extraction.

662 Genetics and Physiology of Postharvest Cut Flower Longevity

Efforts to improve postharvest longevity of fresh-cut flowers has only recently turned toward selection and breeding. Conventional methods to extend keeping longevity of cut flowers depend on use of chemical treatment placed in holding solutions. Postharvest longevity studies were initiated with Antirrhinum majus L. (snapdragon) to determine: if natural genetic variation existed for cut-flower longevity, the inheritance of the trait, heritability, and associated physiology. Evaluation of commercial inbreds held in deionized water revealed a range in cut-flower longevity from a couple of days to 2.5 weeks. The shortest- and longestlived inbreds were used as parents in crosses to study the aforementioned areas of interest. Information will be presented on inheritance of cut flower longevity based on populations evaluated from matings for generation means analysis and inbred backcross method. Also presented will be information on stomata, transpiration, carbohydrate, fresh-weight change, and forcing temperature relative to postharvest longevity.

Effect of 2,4-D on the Nitrate Assimilation Process in Cowpea Shoot

Cowpea seedlings were grown in earthen pots in normal sunlight and irrigated daily with 10 mM nitrate solution. These seedlings were supplied with a known concentration of 2,4-D, an auxinic herbicide, and harvested after 1, 3, and 7 days. The whole shoot tissue was used for various estimations. A decrease (12 to 28%) in total phosphorus, starch, dry weight, and nitrite reductase in treated plants was observed. However, a tremendous increase was observed in nitrate reductase activity (80%) in treated plants, both onin vivoandin vitroassays. 2,4-D-treated plants also had significantly higher endopeptidase activity. An increase in aminotransferases occurred on the 1st and 3rd days of treatment, and thereafter on the 7th day the activities were nearly the same as that in the parallel control. An increase in protein content of 18% on fresh weight and 46% on dry weight basis occurred. On the other hand changes in fresh weight were insignificant. NO3-content also remained nearly the same on the 1st and 3rd days but on the 7th day an increase of 19% in 2,4-D-treated plants was evident. The nitrate assimilation process in cowpea in light of these observations is discussed, and it is proposed that 2,4-D selectively affected the pathway of nitrate reduction.

Micropropagation, decontamination, transcontinental shipping and hydroponic growth of Cattleya while sealed in semipermeable membrane vessels

Two varieties of Cattleya orchids ( Cattleya loddigessi `Elen'× C. loddigessi Alba `Extra' and Brassolaeliocattleya. Mem. `Helen Brown' Sweet Afton) were micropropagated in sealed, 3-dimensional polypropylene vessels with microporous, semipermeable membrane films. Plantlets in these vessels were grown in vitro and shipped, including post-storage recovery in a hydroponic system. During tissue culture on sugar-containing media, chance contaminants were eliminated on the vessels' outer surface. Decontamination did not affect biomass, carbohydrate content or subsequent growth of tissues contained within the vessels. Plantlets were shipped from Japan to the United States and arrived without changes in fresh or dry weight of whole plantlets, however, shoot dry weight increased significantly. Sucrose, glucose and fructose reserves established on sugar containing media were utilized during shipping while shoot dry weight increased. Plantlets grew photoautotrophically in hydroponic culture in the greenhouse in the same sealed-membrane vessels. Carbohydrate concentration of plantlets following hydroponic culture was not significantly different than levels after the shipping process. Sealed-membrane vessels for micropropagation, decontamination, shipping and greenhouse growth were useful for culture of Cattleya and facilitate scale-up of materials handling and international commerce of tissue-cultured plants.

Developmental regulation of polysaccharide metabolism and growth in the primary cell walls of maize

During development of the intact maize ( Zea mays L.) coleoptile a correspondence exists between the rate of change in length and fresh weight but these parameters, that reflect growth, are all preceded by the accumulation of dry weight by the tissue. Coleoptile dry weight increases rapidly for the first 3–4 days commensurate with tissue formation with evidence for specific biosynthesis including the net incorporation into the cell wall of protein and substantial deposition of β-(1,3)(1,4) glucan. After day 4 the extractable wall protein and after day 5 the β-(1,3)(1,4) glucan begin to decline while the deposition of glucuronoarabinoxylan continues. Despite the continued incorporation of specific polymers into the wall the accumulated mass does not augment the overall dry weight. The shifts in polysaccharide distribution with development are consistent with what would be expected in terms of changes in the autolytic degradation of the wall. Glucan autolysis in isolated cell walls is relatively inactive initially then increases to a maximum by day 4 while arabinoxylan autolysis undergoes only relatively minor changes. Changes in the extent of wall glucan autolysis is proportional to the levels of glucanase activities extracted from the cell wall during the developmental sequence. Glucan in walls of the first three leaves of the maize seedlings also reflects dynamic turnover in correspondence with growth much like that of the coleoptile, suggesting that glucan metabolism coincides with growth in other maize tissues. The acceleration of glucan turnover mediated by auxin in situ may result from combinations and/or interactions of proteins that promote synergistic polysaccharide hydrolysis.

Chemical and Physiological Changes During the Embryonic Development of the Spider Crab, Hyas araneus L. (Decapoda: Majidae)

During embryogenesis of the spider crab, Hyas araneus, four developmental phases were distinguished microscopically: cleavage, gastrula, embryo differentiation, prehatching phase. Changes in fresh weight (FW), dry weight (DW), ash-free dry weight (AFDW), water, carbon (C), nitrogen (N), total lipids, proteins, carbohydrates, and respiration rates were measured in developing eggs. The percentage of water increased from 52% to 87% of FW, most rapidly after the beginning of organ differentiation and during hatching. The accumulation of minerals followed a similar pattern, with ash increasing from 3% to 7% of DW in the eggs, and to 26% at hatching. Inverse (decreasing) patterns were observed in organic matter (AFDW, C, N, lipids, proteins). During development from the undivided egg to the freshly hatched zoea larva, 69% of the initial lipid and 35% of protein were depleted. Carbohydrates represented a minor constituent of yolk (1% to 2% of DW). In spite of a decreasing protein content, N remained almost constant. This suggests a final increase in low-molecular nitrogenous substances, which are not quantitatively detected by the Lowry method (probably free amino acids); we suspect that these may play a role in the hatching process. In the gastrula, and from about 3 months after the onset of organ differentiation until 1 or 2 months before hatching, low embryonic respiration rates as well as microscopical observations indicated the existence of developmental resting periods. Such diapause-like intervals may coordinate the time of hatching with a short season of planktonic food production in high latitudes. The relative importance of lipids and proteins as fuel for embryogenesis is compared with that in other crustacean taxa.

Micropropagation, Decontamination, Transcontinental Shipping and Hydroponic Growth of Cattleya while Sealed in Semipermeable Membrane Vessels

Two varieties of Cattleya orchids (C. Loddigessi `Elen' × C. Loddigessi Alba `Extra' and Brassolaeliocattleya. Mem. `Helen Brown' Sweet Afton) were micropropagated in sealed, three-dimensional polypropylene vessels with microporous, semi-permeable membrane films to allow diffusion of water, dissolved nutrients, and gas to plant material inside the vessels. During tissue culture on sugar-containing media, chance contaminants were eliminated on the vessels outer surface using 5% bleach solution. Proper decontamination treatment did not effect carbohydrate content or subsequent growth of tissues contained within the vessels. Plantlets remaining in membrane vessels were shipped (7 days at 14–30°C) from Japan to the United States in the dark in a plastic tray and arrived without changes in fresh or dry weight of whole plantlets. However, shoot dry weight did increase significantly. Sucrose, glucose, and fructose reserves established on sugar-containing media were greater in root than shoot tissue and were largely expended during shipping concurrent with increased shoot dry weight. It is likely carbohydrate catabolism provided energy for these CAM plantlets to continue carbon fixation, resulting in positive net carbon assimilation in the dark shipping environment. Changes in starch concentrations during shipping were not significant. Plantlets grew photoautotrophically in hydroponic culture in the greenhouse, following transport in the same sealed membrane vessels. Carbohydrate concentration of plantlets following hydroponic culture was not significantly different than after the shipping process. Sealed-membrane vessels for micropropagation, decontamination, shipping and greenhouse growth were useful for culture of Cattleya to facilitate scale-up of materials handling and international commerce of tissue-cultured plants.

Uterine growth, cell proliferation, and c-fos proto-oncogene expression throughout the estrous cycle in ewes.

Uterine growth, cell proliferation, and endometrial expression of the c-fos proto-oncogene were evaluated for nonpregnant ewes (n = 6 ewes per day) on Days 0 (estrus), 2, 4, 8, 12, and 15 of the estrous cycle. Fresh and dry weights of uterine horns decreased (p < 0.01) linearly from Days 0 to 8 and then remained similar from Day 8 through Day 15. Tissue water content (1 - [dry weight/fresh weight]) was greater on Day 0 (p < 0.01) than on Days 2, 4, and 8, and the latter values were greater (p < 0.01) than on Days 12 and 15. DNA content was similar on Days 0, 2, 4, 8, and 15 but increased (p < 0.01) on Day 12. Although DNA content was greatest on Day 12, the ratios of RNA to DNA and of protein to DNA were least (p < 0.01) on that day. Thus, changes in uterine fresh weight were associated primarily with changes in tissue hypertrophy (RNA:DNA and protein:DNA ratios) and water content. In addition, changes in uterine fresh weight were associated with changes in the ratio of estradiol to progesterone in systemic blood, which was greatest (p < 0.01) on Days 0 and 2, decreased (p < 0.01) from Day 2 to Day 8, remained low through Day 12, and then was elevated again (p < 0.01) on Day 15. Moreover, compartmentalized changes in endometrial cell proliferation (labeling index [LI]; percentage of cells exhibiting nuclear incorporation of bromodeoxyuridine, a thymidine analogue) also were associated with the changes in fresh weight. The epithelium of the uterine lumen and luminal glands exhibited the greatest changes in rate of cell proliferation and accounted for most of the changes in LI seen across days of the estrous cycle. Endometrial expression of c-fos mRNA and protein also reflected changes in uterine weight and the systemic estradiol:progesterone ratio. The level of c-fos mRNA was greatest at estrus, low on Days 2-8, and elevated slightly on Days 12 and 15; Fos protein was greatest on Days 0 through 4, least on Day 8, and intermediate on Days 12 and 15. Characterization of uterine growth, cell proliferation, and c-fos expression throughout the estrous cycle will provide a foundation for future studies of gene expression regulating growth of the nonpregnant uterus.