Dynamics of non-structural carbohydrates in developing leaves, bracts and floral buds of cotton

Development of cotton (Gossypium hirsutum L.) squares (i.e. floral buds with bracts) is fundamental for yield formation. A 2-year field study was conducted to determine dry weight (DW) accumulations of cotton leaves, floral bracts and floral buds, and the changes in concentrations of non-structural carbohydrates (hexoses, sucrose and starch) in these tissues during square ontogeny as affected by fruiting positions within the plant canopy. During square development, DW accumulation of a subtending sympodial leaf and floral bracts followed a sigmoid growth curve with increasing square age, whereas the DW increase of a floral bud followed an exponential curve. Main-stem node (Node 8, 10 or 12) and branch position (proximal vs. distal) within a plant canopy significantly affected DW accumulations of the leaf, bracts and floral bud. Starch was the dominant non-structural carbohydrate in the three tissues, accounting for more than 65% of total non-structural carbohydrates (TNC). Subtending leaf TNC increased as square age increased. The bracts exhibited a smaller change in TNC than leaves. Non-structural carbohydrate concentration was the lowest in 10-day-old floral buds, and had little change during the first 15 days of square development. Within 5 days prior to anthesis, the floral-bud TNC increased dramatically, tripling at the time of floral anthesis compared with 15-day-old floral buds. Square age and fruiting position significantly affected non-structural carbohydrate concentrations of subtending leaves, bracts, and floral buds. The correlation did not exist between final boll retention and non-structural carbohydrate concentrations of floral buds at different fruiting positions under normal growth conditions. The pattern of floral-bud non-structural carbohydrates during square ontogeny suggests that major events in carbohydrate metabolism occur just prior to anthesis.     

Parent-ramet connections in Agave deserti: influences of carbohydrates on growth

Summary Agave deserti, a monocarpic perennial occurring in the northwestern Sonoran Desert, produces ramets on rhizomes that extend from the base of a parent plant. Shading ramtes to light compensation for two years did not decrease their relative growth rate (RGR) compared with unshaded ramets. However, the parents experienced a 30% decrease in total nonstructural carbohydrate (TNC) level, suggesting that carbohydrates were translocated from parents to ramets. Shaded parents had RGR's similar to unshaded parents, due in large part to consumption of 50% of the TNC reserves of shaded parents, but about 10% of the growth of the shaded parents was attributed to TNC received from their attached ramets. Estimates of parent and ramet growth separately, based on changes in TNC levels (converted to dry weight using a measured production value), net CO₂ uptake of unfolded leaves, and respiration of roots, stems, and folded leaves, were similar to measured growth of parents and ramets combined, suggesting that parents and ramets are physiologically integrated and grow as a unit. Large TNC reserves, which were also shown to support growth during conditions of water limitation in the field, enhance the growth of ramets in an environment where seedling establishment is rare.Abbreviations DW dry weight - EPI environmental productivity index - PAR photosynthetically active radiation - RGR relative growth rate - TNC total nonstructural carbohydrate     

Rhizome dynamics and resource storage in Phragmites australis

Seasonal changes in rhizome concentrations of total nonstructural carbohydrates (TNC), water soluble carbohydrates (WSC), and mineral nutrients (N, P and K) were monitored in two Phragmites australis stands in southern Sweden. Rhizome biomass, rhizome length per unit ground area, and specific weight (weight/ length ratio) of the rhizomes were monitored in one of the stands.Rhizome biomass decreased during spring, increased during summer and decreased during winter. However, changes in spring and summer were small (< 500 g DW m-2) compared to the mean rhizome biomass (approximately 3000 g DW m^–2). Winter losses were larger, approximately 1000 g DW m-2, and to a substantial extent involved structural biomass, indicating rhizome mortality. Seasonal changes in rhizome length per unit ground area revealed a rhizome mortality of about 30% during the winter period, and also indicated that an intensive period of formation of new rhizomes occurred in June.Rhizome concentrations of TNC and WSC decreased during the spring, when carbohydrates were translocated to support shoot growth. However, rhizome standing stock of TNC remained large (> 1000 g m^–2). Concentrations and standing stocks of mineral nutrients decreased during spring/ early summer and increased during summer/ fall. Only N, however, showed a pattern consistent with a spring depletion caused by translocation to shoots. This pattern indicates sufficient root uptake of P and K to support spring growth, and supports other evidence that N is generally the limiting mineral nutrient for Phragmites.The biomass data, as well as increased rhizome specific weight and TNC concentrations, clearly suggests that reloading of rhizomes with energy reserves starts in June, not towards the end of the growing season as has been suggested previously. This resource allocation strategy of Phragmites has consequences for vegetation management.Our data indicate that carbohydrate reserves are much larger than needed to support spring growth. We propose that large stores are needed to ensure establishment of spring shoots when deep water or stochastic environmental events, such as high rhizome mortality in winter or loss of spring shoots due to late season frost, increase the demand for reserves.     

Effects of temperature on embryonic and early larval growth and development in the rough-skinned newt (Taricha granulosa)

We investigated the effects of temperature on the growth and development of embryonic and early larval stages of a western North American amphibian, the rough-skinned newt (Taricha granulosa). We assigned newt eggs to different temperatures (7, 14, or 21 °C); after hatching, we re-assigned the newt larvae into the three different temperatures. Over the course of three to four weeks, we measured total length and developmental stage of the larvae. Our results indicated a strong positive relationship over time between temperature and both length and developmental stage. Importantly, individuals assigned to cooler embryonic temperatures did not achieve the larval sizes of individuals from the warmer embryonic treatments, regardless of larval temperature. Our investigation of growth and development at different temperatures demonstrates carry-over effects and provides a more comprehensive understanding of how organisms respond to temperature changes during early development.     

Estimating recent growth in the cuttlefish Sepia officinalis: are nucleic acid-based indicators for growth and condition the method of choice?

A laboratory calibration study was undertaken with juvenile Sepia officinalis (80-85 g initial wet weight) to investigate the effects of different food rations and different starving intervals on RNA/dry weight (DW) ratios and RNA/DNA ratios in cephalopod mantle muscle at two different temperatures. The digestive gland index was also used as an additional indicator of recent growth. High food rations and low temperature went along with high RNA/DW ratios and high RNA/DNA ratios. Starving resulted in a linear decline in growth performance and a concomitant decrease in RNA/DW and RNA/DNA ratio, with RNA/DNA ratios representing the growth data better. RNA/DNA ratios decreased faster at higher temperatures. A fluorimetric assay for nucleic acid analysis was optimized for cephalopod mantle tissues and yielded reproducible RNA/DNA ratios with a relative variance below 10%. Thus, it may be possible to use this estimator of recently encountered feeding regime for the evaluation of mortality rates of early teuthid paralarvae to eventually support stock management. Also, log relative digestive gland weight showed a strong relationship with starving time, but, surprisingly, not with temperature. Data from the two temperatures analyzed could be combined to form a common regression line of relative digestive gland index with starving time. This indicator for recent growth might be especially suitable for large specimens with a well-developed digestive gland.     

Effects of temperature on cell growth and xanthan production in batch cultures of Xanthomonas campestris

Batch xanthan fermentations by Xanthomonas campestris NRRL B-1459 at various temperatures ranging between 22 degrees C and 35 degrees C were studied. At 24 degrees C or lower, xanthan formation lagged significantly behind cell growth, resembling typical secondary metabolism. However, at 27 degrees C and higher, xanthan biosynthesis followed cell growth from the beginning of the exponential phase and continued into the stationary phase. Cell growth at 35 degrees C was very slow; the specific growth rate was near zero. The specific growth rate had a maximum value of 0.26 h(-1) at temperatures between 27 degrees C and 31 degrees C. Cell yield decreased from 0.53 g/g glucose at 22 degrees C to 0.28 g/g glucose at 33 degrees C, whereas xanthan yield increased from 54% at 22 degrees C to 90% at 33 degrees C. The specific xanthan formation rate also increased with increasing temperature. The pyruvate content of xanthan produced at various temperatures ranged between 1.9% and 4.5%, with the maximum occurring between 27 degrees C and 30 degrees C. These results suggest that the optimal temperatures for cell growth are between 24 degrees C and 27 degrees C, whereas those for xanthan formation are between 30 degrees C and 33 degrees C. For single-stage batch fermentation, the optimal temperature for xanthan fermentation is thus dependent on the design criteria (i. e., fermentation rate, xanthan yield, and gum qualities). However, a two-stage fermentation process with temperature shift-up from 27 degrees C to 32 degrees C is suggested to optimize both cell growth and xanthan formation, respectively, at each stage, and thus to improve overall xanthan fermentation.     

Resource allocation and storage relative to resprouting ability in wind disturbed coastal forest trees

Many plants persist by resprouting after disturbance. However, the benefits of resprouting (survival) may be traded off against height growth and reproduction. Resources (total non-structural carbohydrates—TNC) that could be allocated to growth or reproduction are stored or mobilised to support resprouting. TNC may either be stored by accumulation where availability exceeds the requirements for growth, or by reserve formation when storage is at the expense of growth. Thus, the mechanism of storage and resource allocation may differ between good (R+) and poor (R?) resprouters in response to nutrient availability and disturbance regime. R+ species typically reserve resources to ensure a rapid resprouting response to disturbance. We test whether R+ and R? species in coastal forest, under chronic wind disturbance, differ in growth rates, biomass allocation, leaf traits, water relations and storage of TNC. Seedlings from three confamilial pairs of R+ and R? tree species were subjected to nitrogen addition, water stress and clipping (simulating herbivory) treatments under greenhouse conditions. R? species had greater height growth rates, larger specific leaf area, lower root mass ratio and lower root TNC than R+ species. These differences between R+ and R? species were maintained irrespective of the levels of nitrogen, water and clipping treatments. R+ species did not increase their TNC concentration under nutrient and water stress, indicating that TNC is stored by reserve formation. R+ species appeared to trade-off growth against storage, while R? species did not. In R+ species, reserve formation is likely a bet-hedging strategy against occasional strong selection events in addition to chronic wind stress. By trading off height growth for better resprouting ability, good resprouters may be able to persist at more frequently disturbed sites (e.g., dune crests and windward slopes), while poor resprouters that have faster height growth can dominate less disturbed sites.     

Light induces petal color change in Quisqualis indica (Combretaceae)

Petal color change, a common phenomenon in angiosperms, is induced by various environmental and endogenous factors. Interestingly, this phenomenon is important for attracting pollinators and further reproductive success. Quisqualis indica L. (Combretaceae) is a tropical Asian climber that undergoes sequential petal color change from white to pink to red. This color changing process is thought to be a good strategy to attract more pollinators. However, the underlying physiological and biochemical mechanisms driving this petal color change phenomenon is still underexplored. In this context, we investigated whether changes in pH, pollination, light, temperature or ethylene mediate petal color change. We found that the detected changes in petal pH were not significant enough to induce color alterations. Additionally, pollination and temperatures of 20-30℃ did not alter the rate of petal color change; however, flowers did not open when exposed to constant temperatures at 15℃ or 35℃. Moreover, the application of ethylene inhibitor, i.e., silver thiosulphate, did not prevent color change. It is worth mentioning here that in our study we found light as a strong factor influencing the whole process of petal color change, as petals remained white under dark conditions. Altogether, the present study suggests that petal color change in Q. indica is induced by light and not by changes in petal pH, pollination, ethylene, or temperature, while extremely low or high temperatures affect flower anthesis. In summary, our findings represent the probable mechanism underlying the phenomenon of petal color change, which is important for understanding flower color evolution.     

Transient studies of nutrient uptake, growth, and indole alkaloid accumulation in heterotrophic cultures of hairy roots of Catharanthus roseus

The kinetics of growth, the uptake of macronutrients, and the accumulation of indole alkaloids were investigated in long-term, heterotrophically cultured transgenic ("hairy") roots of Catharanthus roseus.Tabersonine, ajmalicine, and serpentine were monitored over a 70-day period. The doubling time [dry-weight (DW) basis] of C. roseus hairy roots in B5/2 nutrients supplemented with 3% sucrose was 3.6 days. NH(4) (+), NO(3),(-) and P(i) were depleted sequentially from culture medium by hairy roots, while sugars remained undepleted. The growth-limiting nutrient was inorganic nitrogen, NH(4) (+) and NO(3) (-), with exponential-phase overall biomass yields of 34.1 and 5.0 g DW/g nutrient, respectively. Extracellular pH decreased to 4.8 in early exponential phase of culture growth from the initially adjusted value of 5.7, increased subsequently to a maximum of 7.7 in late exponential phase of growth coincident with the maximum of fresh weight (FW)/DW ratio, before decreasing to 5.5-5.0. The organic acids, pyruvate, formate, lactate, and succinate were excreted by hairy roots starting in late phase of exponential growth, possibly resulting in the late-culture pH decrease. Tabersonine accumulation was distinctly growth associated with maximum specific and total yields of 1.15 mg/g DW and 5.6 mg/L, respectively, in late-exponential phase of growth. Serpentine accumulation was non growth associated with increasing specific and total levels in stationary growth phase: 1.3 mg/g DW and 10.5 mg/L, respectively. The accumulation of ajmalicine also appeared growth associated. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 527-534, 1997.     

Effects of temperature on growth rate and behavior of Epeorus albertae (Ephemeroptera: Heptageniidae) nymphs

Anthropogenic disturbances affect temperature in river systems. Temperature potentially affects life histories of macroinvertebrates and alters behavior and biological functions. Temperature preferences and tolerance ranges for key taxa are therefore critical for understanding impacts of human-induced changes to water temperatures on river ecosystems. The objective of this study was to examine the effect of water temperature on growth rate and behavior of Epeorus albertae (McDunnough) nymphs. Nymphs were collected from the Umatilla River in eastern Oregon, and exposed to temperatures of 18, 22, and 28 °C. Nymphs held at 28 °C exhibited increased growth rates compared with individuals held at 18 and 22 °C. However, at 28 °C the accumulation of nymphal tissues was not consistent with that of nymphs held in lower temperatures; ratios of head capsule width to total body length were significantly lower in individuals at 28 °C compared with those held at the lower temperatures. This indicates that the nymphs held at the high temperature had longer total body length relative to the developmental stage, represented by head capsule width, when compared with insects in cooler temperatures. To examine the effect of water temperature on behavior, active drift of mayflies was examined in experimental chambers held at 12, 18, 22, and 28 °C. The number of drifting insects observed was significantly higher at 28 °C compared with 22, 18, and 12 °C. These results indicate that temperature is a factor influencing growth and behavior of E. albertae and is likely to lead to limitations in habitat use of this mayfly.     

Mannitol metabolism in cultured plant cells

Non-structural storage carbohydrates were measured in 9-day-old barley ( Hordeum vulgare L. cv. Brant) primary leaves. Accumulation rates of starch, sucrose and total non-structural carbohydrates (TNC) were approximately linear when measured between 2- and 12-h of light. Progressively higher TNC accumulation rates were observed at higher irradiance levels (i.e., comparing 250, 550 and 1050 ·mol m⁻² s⁻¹). Synthesis of a low-molecular-weight fructan also was enhanced by high irradiances. Low irradiance treatments decreased leaf sucrose levels and there was a corresponding increase in the lag period preceding starch synthesis in the light. Increased starch accumulation rates were usually observed when sucrose concentrations were high. These and other results suggested that cytosolic sucrose concentrations affected starch metabolism in the chloroplast. However, sucrose accumulation rates increased and starch storage decreased when barley seedlings were transferred from 20 to 10°C during the light period. Lowering the night temperature from 20 to 10°C for a single dark period 8-days after planting increased the TNC content of barley primary leaves at the beginning of day nine. In this experiment, TNC accumulation rates of treated and untreated leaves were similar. Changes in the accumulation rate of TNC were usually observed within 2- to 4-h after barley seedlings were exposed to altered environmental conditions. Monitoring rapid changes in leaf carbohydrate levels is a sensitive method for assessing the effects of environmental treatments on photosynthetic metabolism.     

Distinct responses of growth and respiration to growth temperatures in two mangrove species

Background and AimsMangrove plants are mostly found in tropical and sub-tropical tidal flats, and their limited distribution may be related to their responses to growth temperatures. However, the mechanisms underlying these responses have not been clarified. Here, we measured the dependencies of the growth parameters and respiration rates of leaves and roots on growth temperatures in typical mangrove species.MethodsWe grew two typical species of Indo-Pacific mangroves, Bruguiera gymnorrhiza and Rhizophora stylosa, at four different temperatures (15, 20, 25 and 30 °C) by irrigating with fresh water containing nutrients, and we measured growth parameters, chemical composition, and leaf and root O₂ respiration rates. We then estimated the construction costs of leaves and roots and the respiration rates required for maintenance and growth.Key ResultsThe relative growth rates of both species increased with growth temperature due to changes in physiological parameters such as net assimilation rate and respiration rate rather than to changes in structural parameters such as leaf area ratio. Both species required a threshold temperature for growth (12.2 °C in B. gymnorrhiza and 18.1 °C in R. stylosa). At the low growth temperature, root nitrogen uptake rate was lower in R. stylosa than in B. gymnorrhiza, leading to a slower growth rate in R. stylosa. This indicates that R. stylosa is more sensitive than B. gymnorrhiza to low temperature.ConclusionsOur results suggest that the mangrove species require a certain warm temperature to ensure respiration rates sufficient for maintenance and growth, particularly in roots. The underground temperature probably limits their growth under the low-temperature condition. The lower sensitivity of B. gymnorrhiza to low temperature shows its potential to adapt to a wider habitat temperature range than R. stylosa. These growth and respiratory features may explain the distribution patterns of the two mangrove species.     

Local weather conditions have complex effects on the growth of blue tit nestlings

Adverse weather conditions are expected to result in impaired nestling development in birds, but empirical studies have provided equivocal support for such a relationship. This may be because the negative effects of adverse weather conditions are masked by parental effects. Globally, ambient temperatures, rainfall levels and wind speeds are all expected to increase in a changing climate and so there is a need for a better understanding of the relationship between weather conditions and nestling growth. Here, we describe a correlative study that examined the relationships between local temperatures, rainfall levels and wind speeds and the growth of individual blue tit (Cyanistes caeruleus) nestlings in relation to their hatching order and sex. We found that changes in a range of morphological characters were negatively related to both temperature and wind speed, but positively related to rainfall. These patterns were further influenced by the hatching order of the nestlings but not by nestling sex. This suggests that the predicted changes in local weather conditions may have complex effects on nestling growth, but that parents may be able to mitigate the adverse effects via adaptive parental effects. We therefore conclude that local weather conditions have complex effects on avian growth and the implications for patterns of avian growth in a changing climate are discussed.     

Seasonal variation in dry weight and elemental composition of the early developmental stages of Petrolisthes laevigatus (Guérin, 1835) (Decapoda: Porcellanidae) in the Seno de Reloncaví, southern Chile

In the Seno de Reloncaví, southern Chile, seasonal changes in dry weight (DW) and elemental composition (CHN) were studied in embryo (initial embryonic stage), newly hatched zoeae, and newly settled megalopae of a porcelain crab, Petrolisthes laevigatus. Samples were taken throughout the seasons of egg laying (March-December), hatching (August-February), and settlement (October–February). Values of DW and CHN per embryo or larva, respectively, were consistently minimum in the middle of each season and maximum near its beginning and end. Patterns of seasonal variation in early embryonic biomass may thus be carried over to larvae at hatching and, possibly, to the settlement stage. Such carry-over effects may be selectively advantageous, as zoeae released at the beginning or near the end of the hatching season face conditions of poor planktonic food availability in combination with low winter temperatures or decreasing temperatures at the end of summer (enforcing long development duration). Hence, an enhanced female energy allocation into egg production may subsequently translate to enhanced yolk reserves remaining at hatching, allowing for a larval development under unfavourable winter conditions. In summer, by contrast, plankton productivity and temperatures are generally high, allowing for fast larval growth and development. This coincides with minimal biomass and energy contents both at hatching and settlement. In conclusion, our data suggest that seasonal patterns in the biomass of early developmental stages of P. laevigatus may reflect phenotypic variability as an adaptive response to predictable variations in environmental conditions, allowing this species to reproduce in temperate regions with marked seasonality in water temperature and plankton productivity.     

Increase in respiratory cost at high growth temperature is attributed to high protein turnover cost in Petunia x hybrida petals

It is widely believed that turnover of nitrogenous (N) compounds (especially proteins) incurs a high respiratory cost. Thus, if protein turnover costs change with temperature, this would influence the dependence of respiration rate on growth temperature. Here, we examined the extent to which protein turnover cost explained differences in N-utilization costs (nitrate uptake/reduction, ammonium assimilation, amino acid and protein syntheses, protein turnover and amino acid export) and in respiration rate with changes in growth temperature. By measurements and literature data, we evaluated each N-utilization cost in Petunia x hybrida petals grown at 20, 25 or 35 degrees C throughout their whole lifespans. Protein turnover cost accounted for 73% of the integrated N-utilization cost on a whole-petal basis at 35 degrees C. The difference in this cost on a dry weight basis between 25 and 35 degrees C accounted for 75% of the difference in N-utilization cost and 45% of the difference in respiratory cost. The cost of nitrate uptake/reduction was high at low growth temperatures. We concluded that respiratory cost in petals was strongly influenced by protein turnover and nitrate uptake/reduction, and on the shoot basis, C investment in biomass was highest at 25 degrees C.     

建立金线莲原球茎悬浮体系生产次生代谢产物

研究植物激素浓度和培养周期对金线莲原球茎悬浮培养生长及其代谢产物积累的影响,以增加金线莲悬浮培养的生长量,提高次生代谢产物的生产。结果表明,MS培养基添加S-3307 1.0mg/L,6-BA0.5mg/L和3%的蔗糖适合总生物量的生长(214.45g/L,FW和18.23g/L DW)。而MS培养基添加S-3307 1.0mg/L,6-BA 3.0mg/L和5%的蔗糖,总黄酮,总酚和多糖的干重(5.43mg/g,2.87mg/g和243.23mg/g)达到最大化。研究原球茎悬浮培养过程,发现经过7个星期培养就能获得最大的生物质总量(225.98 g/L的FW和18.53 g/L的DW)、总黄酮干重(5.09mg/g)和总酚干重(2.04mg/g),而多糖生产达到其峰值(229.36mg/g干重)是在培养后5个星期。     

Effect of temperature and sex on growth patterns in nymphs of the mayfly Hexagenia hilineata in the laboratory

SUMMARY. Eggs collected from Hexagenia bilineata females were successfully reared in the laboratory at temperatures of 15, 20, 25 and 30°C. Eggs did not hatch at 10°C and although hatching was successful at 35°C, all nymphs at this temperature died while in early instars.
Survival of nymphs between the approximate size interval of 4–14 mm showed a significant decrease with increased temperatures. Nymphs at 15°C, however, generally did not survive transformation to the subaduit stage.
The growth pattern of individual nymphs was well described by a logistic curve at most temperatures. Furthermore, growth pattern was significantly affected by both temperature and sex.
Rate of development from oviposition to first emergence increased with increasing temperatures in a linear fashion between 15 and 30°C. The relationship was equally well described by a hyperbolic equation and a power-law equation. By extrapolation from the hyperbolic equation, the lower threshold temperature for development was estimated to be 10.1°C3.1°C. The degree (°C)-days required for development from oviposition to first emergence was calculated to be 2337 days with 95% confidence limits of 2045–2727 days under laboratory conditions.