Fresh Weight Gain Research Articles

Use of the Greater Duckweed as feed for the Tilapia fish

The fresh weight gain of the Nile tilapia individuals reared on different feeds for 21 days occurred in the order: conventional feed (65%) > conventional feed and duckweed powder in equal proportion (37%) > duckweed powder (09%). The conventional feed and duckweed powder were insignificantly different from each other in protein and phosphorus, but significantly different (P<0.05) in fat, total ash and calcium contents. The tilapia individuals reared on the mixture of the conventional feed and duckweed powder had significantly (P<0.05) highest concentration of proteins (50.3%) than those reared on either conventional feed (45.34%) or duckweed powder (45.79%) alone.

ThNAC13, a NAC Transcription Factor from Tamarix hispida, Confers Salt and Osmotic Stress Tolerance to Transgenic Tamarix and Arabidopsis.

NAC (NAM, ATAF1/2, and CUC2) proteins play critical roles in many plant biological processes and environmental stress. However, NAC proteins from Tamarix hispida have not been functionally characterized. Here, we studied a NAC gene from T. hispida, ThNAC13, in response to salt and osmotic stresses. ThNAC13 is a nuclear protein with a C-terminal transactivation domain. ThNAC13 can bind to NAC recognized sites and calmodulin-binding NAC (CBNAC) binding element. Overexpression of ThNAC13 in Arabidopsis improved seed germination rate and increased root growth and fresh weight gain under salt or osmotic stress. Transgenic T. hispida plants transiently overexpressing ThNAC13 and with RNAi-silenced ThNAC13 were generated for gain- and loss-of-function experiments. Following exposure to salt or osmotic stress, overexpression of ThNAC13 induced superoxide dismutase (SOD) and peroxidase (POD) activities, chlorophyll and proline contents; decreased the reactive oxygen species (ROS) and malondialdehyde levels; and reduced electrolyte leakage rates in both transgenic Tamarix and Arabidopsis plants. In contrast, RNAi-silenced ThNAC13 showed the opposite results in transgenic Tamarix. Furthermore, ThNAC13 induced the expression of SODs and PODs in transgenic Arabidopsis. These results suggest that ThNAC13 improves salt and osmotic tolerance by enhancing the ROS-scavenging capability and adjusting osmotic potential.

Nymph and Adult Biology of Euschistus cornutus Dallas: a Potential Soybean Pest in the Neotropics.

Laboratory studies with Euschistus cornutus Dallas indicated that nymphs complete development when feeding on green bean, Phaseolus vulgaris L. pod, on soybean, Glycine max (L.) Merrill pod, and on raw shelled peanut, Arachis hypogaea L., but not on fruit (berry) of privet, Ligustrum lucidum Ait. Total mortality was lower on green bean pod (45%), and higher on soybean pod and peanut raw (75 and 80%, respectively). Nymph developmental time was significantly longer for females feeding on green bean pod (37.4days) than on soybean pod (27days); a single data was observed on peanut raw (32days). Males showed no significant differences in total nymph developmental time among foods (31.3 to 33.0days). At adult emergency, fresh body weight of females (52.2 to 68.5mg) and males (61.9 to 71.3mg) did not show statistical differences among foods tested nor between genders. Survivorship of E. cornutus adult after 50days was greater on peanut raw than on green bean or soybean pod; on privet berry, the majority of males and females (>80%) were dead after 20days. The reproductive performance data was, in general, greater on peanut raw than on green bean or soybean pod; on privet fruit, no female laid eggs. Fresh body weight gain occurred on all foods, except on privet berry, on which adults lost weight over time. Records of specimens from insect collections in Brazil indicated that E. cornutus occurs in the Southeast and South regions (19° to 31° S latitude). The most common host plant is soybean, suggesting a potential pest status of this stink bug on this crop in the future.

Greenhouse and in vitro screening of sweetpotato genotypes for drought tolerance

Breeding sweetpotato [Ipomoea babatas (L.) Lam] for drought tolerance requires inexpensive, reproducible and high throughput screening systems. The objective of this study was to apply greenhouse and in vitro techniques to select drought tolerant sweetpotato genotypes. Greenhouse and in vitro experiments were established at Rubona Research Station of the Rwandan Agricultural Board using 54 sweetpotato genotypes. Genotypes were evaluated in the greenhouse using four levels of water regime [control, drought stress imposed by withholding water for one, two or three month(s)], while in vitro tests were carried out using four treatment solutions [control or basic culture medium (0 M), control supplemented with 0.2, 0.4 or 0.6 M sorbitol]. In the greenhouse study, data collected included: soil water potential (ψ w), weights of storage root, biggest storage root and vines, dry matter content (DMC) of storage root and vine and water content (WC) of vines. Whereas ψ w of culture media, fresh weight gain (FWG), DMC and WC were recorded during the in vitro experiment. In the greenhouse test, ψ w of drought stressed treatments varied from-1.94 to-0.05 MPa and showed an increased trend with prolonged drought stress. The control treatment showed ψ w ranging between-0.02 to 0 MPa. During the in vitro experiment, the mean ψ w were-0.07, -0.81, -1.35 and-1.73 MPa for control, 0.2, 0.4 and 0.6 M sorbitol treatments, respectively. Under greenhouse condition, genotype by water regime, genotype and water regime had significant effects (P≤0.01) on yield and yield related traits. Genotypes showed significant differences between the control and drought stress imposed for one month. Under in vitro test, the control and 0.2 M sorbitol treatments were not significantly different in the FWG. However, the control treatment was significantly different from 0.4 and 0.6 M sorbitol concentrations. Positive correlations were observed between vine yield and FWG; and between total biomass and FWG, during greenhouse and in vitro studies, respectively. Overall, genotypes 2005-146, 4–160, 8–1038, Kemb 37, Kwezikumwe, Purple 4419, NASPOT 9, Nsasagatebo, Karebe, 440037, Mwanakumi, 97–062 and Matembere were selected with comparatively high drought tolerance using the two screening procedures. The selected genotypes are useful genetic resources to breed sweetpotatoes for drought tolerance.

Oil accumulation in soybean seeds grown in vitro and in vivo

The soybean seed presents around 20% of oil and 40% of protein. These levels, during the filling of the seeds, can be influenced by environmental conditions, where are produced changes on its biochemistry composition. The higher temperatures promote the accumulation of protein, and the moderate temperatures favor the oil accumulation. Under in vivo growing conditions the control of these factors is difficult. The in vitro procedure can help the research, because the seed can be isolated from the mother plant in controlled environment. The objective of this experiment was to evaluate the oil content of BRS184 and BRS282 in vitro and in vivo . The in vivo procedure, occurred in the greenhouse, with 3plantsper potand seed collectionin R8, and in vitro procedure, developed in the laboratory, where the immature seeds were taken from the mother plant in R5 stage, cultured with a liquid culture medium containing 20 mM, 40 mM and 60 mM glutamine, with a constant agitation, during eight days at 25 ± 0.2 °C, and sucrose concentration of 204.5 mM. After the in vitro cultivation time for, the fresh weight gain of the seeds was evaluated, and after both experiments, was determined by the oil content for cultivation in R5, and R8. The accumulation of oil in soybean seeds presents a complex interaction, ranging between the genotype and the environmental conditions, under in vivo and in vitro cultivation. There is a positive correlation between production and oil content in seeds.

Monitoring of cell wall modifications during callogenesis in Stylosanthes guianensis (Fabaceae) under salt stress conditions

Callogenesis was induced from Stylosanthes guianensis (Aubl.) Sw. cv. CIAT-184 hypocotyl explants cultured in the presence of different concentrations of NaCl. Whereas calluses formed at 50 mM NaCl did not show significant changes, concentrations in the range of 100-250 mM NaCl influenced callus formation and sur- vival. The concentrations which reduced the callus for- mation and survival by 50 % with respect to the controls (I50) were 190 and 225 mM NaCl, respectively. Callus growth was also affected being 160 mM NaCl the con- centration that reduced the fresh weight gain in 50 %, in comparison to the control. The cell walls of calluses formed at higher NaCl concentrations showed a lower cellulose content, which was accompanied by an increase in protein, phenolics, and esters, as revealed by Fourier transform infrared spectroscopy. These overall cell wall modifications were accompanied by the formation of cell wall appositions enriched with homogalacturonan and rhamnogalacturonan components, and also with an increase of arabinogalactan proteins in cell walls. These results evidence the ability of cells to adjust the cell wall com- position under salt stress conditions, as part of the strategy to sustain their growth in such environment.

The impact of different soils and wastewater on castor bean (Ricinus communis L.) growth

The oilseed plant castor bean (Ricinuscommunis L.) has many applications in medicine, industry and agriculture. This study aims to evaluate the growth of castor bean on different soils as affected by wastewater (sewage effluent) irrigation. Thus, castor bean seeds were sown in six different soils (sandy soil - sandy soil + compost - polluted soil - clay soil - calcareous soil - saline soil) and irrigated using equal amounts of sewage effluent. The physical and chemical properties of the soils used and the chemical constituents of sewage effluent were investigated. The results showed that the highest percentage of germination of castor bean seeds (96.6%) were achieved in the clay as well as sandy soil with added compost, followed by sandy soil (92.2%). On the other hand the lowest germination percentages were shown with the seeds sown in calcareous soil (50.3%) and saline soil (30.3%). The time duration required for the radical protrusion was also shortest (quick germination) and longest in the polluted, calcareous, and saline soils. There has been also a marked impact on the plant growth, fresh weight and dry weight gain of, where highest values were shown with the plants cultivated in clay soils followed by sandy soil with added compost. These plants exhibited in addition best criteria (weight, length, width). Thus, the results obtained confirmed the ability of castor beanto grow in different types of soils under irrigation by sewage effluent.

Response of storage duration, harvest stages and polymeric packaging films on post harvest life of gladiolus cut spikes cv. White Prosperity

A study was conducted on response of storage duration, harvest stage and polymeric packaging film on modified atmosphere storage of gladiolus cut spikes cv. White Prosperity. The cut spikes were harvested at two distinct stages of floret development, i.e., S1- when 1–2 florets showed colour, S2 when- 4–5 florets showed colour, packed in various wrapping material and stored for four storage duration levels. Polymeric sleeves exerted varying effect on keeping quality of spikes. S1- spikes exhibited lower vase-life than S2- spikes. Vaselife was maximum in polypropylene-100 and minimum in low density polyethylene -200 gauge sleeves. The keeping quality of unpackaged cold stored cut spikes was highly deteriorated, which decreases with increase in refrigerated storage duration. An ideal level of higher CO2 (4.30%), lower level O2(10.64%) and C2H4 (0.50 ppm), respectively were recorded at 7 days storage duration with the spike harvested at 4–5 florets show colour and packed in polypropylene -100 guage interaction (D2S2P3). The spikes stored at D2S2P3 level also showed higher number of florets opened at a time (3.21), gain in fresh weight (6.01%), longevity of floret (3.46 days), opened florets per spike in vase (8.40), second floret diameter (10.42 cm), vase-life (8.40 days) and water uptake (67.86 ml), which continued to decrease with increase in storage duration. Hence, 7 days storage duration with 4–5 florets show colour on spike (S2) and packed in polypropylene -100 guage sleeves were found most suitable for post-harvest life under modified atmosphere storage of gladiolus.

In Vitro Analysis of Taurine as Anti-stress Agent in Tomato (Solanum Lycopersicum)-Preliminary Study.

Taurine has many essential biological functions in animal cells. In plants, taurine does not appear to play a major physiological role. The potential role of taurine has not been extensively studied in higher plants to date. In this study, anti-stress potential of taurine was analyzed in vitro according to the vital signs of tomato explants (callus formation and shoot regeneration potential) at different taurine concentrations. After 3 weeks of culture in vitro, the explants were subjected to stress conditions caused by hydrogen peroxide or NaCl. The explants were then transferred to media containing taurine. Assessments were made by measuring the time to callus and shoot formation, the number of shoots formed, and the fresh weight (FW). Callus and shoot development was considerably delayed in the stress-induced explants. When they were cultured in the media containing taurine, however, the total number of shoots was less affected by stress compared to the taurine-free control. In terms of the time to callus formation, taurine exerted a positive effect on the tomato explants undergoing various stresses decreasing the length of time required until induction. Taurine-treated calluses showed a gain in FW, comparable to the gain of the non-stressed controls. In conclusion, taurine had a positive impact on the explants affected by the two stress agents. It strongly indicates that taurine can be used as an anti-stress agent not only for animal systems, but also for plants in general.

Phosphorus solubilizing bacteria and rice straw biochar consequence on maize pigments synthesis

To determine the effect of phosphorus solubilizing bacteria and biochar various application rates on fresh and dry weight, photosynthetic and accessory pigments production in maize plants a pot experiment was conducted. There were 4 doses of Rice straw biochar (0, 1, 2 and 3%) with and without phosphorus solubilizing bacteria (PSB) making 8 treatments with 4 replications (CRD). After 40, days of seeds sowing plants were harvested and pigments (chlorophyll a, chlorophyll b, total chlorophyll, lycopene, carotenoids and anthocyanin) analysis was done in maize shoot as well as pH, EC (µS/cm) and OM (%) in post harvested soil. Results indicated a significant increase in soil pH, EC and OM due to addition of 1%, 2% and 3% rice straw biochar (RSB) which helps in enhancing the activity of photosynthesis by providing nutrients. PSB significantly reduced the pH of soil through organic secretions and OM by decomposition. Interactive effect of PSB and biochar was significant for chlorophyll (a, b, total) while it changed the lycopene, carotenoids and anthocyanin synthesis non significantly. In case of lycopene the maximum synthesis was noted in control (B0P0) treatment plants. The plants cultivated in a soil having treatment 3% rice straw biochar + PSB showed maximum production of pigments as compared to the control (B0P0) treatment plants. The main and interactive effects of RSB as well as PSB were significant on maize plants fresh and dry weight. An increasing rate of biochar enhanced the fresh and dry weight gain in combination with PSB.

Influence of different carbon sources on in vitro induction of anthocyanin pigments in callus cultures of petunia (Petunia hybrida)

Anthocyanins are naturally occurring compounds that impart color to fruits, flowers, vegetables, and plants. They are probably the most important group of visible plant pigments besides chlorophyll pigments. Apart from imparting color to plants, anthocyanins also have an array of health-promoting benefits, as they can protect against a variety of free radicals through a various number of mechanisms. Development of an efficient tissue culture system for commercial production of anthocyanins requires an integrated approach through manipulation of various media constituents. The effect of varied concentrations of different carbon sources on anthocyanin production in callus cultures of Petunia hybrida cv Bravo Blue was studied. Explants from young leaves were cultured on Murashige and Skoog (MS) medium supplemented with MS + IBA (19.6 µM) + Kin. (4.65 µM) + AdS (81.45 mM), 3% sucrose and 0.7% agar. Among the various carbon sources tested, incorporation of Glucose at 5% was found to have earliest pigment induction with maximum response coefficient with highest pigment content (1.36 ± 0.012 CV/g FCW). Highest gain in fresh cell weight was noticed with the addition of sucrose 5% (3.96 ± 0.06 g). When MS medium was supplemented with different concentrations of Galactose, the explants failed to respond.

Production of guaianolides in Agrobacterium rhizogenes - transformed chicory regenerants flowering in vitro

Chicory (Cichorium intybus L.) is rich in bitter sesquiterpene lactones, mainly guaianolides: lactucin, 8-deoxylactucin, lactupicrin and their 11(S),13-dihydroderivatives—compounds recognized for their antimicrobial and anti-cancer effects. In vitro plant tissue culture, and particularly Agrobacterium rhizogenes—generated hairy root (HR) cultures, have many advantages as systems for production of valuable secondary metabolites. Although chicory HRs grow better than control culture, having nearly 60 times greater fresh weight gain, they do not contain a higher content of guaianolides than wild type (wt) roots. Thus we have established in vitro system comprised of wt root and HR cultures, and wt and transformed regenerated plants of the same age, in rosette and flowering stage, in order to study the effects of transformation, organogenesis and flowering on guaianolides production. Both regeneration and flowering in vitro were spontaneous, so the results were not influenced by exogenous growth regulators. Some of the transformed clones grew better, but all flowered earlier in comparison to wt plants. Floral transition increased guaianolides content in both roots and leaves of transformed, but not of wt plants. Expression of RolC oncogene correlated with floral transition and with guaianolides accumulation. We propose A. rhizogenes—transformed plants at the flowering stage as an alternative source of free guaianolides, where, in contrast to HRs, entire plants can be used for the extraction.

A novel ethylene-responsive factor fromTamarix hispida, ThERF1, is a GCC-box- and DRE-motif binding protein that negatively modulates abiotic stress tolerance inArabidopsis

Ethylene-responsive factor (ERF) family is one of the largest families of plant-specific transcription factor that can positively or negatively regulate abiotic stress tolerance. However, their functions in regulating abiotic stress tolerance are still not fully understood. In this study, we characterized the functions of an ERF gene from Tamarix hispida, ThERF1, which can negatively regulate abiotic stress tolerance. The expression of ThERF1 was induced by salinity, PEG-simulated drought and abscisic acid (ABA) treatments. ThERF1 can specifically bind to GCC-box and DRE motifs. Overexpression of ThERF1 in transgenic Arabidopsis plants showed inhibited seed germination, and decreased fresh weight gain and root growth compared with wild-type (WT) plants. In addition, the transcript levels of several superoxide dismutase (SOD) and peroxidase (POD) genes in transgenic plants were significantly inhibited compared with in WT plants, resulting in decreased SOD and POD activities in transgenic plants under salt and drought stress conditions. Furthermore, the reactive oxygen species (ROS) levels, malondialdehyde (MDA) contents and cell membrane damage in ThERF1-transformed plants were all highly increased relative to WT plants. Our results suggest that ThERF1 negatively regulates abiotic stress tolerance by strongly inhibiting the expression of SOD and POD genes, leading to decreased ROS-scavenging ability.

Effect of activated charcoal on multiplication of African yam (Dioscorea cayenensis-rotundata) nodal segments using a temporary immersion bioreactor (RITA®)

In this study, we compared the growth of Dioscorea cayenensis-rotundata (African yam) nodal segments, using semisolid medium in test tubes and liquid medium in 1-L Recipient for Automated Temporary Immersion (RITA®) temporary immersion bioreactors (TIB), and the application of various culture parameters. The addition of activated charcoal (AC) had a positive effect on the growth of nodal segments, both in semisolid medium and in liquid medium in RITA® bioreactors. After 2 mo culture in the presence of AC, plantlets were 6.4–6.6 cm long compared to 3.2–3.8 cm in absence of AC, with no significant difference observed between the culture systems. In the range of inoculation densities tested (5–20 nodal segments per RITA® bioreactor), there was no effect on the number of buds produced per nodal segment, the moisture content of plantlets (fresh weight basis), or on net fresh weight gain. By contrast, the individual leaf surface area of plantlets decreased in line with increasing inoculation density. Among the range of benzylaminopurine (BAP) concentrations tested (0–17.6 μM), 0.44 μM induced the highest number of buds (3.8 buds per nodal segment) in the TIB. However, comparable numbers of buds could be produced with media devoid of BAP, either by increasing the frequency of 1-min daily immersion cycles in RITA® bioreactors from one every 12 h to one every 4 h or by using semisolid medium containing AC.

Effect of Photoperiod and Temperature on Nymphal Development and Adult Reproduction ofPiezodorus guildinii(Heteroptera: Pentatomidae)

The effect of photoperiod and temperature on the biology of nymphs and adults of Piezodorus guildinii (Westwood) was studied in the laboratory. Four different conditions were tested (14:10, 12:12 and 10:14 h L:D at 25 °C, and 10:14 h L:D at 20 °C), at 80 ± 10% RH. The shortest nymph development time was recorded at 14:10 h L:D (25 °C) (21.5 days) and the longest at 10:14 h L:D (20 °C) (42 days). The highest nymph mortality rate was recorded at 10:14 h L:D (20 °C) and the lowest at 14:10 h L:D (25 °C) (84.5 vs. 24.2%). Newly emerged females reared at 14:10 h L:D (25 °C) were heavier than those of the remaining treatments. Fresh body weight gain (mg) occurred only during the 1st week of adult life. Adult survivorship was highest at 10:14 h L:D (20 °C) and lowest at 14:10 h L:D (25 °C). Total longevity was shortest when adults were held at 14:10 h L:D (25 °C) and longest at 10:14 h L:D (20 °C) (38.6 vs. 98.8 days). The maximum percentage of ovipositing females occurred at 14:10 h L:D (25 °C) and the minimum at 10:14 h L:D (20 °C). Females maintained at 14:10 h L:D (25 °C) and 12:12 h L:D (25 °C) produced similar and greater number of egg masses than females at 10:14 h L:D (25 °C) and 10:14 h L:D (20 °C). The number of eggs/female was the greatest at 14:10 h L:D (25 °C) and the lowest at 10:14 h L:D (20 °C) (196.2 vs. 21.7 eggs/♀). Egg viability was similar under different photophases at 25 °C, while significantly reduced at 10:14 h L:D (20 °C) (54 vs. 4.1%). The longest egg incubation period was recorded at 10:14 h L:D (20 °C) and the shortest at 14:10 h L:D (25 °C) (7 vs. 4.1 days). These laboratory results suggest that P. guildinii does not reproduce during the time its preferred host soybean is unavailable at latitude 30°–35° S, which corresponds approximately to the conditions tested at 10:14 h L:D (20 °C).

Nymph and Adult Biology on Cultivated and on Non-Cultivated Plants and Seasonal Phenology on Wild Plants of the Neotropical Stink Bug, Euschistus paranticus Grazia (Hemiptera: Heteroptera: Pentatomidae)

Laboratory studies were conducted to evaluate nymph survivorship, developmental time, and fresh body weight at adult emergence, and adult survivorship, total longevity, reproduction, and fresh body weight gain of the Neotropical stink bug, Euschistus paranticus Grazia (Heteroptera: Pentatomidae). In the field, a one-year weekly survey was carried out on the wild plants, Scutia buxifolia Reissek (Rhamanaceae) and Prunus myrtifolia (L.) Urb. (Rosaceae) in Passo Fundo, RS, Brazil (28°15′S latitude; 52°24′W longitude). Results indicated that nymph mortality was very high (range 87-100%) and on only two (green bean pod + raw shelled peanut and green bean pod alone) out of the nine foods, nymphs were able to complete development. Nymph developmental time (2 nd to 5 th stadia) took ≈ 33 days on green bean pod + peanut seed, and ≈ 54 days on green bean pod. Adults E. paranticus fed pods of green bean, raw shelled peanut, mature seed of soybean, and leaf of S. buxifolia in the laboratory showed a total longevity of ≈ 40 to 55 days; 50% females oviposited; the pre-oviposition period was 18.9 days; number of egg masses/female was 9.3; mean total number of eggs/female was 103.6, and their viability was 55.6%. Females were heavier than males. E. paranticus was intercepted mostly during spring-summer on S. buxifolia, and only occasionally on P. myrtifolia.

몇 가지 재배조건이 물가양털이끼와 쥐꼬리이끼의 생육에 미치는 영향

This study was carried out to develop the proper cultivation methods of Brachythecium rivulare and Myuroclada maximowiczii which showed high-value for the interior landscaping and potting. Growth of two moss species cultivated in the compost covered with cloth was vigorous compared to that grown in containers only using cloth or compost, and their harvesting processes were easier. The growth and harvest easiness of mosses cultivated in compost were great rather than in bark or peatmoss. Compared to division, the spray of crushed mosses using mixer was effective for both gametophyte generation and their harvesting processes. In addition, the optimum inoculum for each container (27×17×3 cm) was 2.0 g in B. rivulare and 4.0 g in M. maximowiczii. Overall growth of B. rivulare treated with nutrient solution (N:P:K=20:20:20) was inhibited compared to control, fresh-weight gain was reduced toward the higher concentration. But fresh-weight gain of M. maximowiczii was the highest with 0.25 g·L -1 treatment. Therefore, adequate moisture supply, after spraying crushed mosses (2.0 and 4.0 g each) in the compost covered with cloth, were the appropriate cultivation methods for B. rivulare and M. maximowiczii. Nutrient solution treatment with low concentration, during the cultivation period, would be the proper way only for M. maximowiczii.

Desenvolvimento do maracujá doce em Viçosa, Minas Gerais

Foram avaliadas as mudanças físicas, químicas e fisiológicas ocorridas durante o desenvolvimento do maracujá doce, da antese até o completo amadurecimento na planta. Os frutos apresentaram formato ligeiramente oblongo, padrão de desenvolvimento sigmoidal simples e padrão climatérico para a respiração. O desenvolvimento do fruto foi dividido em três fases: divisão celular até 4,70 dias após a antese (daa), expansão celular de 4,70 daa até 28,94 daa e maturação, de 28,94 daa a 91 daa. Na primeira fase, há pouco incremento nas dimensões do fruto, altas taxas respiratórias, crescimento acelerado da espessura do pericarpo e coloração do pericarpo verde-claro. Na fase seguinte, há intenso desenvolvimento das dimensões do fruto, ganho acelerado de massa da matéria fresca e coloração do pericarpo verde-intenso. Na terceira fase, há tendência à estabilização das dimensões, desenvolvimento de polpa acentuado, o teor de sólidos solúveis aumenta, os teores de vitamina C e acidez titulável diminuem. O pico do climatério foi registrado aos 63 daa. No último dia de avaliação, aos 91 daa, a polpa (suco + sementes) representava 24,46% da massa da matéria fresca total do fruto, o pericarpo respondia por 74,10% e as sementes isoladas, por 3,14%.

Comparative study of effects of table sugar, laboratory grade sucrose and mannitol on growth of banana plantlets under in vitro conditions

A study was conducted to investigate effects of table sugar, laboratory grade sucrose and mannitol on growth of banana plantlets under in vitro conditions. Plantlets of banana of Injogo variety were grown on Murashige and Skoog (premixed) basal medium with vitamins (4.4g x l-1) supplemented with 1ìM benzylaminopurine and 1ìM indole acetic acid. The experiment was executed in two phases. In the first phase, 30g x l-1 of laboratory grade sucrose, table sucrose and mannitol was used with no sugar as a control treatment. In the second phase of the experiment, the quantity of carbohydrates was reduced to 15g x l-1. Data on growth rate and fresh weigh gain was collected. After four weeks, plants grown on the culture medium with laboratory grade sucrose showed consistently higher growth rate and more gain in fresh weight (2.395 and 1.039g respectively for 30 and 15g of sugar per litre of culture medium) as compared to the other treatments (1.397, 0.110 and 0.373g for 30g of sugar per litre of culture medium, and 0.767, 0.355 and 0.638g for 15g of sugar per litre of culture medium, respectively for the table sugar, mannitol and control). The plantlets grown on the culture medium with mannitol showed the lowest gain of fresh weight. This indicates that mannitol is a poor source on energy for banana plantlets. This study indicated a possibility of replacing the laboratory grade sucrose by the table sugar without significant loss in quality and growth so as to reduce the production cost of in vitro plantlets of banana.

Seasonal Variation in Growth, Leaf Physiology and Fruit Development in Kinnow, a Mandarin Hybrid

In the early bearing stage of Kinnow, the magnitude of vegetative growth was maximum in spring flush (47.08%) followed by in the rainy season flush (42.07%), whereas, the winter fall flush bore only minor flush of the annual vegetative growth (10.85%). Similarly, the spring flush leaves showed the minimum values of leaf sclerophylly i.e. leaf area, leaf fresh and dry weight, specific leaf weight, density of foliar tissue and leaf tissue succulency as compared to rainy and winter fall flushes leaves, implying that spring season growth most serves as a sink to developing fruits. Growth of the Kinnow fruit in phase 1st which last for one month up to April is primarily due to the increase in peel thickness which contributes about 70% of the fruit radius. In phase 2nd, growth of the fruit is due to the increase in pulp tissue thickness contributing 80% of the fruit radius, increased fruit fresh weight, moisture content and decreased peel thickness up to September. Major gain in fresh weight of the fruit is from May-October, contributing 80.14% of the total fruit weight. Thereafter, phase 3rd of maturation and ripening starts with comparatively decreased rate of increase in fruit weight and size, and slightly increased rate of dry weight, peel thickness and reduced moisture percentage. This study will be further helpful in increasing the input efficiency of resources for improving fruit size and reducing fruit drop in kinnow (K) mandarin.