Vitreous GeO2 response to shock loading

Shock wave profiles in vitreous GeO2 (6.56 Mg/m^3) under planar loading were measured using stress gauges to 14 GPa. New and previous data yield Hugoniot: D=0.974 (km/s)+1.711 u for shocks of 6 to 40 GPa. We show that the phase change from 4- to 6-fold coordination of Ge+4 with O–2 in vitreous GeO2 occurs from 4 to 15 GPa. Hugoniots of vitreous GeO2 and SiO2 are found to approximately coincide if the pressure in SiO2 is scaled by the ratio of SiO2 to GeO2 initial density

Role of Paclobutrazol and Ethephon in Reproductive Growth of 'Allahabad Safeda' Guava (Psidium guajava L.) Plants at Different Spacing

A study on 4-year 'Allahabad Safeda' guava plants was made to assess the influence of Paclobutrazol (PP 333), [(2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4 triazol-1-yl) pentan-3-ol], a gibberellin-inhibitor, and Ethephon [(2-chloroethyl) phosphonic acid], a vegetative growth inhibitor and a ripening promoter, on reproductive growth of plants. Treatments in the form of foliar application at 500 and 1000 ppm were applied consecutively during March 2007 and 2008 on plants at 6m x 2m, 6m x 3m, 6m x 4m and 6m x 5m spacing. Maximum flowering and fruit set was recorded in paclobutrazol treated plants in both rainy and winter crops. Ethephon reduced flower bud density (FBD) and fruit set during both the cropping seasons. However, Ethephon treated plants exhibited slightly higher fruit retention. Ethephon advances fruit maturity by upto a week during rainy season and two weeks during winter season. Paclobutrazol treated plants exhibited significantly higher fruit number, fruit yield, yield efficiency, fruiting density compared to Ethephon treated and control plants. Reproductive growth of plants at wider spacing of 6m x 5m and 6m x 4m significantly improved compared to closer spacings of 6m x 2m and 6m x 3m during both cropping seasons. Plants at wider spacing responded better to Paclobutrazol applications with respect to flowering and fruiting

In vivo development of ovule in seedless and seeded cultivars of grapes (Vitis vinifera L.)- a particular reference to in ovulo embryo culture

Ovule development was examined in the three seedless cvs Perlette, Thompson Seedless, Beauty Seedless and the seeded cv. Anab-e-Shahi, to identify the proper developmental stage of the embryo for in ovulo embryo culture. The number of shrivelled ovules started increasing 20 d post anthesis. At the same time, the number of viable ovules started declining in all the seedless cultivars. Amongst seedless cultivars, the growth of ovules was least in cvs Thompson Seedless and Beauty Seedless. The ovule development was faster in Anab-e-Shahi as compared to all the seedless cultivars. Total number of ovules per berry declined 20 and 30 d post anthesis in cvs Beauty Seedless and Perlette, respectively. Keeping in view the above mentioned parameters, the embryos in seedless cultivars of grapes may be rescued in vitro prior to 20 d post anthesis to obtain plantlets from these abortive ovules.Die Entwicklung der Samenanlagen bei kernlosen und kernhaltigen Rebsorten (Vitis vinifera L.) in vivo im Hinblick auf die Embryokultur in vitroUm das geeignetste Entwicklungsstadium der Embryonen für ihre in-vitro-Kultur zu ermitteln, wurde bei den drei kernlosen Rebsorten Perlette, Thompson Seedless und Beauty Seedless sowie der kernhaltigen Sorte Anab-e-Shahi die Entwicklung der Samenanlagen verfolgt. Die Anzahl geschrumpfter Samenanlagen begann 20 d nach der Anthese anzusteigen. Gleichzeitig setzte bei allen kernlosen Sorten die Abnahme der vitalen Samenanlagen ein. Von den kernlosen Sorten zeigten Thompson Seedless und Beauty Seedless das schwächste Wachstum der Samenanlagen. Bei Anab-e-Shahi entwickelten sich die Samenanlagen schneller als bei den drei kernlosen Sorten. Bei Beauty Seedless und Perlette ging die Gesamtzahl der Samenanlagen 20 bzw. 30 d nach der Anthese zurück. Unter Berücksichtigung der oben genannten Entwicklungszeiten sollten die Embryonen binnen 20 d nach der Anthese in Kultur genommen werden, um aus den später absterbenden Samenanlagen in-vitro-Pflanzen zu gewinnen

In vitro plant regeneration in seedless grapes (Vitis vinifera L.)

Young leaves, shoot apices, nodal and internodal segments from mature field-grown grapevines (Vitis vinifera L.) cvs Thompson Seedless and Perlette were cultured on MS medium containing different concentrations and combinations of NAA, 2,4-D, Kin and BAP. The genotype, nature of explant and chemical composition of medium affected the callusing frequency and type of callus. The media containing auxins produced friable, soft and creamish white to green calli. Such calli turned brown and died within 4-6 weeks. The medium containing BAP or Kin produced green compact and nodular calli. The subculturing of green nodular calli on MS basal medium induced 20.0 and 12.5 % rooting in cvs Perlette and Thompson Seedless respectively. Subculturing of calli on MS medium containing BAP (2 mg/l) resulted in 12.1 % complete plant regeneration in Thompson Seedless, cv. Perlette failed to regenerate. Adventitious shoots developed in 65.4 and 50.0 % of the cases from the in vitro derived leaves of Thompson Seedless and Perlette when cultured on MS medium containing BAP (2 mg/l). More than 85 % of the adventitious shoots of both the cultivars rooted successfully on MS medium containing IBA (1 mg/l)

Response of different Bt cotton (Gossypium hirsutum L.) hybrids to canopy modification practices

A field investigation was carried out to characterize the growth and development of Bt cotton hybrids by detopping and use of plant growth retardants during the rainy (kharif) season of 2011 and 2012. The experimental site had loamy sand soils with normal in reaction. The experiment (split plot) involved three Bt cotton hybrids (MRC 7017, MRC 7031 and RCH 314) in main plots and growth regulation treatments (Mepiquat chloride (MC) @ 300 ppm, 2, 3, 5-tri iodo benzoic acid (TIBA) @ 100 ppm and Maelic hydrazide (MH) @ 250 ppm) in sub plots with four replications. Hybrid MRC 7017 produced significantly higher (p<0.01) seed cotton yield which was attributed to the maximum number of sympodial branches plant-1, total number of flowers and picked bolls plant-1. Application of MC @ 300 ppm, TIBA @ 100 ppm and MH @ 250 ppm reduced plant height, leaf area index and total dry matter accu-mulation than control. Detopping treatment significantly (p<0.01) reduced plant height than control but attained more plant height than all the PGRs. MC @ 300 ppm, TIBA @ 100 ppm and MH @ 250 ppm at 80 days after sowing had beneficial effect on seed cotton yield. Detopping done at 80 days after sowing failed to influence the seed cotton yield dur-ing both the years. The results revealed that foliar application of MC @ 300 ppm yielded more seed cotton by improv-ing the setting percentage and therefore, increased number of picked (open) bolls plant-1 without exhibiting any ad-verse effect on quality traits

Effect of Spacing on Canopy Microclimate, Vegetative Growth and Yield Attributes in Guava (Psidium guajava L.)

The present investigation was conducted to examine the effect of spacing on variation in canopy microclimate, vegetative growth and yield attributes in guava (cv. Allahabad Safeda). Oservations revealed that with wide plant spacing (from 6x2m to 6x4m), interception of solar radiation increased significantly. Similarly, with increase in spacing between plants, mean canopy temperature was need to increase while relative humidity decreased. Plant growth in terms of stock and scion girth, tree spread (N-S) and canopy volume increased with wide plant spacing, while tree height decreased with increase in plant spacing. Number of fruits per plant, yield per plant and fruiting density was higher at 6x5m and least in 6x2m spacing. Wider plant spacing was found to be better owing to maximum absorption of solar radiation and optimum microclimate in the orchard leading to better yield in plants, higher fruiting density and yield efficiency. However, yield/ha was maximum in 6x2m spacing during rainy season and in 6x3m spacing during winter

Influence of Nitrogen and Phosphorus Fertilization on Fruiting and Yield Characteristics in Ratoon Crop of Banana (Musa spp. AAA) Cv. Grande Naine

In ratoon crop of banana cv. Grande Naine, date of shooting could be advanced by 35 days with application of 200g N in 5 splits + 60g P2O5 (86 days), compared to 300g N in 5 splits + 60g P2O5 (121 days). Subsequently, date of harvest also got advanced by 53 days, and fruits were harvested on 9th December in the same treatment. Higher dose of N fertilization delayed shooting and harvesting period, taking 121 days for shooting and 145 days from shooting to harvest in the treatment 300g N (5 split doses) + 90g P2O5. Various N and P treatments affected bunch weight and number of hands per bunch significantly. Although N and P combination-treatments had no significant effect on bunch weight or number of hands per bunch, application of 200g N in 5 splits and 60g P2O5 per plant gave maximum bunch weight (18.11kg) and number of hands per bunch (10.61). Minimum bunch weight (15.37kg) and the least number of hands per bunch (7.08) were obtained with 150g N in 5 splits + 90g P2O5. Hand-weight (2.20kg), number of fingers per hand (19.75), and finger length (20.30cm) was highest with application of 200g N in 5 splits + 60g P2O5 per plant. Least hand-weight (1.64kg), number of fingers per hand (15.77), and finger-length (17.92cm) was recorded with 150g N in 5 splits + 90g P2O5. Bunch weight, number of hands per bunch, hand-weight and number of fingers per hand too was affected significantly with sole application of nitrogen or phosphorus