Mushtaque Ahmed Jatoi

In vitro callus induction protocol for Leptadenia pyrotechnica using various explants

An efficient protocol has been developed for a rapid callus induction inxa0Leptadenia pyrotechnica.xa0Nodal, internodal and pod explants from mature plant ofxa0L. pyrotechnicaxa0were cultured after surface sterilization on Murashige and Skoog medium supplemented with plant growth regulators (PGRs) cytokinins and auxins individually and with various combinations. Nodal segments proved the best explants (90% callus induction) compared with internodal and pod explants (5% and no callus induction respectively). Different treatments were employed for surface sterilization of explants revealing that combination of sodium hypochlorite (NaOCl2) and mercuric chloride (MC) were found significant. Minimum contamination (7%) occurred at 30% NaOCl2xa0+xa02 g/L MC, while 80% occurred at 30% NaOCl2xa0+xa01 g/L MC. The nodal segments cultured on MS medium supplemented with 0.5 mg/L NAA that produced maximum callus (90%) within four weeks. It was followed by 60% callus induction at 5 mg/L NAA + 2.5 mg/L benzyl-adeninexa0 (BA) and 30% at 10 mg/L 2,4-D + 3 mg/L 2ip + 3 g/L activated charcoal (AC), while only 20% appeared at control (without hormone application). This is the first successful attempt to establish consistent callus formation protocols from nodal stem segments ofxa0L. pyrotechnica. This study may contribute in conservation management of this native plant species found especially in the deserts of Pakistan. n n xa0 n n Key words:xa0Callus induction,xa0Leptadenia pyrotechnica,xa0plant growth regulators, cytokinins, auxins.

Biodiversity and Conservation of Date Palm

Date palm is one of the main horticultural crops of the ancient and recent world and an important source of food. Geographical distribution between 24° and 34°N latitude is considered as the main biodiversity centers of date palm distribution. There are about 5000 date palm cultivars besides countless varietal strains throughout the world, but every date-producing country has only few top commercial cultivars being cultivated and exported in all over the world. Commercial laboratories of tissue culture-derived date palm have contributed in spreading the cultivation and exchange safely cultivars of date palm worldwide. However, the date palm diversity is nowadays facing crucial problems such as Bayoud disease and red palm weevil (RPW) besides water shortage, urban settlement and disruption, rapid soil and genetic erosion and uncontrolled commercial exploitations of cultivating only elite cultivars. Numerous efforts have been made for in situ/on-farm conservation methods though effective but quite expensive and hence found only on small scale. The ex situ conservation methods of seed and DNA storage are not applicable due to their recalcitrant seeds and heterozygosity nature. Nevertheless, the in vitro conservation of date palm in form of shoot tips, axillary buds, embryos, and callus for longer periods by using slow growth or cold storage in vitro cultures and cryopreservation techniques is promising but might undergo somaclonal variation and less viability after thawing. The maintenance of field gene banks is found to be highly effective for conservation and providing the long-term preservation but relatively expensive and requiring huge space.

Colouration of Apple cv. ‘Braeburn’ Grown Under Anti-Hail Nets in Croatia

Abstract Four anti-hail and anti-insect nets (red, white and yellow anti-hail and Stop Drosophila Normal) were used on apple cv. ‘Braeburn’ grown in northern Croatia in order to evaluate their effect on fruit colouration that was measured with the colorimeter (expressed as: L* – lightness, a* – yellow/blue b* – green/red) on two sides of fruit (“green” side and “red” side), and also they were used in order to evaluate their effect on the coloured surface percentage, apart from their anti-hail and pest damage protection properties. The fruits were harvested on 12th October 2015. Most differences were found between the fruit grown under the white anti-hail net and the fruit grown without the anti-hail net. Colour value “a*” was lower on the red side of the fruit under the white net in comparison with the red net. On the green side, “a*” value was lower and “L*” value was higher under the white net in comparison with control fruit. Different net colour had no influence on total colour difference. Regarding to the colouration, differences among the nets are found in classes 0–25% and 50–75% of skin coloured fruit. The fruit grown under the white nets had the higher percentage of fruit in class 0–25% than those grown without the net. The lower share of fruit in class 50–75% of skin colouration was recorded under the white net than under the red net or in the control fruit. Colouration index was lower in the fruit grown under the white net than in the control fruit. It can be concluded that the white anti-hail net promotes ripening, but at the same time it decreases red colouration. No significant differences in fruit colour have been found in the fruit grown under the red, yellow and Stop Drosophila Normal nets. Some accepted colour parameters such as a*/b* ratio are not appropriate for describing colour changes in ‘Braeburn’ apple in this study.