Seed germination and seedling growth of Pycnanthus angolensis (Welw.) Warb., African false nutmeg

This study investigated the germination behavior and seedling growth of Pycnanthus angolensis seeds.The germination study was carried out in the laboratory and included pretreatment studies and observation of the seed-germination process.For each treatment,three replications of 20 seeds were sown in a transparent plastic germination box(12cm×22cm×5cm)lined with moistened filter paper at room temperature.To monitor seedling growth,seedlings were transplanted into pots filled with topsoil and laid out in a completely randomized design.Ten seedlings replicated thrice were measured monthly;and the shoot height,leaf area,and root length,as well as the fresh and dry weights of the seedlings,were recorded.Results showed that mechanically scarified seeds exhibited the significantly highest germination percent(83.33%,P<0.005),followed by control seeds(70.83%),whereas seeds treated with 98%sulphuric acid(H2SO4)displayed the lowest germination percent(1.67).The endospermous seeds exhibited cryptogeal germination,while seeds stored for a month(with or without arils)failed to germinate.During seed germination,radicle protrusion continued with a pseudo-opening of the root,through which the brownish cotyledonary petiole was emitted,thus releasing the plumule at the posterior position.Moreover,P.angolensis exhibited a slow growth rate,attaining a shoot height of 73 cm within a year.The highest positive change in leaf number and area was recorded in the fourth month,a period during which the least change in shoot height occurred.The study concluded that mechanical scarification of the seeds ensured significant and faster germination than chemical scarification or no treatment at all.Additionally,P.angolensis displayed a cryptogeal germination,with the seedling growth of the tree species observed to be slow.

Preliminary Study on Tissue Culture Technique of Brassica campestris L. ssp. chinensis (L.) Makino var. utilis

In order to establish a rapid propagation system for Brassica campestris L. ssp. chinensis var. utilis, the anther and cotyledon-cotyledonary petioles were used as explants to conduct tissue culture research. The results showed that not bloomed flower buds with higher styles than petals were appropriate for anther cul- ture. Moreover, most microspores were at the mid-late uninucleate stage at that time. The pollen germination rates of Brassica campestris L. ssp. chinensis var. u- tills were low and the germination rates in autumn and winter were higher than that in summer. The induction medium of anther callus of Brassica campestris L. ssp. chinensis var. utilis was MS＋1.0 mg/L KT＋1.0 mg/L 2, 4-D＋3% sugar＋6 g/L agar＋ 8% coconut milk and the induction media of adventitious bud were MS＋2.0 mg/L 6-BA＋ 0.5 mg/L NAA＋I.0 g/L activated carbon＋2% sugar＋6 g/L agar or MS＋2.0 mg/L ZT＋ 0.5 mg/L IAA＋0.5 g/L AgNO3＋1.0 g/L activated carbon＋2% sugar＋6 g/L agar. The induction percentage of adventitious bud by anther culture was 36.7%. Browning phenomenon appeared during the culture of adventitious bud and regeneration plant could not be formed. The plant regeneration rate reached 80% when cotyledon- cotyledonary petioles were used as explant.