Abstract
Seeds of Jojoba (Simmondsia chinensis (Link.) C.E. Schneider, collected from its plantation raised by Jojoba Research Station, Bahawalpur, Pakistan, were germinated in garden loamy soil and some of the seed and seedling characteristics were studied. The seeds of Jojoba are chocolate (mahogeny) brown in colour, ovate in shape and non-endospermic provided with a dorsal longitudinal raphe. Testa is thin but hard. A dense creamy-white mat of unicellular trichomes is present over the surface of the seed. The weight of seed averaged to 895.32 ± 11.62 mg varying from 551 to 1155 mg (CV: 12.98%). The seed weight tended to follow normal distribution. Jojoba seedlings appear to resemble the Chisocheton subtype of Vogel (1980). According to the Garwood (1996) scheme Jojoba seedling may be classed as “Crypto-cotylar hypogeal Reserve type”. The embryo is straight. Cotyledons are massive, shortly petiolate succulent, food-laden, creamy white in colour and semi-ellipsoidal in shape. The outer surface of cotyledons is provided with longitudinally running grooves. In one-month old seedlings, shoot was 10.75 ± 1.05 cm and root 12.8 ± 1.8cm long and there were 9.75 ± 1.18 leaves per seedling. There existed variation with respect to leaf shape. The leaves of basal nodes were obtuse apexed, emarginate or round. The leaves of upper nodes were ovate or oblong or elliptic to lanceolate or oblanceolate in shape with acute apex. Venation appeared to be of brachidodromous type as evident by the grooves on the lamina. Stem and leaves densely pubescent. The trichomes of shoot were of two types – a) multicellular uniseriate trichomes of 2-9 (-11) and b) glandular multicellular uniseriate trichomes with apical cell globose. Some trichomes showed meander like cell wall. The shoot of seedling was thickly encrusted with cuticle and wax. The stomata of anomocytic type were the common one. The inner surface of cotyledons had tetracytic stomata. Some stomata with common subsidiary or no subsidiary also existed on stem and leaf. Leaves of Jojoba are amphistomatic. The occurrence of pericytic stoma besides anomocytic one was extremely rare feature on dorsal foliar surface. The average number of stomata was higher on the lower surface (81.91 ± 1.387 per mm2 ) than on the dorsal surface (55.98 ± 1.452 per mm2 ). The stomata were sunken. The size of the stomatal complex (stoma + epicuticular dome) was comparable on the two foliar surfaces. In all, seven fungal species (4 genera) were found to associate with Jojoba seeds and seedlings - Rhizopus stolonifer, Aspergillus niger, A. flavus, A. terreus, A. fumigatus, Fusarium solani and Absidia sp. Absidia sp. only associated with seeds in internalized state.
