NUTRITION AND GROWTH OF JOJOBA, SIMMONDSIA CHINENSIS (LINK) SCHNEIDER, DURING VEGETATIVE PROPAGATION.

摘要

Jojoba cuttings were fertilized during rooting under mist. Rooted cuttings were evaluated for growth and element concentrations. Also investigated were: CO₂ exchange during rooting; media, light and nutrition effects on nursery growth; and nutrition effects on field establishment. Fertilizer formulations used were: Peter's soluble, Osmocote, IBDU, and SCU. Rooting was depressed at 5.46 kg m⁻³ IBDU. High rates of either Osmocote or Peter's increased root weights over controls in spring. Osmocote-treated cuttings were greater than controls in nodes, fresh weight and succulence. Initial leaf concentrations of N, P and K were lower in spring than in summer and greater at lining-out for fertilized cuttings. Leaf N and K were positively related to root and shoot growth in spring and to shoot growth in summer. Leaf Zn was positively related to shoot and root growth in spring. Treatment differences in leaf element concentrations vanished after 3 months in the nursery. Differences in growth persisted for up to six months. Fertilization during rooting did not effect CO₂ exchange processes. Apparent photosynthesis (AP) declined until rooting and then rose with root growth as did root respiration. Dark respiration (Rd) dropped to a stable rate and did not increase as fast as AP upon rooting. During rooting AP, Rd and leaf succulence were well correlated. New nodes for liners grown in media with air porosities of 18.5 and 27.6 percent were equivalent. Nodes, fresh and dry weight, leaf area and specific leaf weight were greater for sun-grown than for 50 percent shade-grown liners. Shade-grown liners were more succulent. Plants grown in Osmocote amended media produced more nodes, leaves and flowers than did controls. Plants unfertilized during rooting grew fastest when grown with Osmocote in the nursery media, but were smaller at 3 months than plants fertilized during roots. Field survival after five months was not significantly affected by nutritional treatments. Growth after transplanting was significantly greater for plants fertilized in the nursery. Rooting stage fertilization is beneficial if plants are not held too long in the nursery. Nursery stage nutrition is very important for good stand establishment and growth of jojoba transplants.