No abstract

Recording of bud status at successive phytomers on the tiller axis in perennial ryegrass was shown to provide information similar to that obtained from conventional recording of tiller appearance by monitoring marked tillers. The technique can be extended to monitor the number of roots formed. These observations lead to the establishment of a notation which describes tiller and root appearance, respectively, on the basis of probability or frequency per phytomer. These statistics are analogous to but less ambiguous in their interpretation than site filling statistics currently used to define tiller, and sometimes root, appearance. Potential modelling applications of quantifying sward dynamics at the phytomer level are discussed. In particular, nodal frequency statistics allow development of mass flow equations to describe leaf, tiller, and root production, and seasonal variation in allocation of photosynthate to developing tillers and roots.

Significant differences were found in a wide variety of textural attributes in eight winter squash cultivars (Cucurbita maxima Duchesne) assessed at 4-5 and 9-10 weeks after harvest using both a trained sensory panel and an Instron Universal Testing Machine. The Instron texture profile analysis force-displacement curves were distinctive for each of the eight cultivars tested, with behaviour under deformation forces indicating differences in the structure and composition of the tissue. Starch and logged dry matter contents varied significantly between cultivars, and were strongly correlated with all the sensory textural attributes rated, and with gumminess and hardness (dry matter only) measured by the Instron. Simple linear regressions indicated significant relationships between textural attributes as measured by the sensory panel and the Instron.

No abstract

Spaced poplar (Populus spp.) trees are used widely in New Zealand for soil conservation on erodible pastoral hill country. Their root distribution in this environment, and factors that affect it, are poorly understood. Robust recommendations on effective tree spacing depend on knowledge of root systems. This study determined the effect of tree density, position between trees, and soil depth (0-90 cm) on root number, root diameter distribution, root area ratio (RAR), and cross sectional area per root for young trees on slopes. Data were collected for lateral roots using trenches. Greater than 80% of roots were < 5 mm diameter and root attributes were highest in shallow soil. Trees at 770 stems per hectare (sph) had 3-12 times more roots and 3-9 times greater RAR than those at densities of ≤ 237 sph, representative of most tree-pasture systems. Mean cross sectional area per root was similar across densities. Positions close to trees had twice as many roots (46 vs. 23/m 2 ) and RAR (109 vs. 52 mm 2 /m 2 ) as positions midway between trees. The study provided quantitative understanding of variation in root distribution with tree density and information useful for supporting and strengthening recommendations on densities for effective erosion control.