Preliminary evaluation of macadamia rootstocks for yield and tree height

Rootstock has profound effects on traits such as yield and tree size in various horticultural industries, however relatively little is known about rootstock effects for macadamia. In this study, 12 cultivars were propagated as open-pollinated seedling and clonal rootstocks, and own-rooted cuttings. The same cultivars were also used as scions, and grafted to a subset of rootstocks, then planted at four trial locations. In this preliminary analysis, rootstock accounted for 19% of the variance in yield compared with 72% for scion, and 23% in height compared with 72% for scion. There was no interaction between rootstock and scion for yield, and only a small effect for height. The interaction between rootstock and propagation method (seedling, clonal, own roots) was not significant for height. A small effect was observed for yield, with the own roots treatment producing significantly lower yield than grafted trees for all rootstock cultivars except 'HAES 849'. 'H2' seedling rootstock produced a cumulative yield to age 10 years of 11.1 kg tree -1 compared to the highest yield of 13.6 kg tree -1 for 'Beaumont' clonal rootstocks. 'H2' seedling rootstock produced 4.8 m trees at age 11 years, compared to the smallest grafted tree which was 'HAES 849' seedling at 4.7 m.

The Experimental Study of Injection and Mixing of the Model Ejector Rocket

专门设计了可用于研究箭基组合循环发动机(RBCC)在起动阶段(Ma=0)所使用的引射火箭性能的实验装置.作为初步试验,研究了不同工况的引射热喷流(一次流)和被引射空气(二次流)之间混合的演变、发展过程,找出不同来流条件下影响引射性能的主要参数,为最终探明引射火箭的最佳工作条件打下基础,同时根据试验结果提出了促进一、二次流混合的可行方案,便于下一步深入研究.

Effects of cell density, light intensity and mixing on Undaria pinnatifida gametophyte activity in a photobioreactor

An on-line controlled 7 1 sterilizable photobioreactor was used for the optimisation of a culture of gametophytes of Undaria pinnatifida. The gametophytes, which had been stored for three years in a culture cabinet at 16 degreesC, could rapidly grow in the photobioreactor under controlled conditions. The rate of increase of dissolved oxygen and pH were used to monitor the photosynthetic activity. Optimal gametophytes density changed varying the light intensity. The optimal cell densities were 3.24 and 3.45 g FW l(-1) when the cultures were exposed to 61.7 and 82.3 muE m(-2) s(-1), respectively. The optimal cell density was higher under a high photon flux density (PFD) than under low PFD. On the other hand, the optimal light intensities were different for different cell density cultures. The light saturation point was higher at high cell density cultures than at low cell density cultures. The optimal rotational speed was 150 rpm for high cell density culture in the photobioreactor. (C) 2003 Elsevier B.V. All rights reserved.

Effect of temperature and mixing conditions on quality and consistency of poly(methyl methacrylate) bone cement

The mixing of poly(methyl methacrylate) (PMMA) bone cement has been studied to develop methods for preparing a consistently high quality cement. A novel droplet test experimental procedure was developed that characterised the wetting characteristics involved in bone cement mixing. Using this technique it was established that increased wetting occurred by mixing bone cement at a lower temperature (-28 degreesC) than normal mixing at room temperature.