AUSSAT battery life test program

AUSSAT Pty. Ltd., the Australian National Satellite organization, has contracted with the Hughes Aircraft Company (HAC) for the construction of 3 satellites based on the now familiar HS-376 product line. As part of the AUSSAT contract, HAC is conducting an extensive NiCd battery life test program. The life test program, objectives and test results to date are described. Particular emphasis is given to the evaluation of the FS2117 separator as a future replacement for the Pellon 2505 separator of which only a very limited quantity remains

Management of genetic resources in the nursery system of wild cherry (<i>Prunus avium</i> L.)

Knowledge of genetic and adaptive traits of reproductive materials used in the nursery system of wild cherry, could be an useful instrument to improve ecological and economic sustainability of plantation ecosystems. This work reports results from a research which the objectives were: 1) to study the genetic variation of a <i>Prunus avium</i> L. Population, used for seed harvesting, through its multi-locus genotypes detected by starch gel electrophoresis; 2) to analyze the level of genetic variation within and among different steps in a commercial nursery system (basic population and sub-populations, seedlings aged S₁T₁ and S₁T₂, plantation). Results showed low genetic variation levels of the basic population, similar to a reference system of other 12 wild cherry Italian populations and to other French and Caucasian materials. The genetic distances among Monte Baldo and some closer Lombardy provenances (Area Garda, Bosco Fontana, Valtellina) were smaller than the Venice Region populations (Monti Lessini and Asiago). Number of alleles and percentage of polymorphic loci within the complex of Monte Baldo provenance and multiplication materials were similar, whilst a variable value of Fis was noted. Indeed, along with the nursery system until the plantation, heterozygosis initially (S₁T₁) increased, then decreased proceeding to the plantation. This fluctuation of F_IS values could be determined by seed lots characterized initially by higher levels of variation, due to self-incompatibility. In the following steps, a possible selection pressure can affect randomly the genotypic structure of wild cherry by increasing the homozygosity. There is not among population a well defined geographic characterization, as suggested by genetic distances, therefore homogeneous seed harvest could be established an area larger than geographic and administrative borders. On this way we could have reproductive material with a wide genetic base and environmental adaptability. To increase variability in the progenies, populations characterised by wider cross pollination rates should be selected, harvest seed by all plants of population, reduce selection on seedlings during nursery growth

Acorn storage in airtight polyethylene bag maintains high germination in recalcitrant holm oak (Quercus ilex L.)

Storage of recalcitrant seeds of wild species is one of thorniest problems not yet resolved in forestry science. In particular, the acorns show a rapid deterioration and a sudden decrease in germination within the first year of storage. The aim of this work was to study phenomena related to the loss of germination of a Mediterranean recalcitrant forest species, the holm oak (Quercus ilex L.), possibly suggesting some treatments able to improve the storage of the oaks. Two different provenances were taken in order to check if the geographical area can affect the conservation of the seed lots. Three different treatments were applied to determine the best conservation method suited to increase seed storage: 1) standard conditions in plastic can with lid at +3\ub0C with 60% RH, 2) stratification in sand and 3) airtight storage in thin polyethylene bags. During the crop year 2008-2009, every two months samples from each storage treatment were tested for moisture content and germination, two of the main characteristics of seed quality. Furthermore, leakage conductivity of acorns was measured as marker of seed membrane integrity. Preliminary data regarding some physiological markers involved in the decrease of the seed quality are presented, as possible explanation of the phenomenon; in particular the role played by oxidative stress during the storage process is discussed

Stato energetico e capacit\ue0 antiossidante in semi recalcitranti di leccio (Quercus ilex L.) conservati in sacchetti di polietilene.

Il leccio (Quercus ilex L.) costituisce una tipica specie recalcitrante dell\u2019area mediterranea che si caratterizza per una debole dormienza e per una spiccata sensibilit\ue0 alla disidratazione nei semi. Per descrivere e comprendere meglio i meccanismi fisiologici e biochimici che sottostanno a queste peculiarit\ue0, sono stati misurati nel corso della conservazione alcuni parametri tecnologici e biologici. I semi, mantenuti in condizioni di elevata umidit\ue0 e bassa temperatura, sono stati conservati secondo le usuali metodiche in bidoni riempiti con torba umida per un intero anno. Tale modalit\ue0 \ue8 stata confrontata con una soluzione che prevedeva l\u2019uso di sacchetti in polietilene. L\u2019accorgimento adottato ha consentito di mantenere un livello accettabile di germinazione per un periodo superiore di circa 3 mesi rispetto al controllo e di rallentare il deterioramento del seme grazie a un miglior controllo dei danni provocati dal metabolismo ossidativo. La barriera costituita dal film plastico ha infatti limitato gli scambi gassosi, prevenendo le alterazioni dovute a una respirazione troppo elevata e alla liberazione di H2O2. L\u2019ambiente ipossico ha mantenuto un miglior equilibrio ossidoriduttivo, preservando il contenuto di glutatione ridotto e di ATP. La conservazione nei sacchetti ha inoltre favorito l\u2019accumulo di etilene nell\u2019atmosfera di stoccaggio e ha abbassato le attivit\ue0 metaboliche dei semi, nonostante il loro intrinseco stato di debole dormienza. Un\u2019appropriata modulazione di questi fattori biologici potrebbe consentire il prolungamento del periodo di conservazione in semi recalcitranti