A comparative study of young ‘Thompson Seedless’ grapevines under drip and furrow irrigation. I. Root and soil water distributions

Soilwater distribution, soilwater extraction, and root distributions were determined for young grapevines (Vitis vinifera L. cultivar ‘Thompson Seedless’) grown under drip and furrow irrigation near Fresno, CA, USA. Soilwater content and extraction was determined to a depth of 0.9 m by neutron scattering from an array of nine access tubes installed throughout one-quarter of the soil volume available to each vine. Root distribution was determined from root intersections with vertical planes established parallel and perpendicular to the vine row. Drip irrigation was applied daily according to estimated evapotranspiration, and furrow irrigation was managed according to 50% depletion of the plant available soil water. Drip and furrow irrigated vines showed similar water status and shoot growth patterns. There was a confined soil wetted zone beneath the emitter discharge that largely coincided with a confined and shallow root system of drip irrigated vines. In contrast, furrow irrigated vines had a deeper and more widespread root system. Differences between water applied and soilwater content 3 days after irrigation suggested large water losses by evaporation during that period for furrow irrigated vines. Consumptive use of furrow irrigated vines was 12.5% greater than drip irrigated vines, but similar irrigation efficiencies were obtained for both irrigation systems when soilwater status was carefully monitored. Water applications for both irrigation systems were less than 50% of the longterm mean for irrigation deliveries to farms in the area. Thus, the results indicate that a significant potential for water savings exists in the San Joaquin Valley by means of irrigation management. It is concluded that relatively high and similar irrigation efficiency can be obtained with both drip and furrow irrigation of young grapevines in arid and semiarid regions when careful management is used.     

Radio Tracer Studies on P Use Efficiency in a Rice Based Cropping System

Tracer studies using ³²P labelled superphosphate and rock phosphate were conducted in microplots in a field experiment on rice-rice-greengram cropping system. The trial revealed that in all the rice crops studied, P uptake and P use efficiency were higher in superphosphate treated plots than in rock phosphate applied ones. P uptake was improved with organic manuring through application of green manure or crop residues like long rice stubbles. While superphosphate performed well either with or without organic manuring, rock phosphate performed fairly well only with organic manuring. Fairly good P use efficiency could be obtained in the system when green manuring and rock phosphate application in the first crop was followed by superphosphate and long stubble incorporation in the second crop. Apparent recovery values also showed nearly the same results. But tracer studies were found to be definitely superior in the evaluation of fertilizers.     

Definition of 15 equine leucocyte antigens

Fifteen equine leucocyte antigens were defined by absorption and titration analysis of alloantisera obtained by natural sensitisation through pregnancy and by planned experimental immunisation. Definitive sera were tested on the cells of 90 unrelated horses and members of eight equine families. The family data suggested that 13 specificities were coded by a single locus (first locus) and one specificity (Eq 14) was coded by a second linked locus. The remaining specificity (Eq 7) was controlled by a third locus unlinked to the first or second loci. Tests on the cells of unrelated horses showed that two first locus specificities (Eq 16 and Eq 17) had a supertypic relationship to other first locus antigens. No individual was found to possess more than two first locus antigens, excluding the supertypic specificities.     

Effect of low-dose butorphanol on halothane minimum alveolar concentration in ponies

Minimum alveolar concentration (MAC) for halothane was measured before and after administration of intravenous butorphanol (0.022 and 0.044 mg/kg in bodyweight in nine yearling Shetland ponies. Arterial blood pressure, heart rate, respiratory rate, expired CO2 and rectal temperature was also measured. Even though mean MAC values decreased 10 and 9 per cent after the low and high doses respectively, they were not statistically different from those measured prior to butorphanol. Halothane MAC values increased after butorphanol in two ponies, both animals increasing locomotor activity and demonstrating apparent central nervous system stimulation. No significant differences were seen in any variable measured after butorphanol administration.     

Estimating the mass of asteroid 253 mathilde from tracking data during the NEAR flyby

The terminal navigation of the Near Earth Asteroid Rendezvous (NEAR) spacecraft during its close flyby of asteroid 253 Mathilde involved coordinated efforts to determine the heliocentric orbits of the spacecraft and Mathilde and then to determine the relative trajectory of the spacecraft with respect to Mathilde. The gravitational perturbation of Mathilde on the passing spacecraft was apparent in the spacecraft tracking data. As a result of the accurate targeting achieved, these data could be used to determine Mathilde's mass as 1.033 (+/- 0.044) x 10(20) grams. Coupled with a volume estimate provided by the NEAR imaging team, this mass suggests a low bulk density for Mathilde of 1.3 grams per cubic centimeter.     

Comparisons of cultivar performance on different nutrient media in a routine method for potato micropropagation

Summary The in vitro culture of potato cultivars (Désirée, Estima, Foxton, Pentaland Squire, Record) initiated from tuber sprout buds has been studied with the requirements of a routine method of micropropagation in mind. Comparisons of the growth of the cultivars on media based on Murashige and Skoog (MS) and on Knop showed that although cultivars differed in their propensity to grow through several generations their performance on MS medium was in general superior. Sprout tips grew slower than buds from lower nodes in the first culture generation but no significant differences in growth were seen in later generations. Thus, where limited numbers of buds from lower nodes are available, sprout tips can be used to initiate cultures.

---

Zusammenfassung Die aus Knospen von Knollenkeimen hervorgegangene in vitro Kultur der Kartoffelsorten Désirée, Estima, Foxton, Pentland Squire und Record wurde untersucht im Hinblick auf die Erfordernisse einer Routinemethode für eine Mikrovermehrung. Die N?hrmedien wurden wie folgt bezeichnet: M1: siehe Tab. 1; M2: wie M1, ohne Vitamine; K1: siehe Tab. 1; K2: wie K1, ohne Vitamine. Einige Sorten wuchsen schnell (Désirée, Estima), andere dagegen nur langsam (Record, Foxton) (Tab. 2). Auf dem Medium nach Murashige und Skoog (MS) was das Wachstum allgemein besser als auf dem Medium nach Knop. Einige Sorten (Désirée, Estima) wuchsen zun?chst in gleicher Weise auf beiden N?hrmedien w?hrend andere (Pentland Squire) auf MS-Medium auff?llig besser wuchsen. Unterschiede zwischen den Sorten wurden besonders deutlich, wenn die Kultur über mehrere Generationen hinweg durchgeführt wurde (Abb. 1). Désirée, Foxton und Estima zeigten w?hrend 3 Generationen einen verminderten Wuchs auf Knop's Medium, einen guten aber auf MS-Medium, w?hrmedien in gleicher Weise wuchs. Die Zugabe von Vitaminen zu den N?hrmedien beeinflusste nicht überall das Wachstum, aber in einigen F?llen zeigten einzelne Sorten eine Vorliebe für das Vorhandensein oder für das Fehlen von Vitaminen (Tab. 2). Abschnitte von Keimspitzen auf MS-Medium wuchsen zun?chst langsamer als solche aus den unteren Keimbereichen (Tab. 3), aber die Wachstumsunterschiede verschwanden in den Kulturen nach drei Generationen, so dass bei der Verwendung von Keimspitzen die Vermehrungsrate bei denjenigen Sorten erh?ht werden k?nnte, die kurze oder stark verzweigte Keime aufweisen.

---

Résumé La culture in vitro de plusieurs variétés de pommes de terre (Désirée, Estima, Foxton, Pentland Squire et Record), à partir des bourgeons issus des germes de tubercule a été testée selon les recommandations d'une méthode de routine pour la micropropagation. Quatre milieux nutritifs ont été utilisés: M1=voir tabl. 1; M2=comme M1 mais sans vitamines; K1=voir tabl. 1; K2=comme K1 mais sans vitamines. Certaines variétés (Désirée, Estima) ont poussé rapidement, alors que d'autres (Record, Foxton) ont eu une croissance lente (tabl. 2). Le milieu de Murashige et Skoog (MS) a donné une croissance générale supérieure à celle de Knop. Certaines variétés (Désirée, Estima) ont eu au départ un taux de croissance similaire sur les deux types de milieu, tandis que pour d'autres (Pentland Squire) il f?t nettement plus important sur milieu MS. Les différences entre variétés sont apparues plus nettement après prolongement de la culture sur plusieurs générations (fig. 1). Désirée, Foxton et Estima ont vu leur croissance diminuer au cours de trois générations sur Knop mais non sur milieu MS, tandis que Record eut un niveau de croissance faible mais identique sur les différents milieux. L'apport de vitamines dans le milieu n'a produit aucun effet général sur la croissance, mais dans quelques cas, on notait une certaine préférence pour la présence ou l'absence des vitamines (tabl. 2). Les extrémités de germes cultivées sur milieu MS ont eu une croissance initiale plus faible que les entre-noeuds inférieurs (tabl. 3) mais les différences disparaissent après trois générations de culture, de sorte que les extrémités de germes peuvent augmenter les taux de multiplication pour les variétés à germes courts ou à forte ramification.

     

Peroxidase-antiperoxidase labeling of azospirillum brasilense in field-grown pearl millet

Bacterial cells of Azospirillum brasilense (Tarrand) from their natural habitat were labeled with peroxidase-antiperoxidase (PAP), identified, and observed using the transmission electron microscope. Pure cultures of A. brasilense, axenically inoculated pearl millet root samples, and field-grown inoculated pearl millet root samples were embedded in Luffs araldite. Thin sections were treated using the immunological PAP method. Identification was possible because of the heavy outlining of the cells with a dense deposit of osmium.Pleomorphic forms of A. brasilense were observed in axenic pearl millet root cultures. Encapsulated forms were larger than vibrioid forms, and both types reacted with antiserum against the bacterial strain.     

Defining landscape-level forest types: application of latent Dirichlet allocation to species distribution models

Landscape Ecology - Forest type (FT) classification provides useful information to ecologists and forest managers by representing similar sites based on species dominance. Various methods have been...