Digestive Tract Of Birds Research Articles

Virulence genes identification in Salmonella enterica isolates from humans, crocodiles, and poultry farms from two regions in Colombia.

Salmonella spp. is frequently found in the digestive tract of birds and reptiles and transmitted to humans through food. Salmonellosis is a public health problem because of pathogenicity variability in strains for virulence factors. This study aimed to identify the virulence genes in Salmonella isolates from humans, crocodiles, broiler cloacas, and broiler carcasses from two departments of Colombia. This study was conducted on 31 Salmonella enterica strains from humans with gastroenteritis (seven), crocodiles (seven), broiler cloacas (six), and broiler carcasses (12) from Tolima and Santander departments of Colombia, belonging to 21 serotypes. All samples were tested for Salmonella spp. using culture method on selective and non-selective mediums. Extraction of genomic DNA was performed from fresh colonies, DNA quality was verified by spectrophotometry and confirmed by amplification of InvA gene using conventional polymerase chain reaction (PCR). bapA, fimA, icmF, IroB, marT, mgtC, nlpI, oafA, pagN, siiD, spvC, spvR, spvB, Stn, and vexA genes were amplified by PCR. The most prevalent gene was bapA (100%), followed by marT (96.77%), mgtC (93.55%), and fimA (83.87%). Likewise, IroB (70.97%), Stn (67.74%), spvR (61.29%), pagN (54.84%), icmF (54.8%), and SiiD (45.16%) were positive for more than 50% of the strains. Furthermore, none of the isolates tested positive for the vexA gene. Salmonella isolates presented 26 virulence profiles. This study reported 14 virulence genes in Salmonella spp. isolates from humans with gastroenteritis, crocodiles, and broiler cloacas and carcasses. The distribution of virulence genes differed among sources. This study could help in decision-making by health and sanitary authorities.

DEHP triggers a damage severity grade increase in the jejunum in quail (Coturnix japonica) by disturbing nuclear xenobiotic receptors and the Nrf2-mediated defense response

As a plasticizer, di-2-ethylhexyl phthalate (DEHP) has been listed as a potential endocrine disruptor by The World Health Organization. The toxicity of DEHP has been widely studied, but its toxicity on the digestive tract of birds has not been clarified. Female quail were treated by gavage with DEHP (250, 500, 750 mg/kg), with the blank and vehicle control groups reserved. The result showed that DEHP raised the damage severity grade, and decreased the ratio of villus length to crypt depth. The content and activity of cytochrome P450 system (CYP450s) were increased by DEHP. DEHP interfered with the transcription of nuclear xenobiotic receptors (NXRs), CYP isoforms, and the nuclear factor-E2-related factor 2 (Nrf2) signaling pathway. This study revealed DEHP could cause the imbalance in CYP450s mediated by NXRs, and then promote Nrf2 mediated antioxidant defense. This study provided new evidence about the mechanisms of DEHP-induced toxic effects on digestive tract.

Use of fly larvae Hermetia illucens in poultry feeding: A review paper

The paper presents the review of scientific publications of world literature on the use of the larvae of black soldier fly ( Hermetia illucens) when feeding poultry. Nowadays, the issue of replacing traditional sources of protein when feeding poultry is very urgent, especially in connection with the global food crisis. Insects are the natural food of most birds; thus, the use of fly larvae for feed production has a biological basis. The research results presented in published works show that there are no negative effects on bird health and meat quality when feeding poultry, quail and other birds. In some cases, the experimental groups of birds gained weight slightly more slowly than the control group. Other reports indicate that birds grew at the same rate as normal birds. The quantity and quality of eggs did not differ significantly, but dietary changes affected the colour of yolks and eggshell. The effect of the addition of live larvae to the diet of young turkeys on the weight characteristics of was studied. Replacing 10% of the daily amount of feed with live Hermetia illucens larvae in the diet of turkeys showed that the daily feed intake and body weight gain of the experimental birds were significantly higher compared to the control groups, which led to a significantly higher body weight of chicks at the age of five weeks (2.19 kg vs. 2.015 kg, respectively) and a significantly lower feed conversion rate. Most researchers agree that replacing protein in poultry feed with insect flour should be partial, in the 15–30% range. Feeding with larvae that have undergone processing – grinding, chitin removing, heat treatment – is more preferable than using whole larvae, since the chitinous membrane makes larvae difficult to be digested in the digestive tract of birds.

Seed dispersal in Neuwiedia singapureana: novel evidence for avian endozoochory in the earliest diverging clade in Orchidaceae

BackgroundSeed dispersal allows plants to colonize new habitats that has an significant influence on plant distribution and population dynamics. Orchids produce numerous tiny seeds without endosperm, which are considered to be mainly wind-dispersed. Here, we report avian seed dispersal for an early diverging orchid species, Neuwiedia singapureana, which produces fleshy fruits with hard seed coats in the understory of tropical forests.ResultsNeuwiedia singapureana produced fleshy fruits that turned red in autumn, and birds were confirmed to be the primary seed dispersers. As compared to its sister species, N. veratrifolia with dehiscent capsular fruits, embryos of N. singapureana were larger and enclosed by thickened and lignified seed coats. After passing through the digestive tracts of birds, the seeds still stayed alive, and the walls of seed coat contained several cracks. The germination percentage increased significantly for digested seeds as compared with seeds from intact fruits.ConclusionThe thickened and lignified seed coat may protect seeds as they passed through the digestive tracts of birds. Taken together with a recent report of insect-mediated seed dispersal system in the subfamily Apostasioideae, the animal-mediated seed dispersal may be an adaptive mechanism promoting the success of colonization in dark understory habitats.

Analysis of Glycosyl-Enzyme Intermediate Formation in the Catalytic Mechanism of Influenza Virus Neuraminidase Using Molecular Modeling.

Using classical molecular dynamics, constant-pH molecular dynamics simulation, metadynamics, and combined quantum mechanical and molecular mechanical approach, we identified an alternative pathway of glycosyl-enzyme intermediate formation during oligosaccharide substrate conversion by the influenza H5N1 neuraminidase. The Asp151 residue located in the enzyme mobile loop plays a key role in catalysis within a wide pH range due to the formation of a network of interactions with water molecules. Considering that propagation of influenza virus takes place in the digestive tract of birds at low pH values and in the human respiratory tract at pH values close to neutral, the existence of alternative reaction pathways functioning at different medium pH can explain the dual tropism of the virus and circulation of H5N1 viral strains capable of transmission from birds to humans.

Coconut meal as a feed ingredient and source of prebiotic for poultry

The low quality protein of coconut meal, coupled with high fibre content, leads to limited use of this agricultural by-product in the poultry diet. Attempts to maximize the amount of coconut meal included in the broiler feed have been made through amino acids supplementation, enzyme addition and pelleting coconut meal. Among these feed technologies and manipulation, pelleting coconut meal appears to be more powerful in promoting the growth of broiler chickens. The reasons for the improvement of broiler growth due to pelleting coconut meal have not been established yet. The mechanisms of improved growth of birds might be through increased feed intake, less energy spent and increased bulk density. Coconut meal contains a high concentration of mannose – based polysaccharides or mannan. This substance has long been believed to have prebiotic properties due to its capability to bind certain species of pathogenic bacteria in the digestive tract of birds. Voluminous reports of the positive effects of mannose-based polysaccharides from yeast have been published. Mannose –based polysaccharides from legumes, on the other hand, have been reported to have anti-nutrient property. Surprisingly, mannose-based polysaccharides from coconut behave like yeast mannan. A number of current studies indicated that mannose based polysaccharides improved body weight gain and feed digestibility. The growth of birds was negatively impacted when the birds were challenged against pathogenic bacteria of E. coli. Wet droppings and diarrhea incidences were not found in E. coli-challenged birds when the diets were supplemented with coconut mannan. In conclusions, coconut meal can be used as a feed ingredient for poultry unless the coconut meal was pelleted or enzymatically treated. Mannose-based polysaccharide from coconut was effective to promote growth and acted as prebiotic.

Occurrence of Tetratrichomonas gallinarum (Trichomonadida: Trichomonadidae) in chicken feces from Lorestan Province, Western Iran.

Species of Tetratrichomonas gallinarum and Trichomonas gallinae, are found in the digestive tract of birds. To investigate trichomonads of a lower intestinal tract of native chickens, we examined 72 feces samples from the different life stages of fowl species in Khorramabad County, Lorestan Province, Western Iran. Using microscopical examination, out of 72 collected samples, 26 (31.6%) bird feces samples were found infected with a trichomonad similar to T. gallinarum. A 527-bp fragment of 18S rRNA gene of T. gallinarum was amplified by PCR. The 18S constructed phylogeny indicates two different clades within T. gallinarum, suggesting that commensal T. gallinarum-like of the bird hosts may be the reason for the genetic divergence in T. gallinarum species complex.

Significance of Streptococcus gallolyticus subsp. gallolyticus Association With Colorectal Cancer.

Streptococcus gallolyticus subsp. gallolyticus Sgg (formerly known as S. bovis type I) is the main causative agent of septicemia and infective endocarditis (IE) in elderly and immunocompromised persons. It belongs to the few opportunistic bacteria, which have been strongly associated to colorectal cancer (CRC). A literature survey covering a period of 40 years (1970–2010) revealed that 65% of patients diagnosed with an invasive Sgg infection had a concomitant colorectal neoplasia. Sgg is associated mainly with early adenomas and may thus constitute an early marker for CRC screening. Sgg has been described as a normal inhabitant of the rumen of herbivores and in the digestive tract of birds. It is more rarely detected in human intestinal tract (2.5–15%). Recent molecular analyses indicate possible zoonotic transmission of Sgg. Thanks to the development of a genetic toolbox and to comparative genomics, a number of factors that are important for Sgg pathogenicity have been identified. This review will highlight the role of Sgg pili in host colonization and how their phase-variable expression contributes to mitigate the host immune responses and finally their use as serological diagnostic tool. We will then present experimental data addressing the core question whether Sgg is a cause or consequence of CRC. We will discuss a few recent studies examining the etiological versus non-etiological participation of Sgg in colorectal cancer with the underlying mechanisms.

Effect of l-tryptophan and its metabolites on food passage from the crop in chicks

l-tryptophan (l-Trp), an essential amino acid, is well known as a precursor of 5-hydroxytryptamine (5-HT) and melatonin. In mammals, l-Trp itself has been reported to suppress gastric emptying in mammals. In addition, 5-HT and melatonin are found in the gastrointestinal tract and affect food passage from the digestive tract in mammals. While the function of these factors in mammals is documented, there is little knowledge on their function in the digestive tract of birds. Therefore, the purpose of the present study was to determine if l-Trp and its metabolites affect the crop emptying rate in chicks (Gallus gallus). We also investigated the effects of kynurenic acid (KYNA) and quinolinic acid (QA), which are metabolites of the kynurenine pathway for l-Trp. Oral administration of l-Trp significantly reduced the crop emptying rate in chicks. Among the metabolites, intraperitoneal injection of 5-HT and melatonin significantly reduced the crop emptying rate, whereas KYNA and QA had no effect. The present study suggests that l-Trp, 5-HT, and melatonin inhibit the movement of food in the digestive tract and thereby affect the utilization of nutrients in the diet of chicks.

Occurrence of Enterococcus spp. in poultry in Poland based on 2014–2015 data

Bacteria of the genus Enterococcus are mainly commensals building natural microflora in the digestive tract of birds and mammals. They belong to the potentially pathogenic microorganisms. Among poultry, infections caused by enterococci were reported in chickens, turkeys, ducks and ostriches. The aim of this study was to evaluate the occurrence of enterococci in poultry in Poland, including identification of enterococcus species composition and determination of the age of birds. The analysis was based on data obtained from 2014 – 2015 from Division of Avian Diseases at Warsaw University of Life Sciences-SGGW and four veterinary laboratories in Poland: Lab – Vet, Tarnowo Podgórne; SLW Biolab, Ostróda; Vetdiagnostica, Solec Kujawski; Vet – Lab Brudzew. Seven enterococcal species were isolated from broiler chickens (CB), commercial layers (CL), and broiler breeder flocks (BB), nine from all poultry types (chickens, turkey, ducks and geese). The most often isolated enterococci from CB were E. faecalis (57%) > E. cecorum (7%) > E. faecium (5.2%) > E. hirae (3.6%) > E. gallinarum (2.5%) > E. casseliflavus (0.7%) > E. durans (0.2%). Seven Enterococcus species were isolated from sources associated with poultry, most often E. faecalis > E. faecium > E. cecorum > E. hirae. The differences in the occurrence of particular enterococcal species were observed between CB, BB and CL. The mean age at the time of isolation of E. cecorum was approx.: 3.6 weeks in CB, 27.5 weeks in BB, 33.3 weeks in CL, 12.9 weeks in turkeys, 3.6 weeks in ducks, 39.5 weeks in geese. E. faecalis and E. faecium dominated in samples obtained from hatching eggs, dead-in-shell embryos and from samples related to poultry environment. In conclusion, this study indicates the high prevalence of bacteria of the Enterococcus genus in poultry. The present findings demonstrate the differences in Enterococcus species between poultry groups, including with regard to age. In total 10 enterococcal species (E. faecalis, E. cecorum, E. hirae, E. faecium, E. gallinarum, E. casseliflavus, E. durans, E. avium E. thailandicus, E. aquimarinus) were detected in poultry, poultry environmental samples, hatching eggs and dead-in-shell embryos. Enterococcus faecalis and E. cecorum were found in all above-mentioned sources.

Dispersión Legítima De Semillas Por Aves En El Bosque Y Matorral Serrano De La Provincia De Córdoba

Birds play a fundamental role in many ecosystems because through endozoochory they can disperse lots of fruits and herefore its seeds. In the southern hemisphere, temperate forests and hills scrub of Córdoba-Argentina are characterized by great floristic diversity and an important richness of birds. However, only few studies focusing on the role of birds as dispersers of fruits and seeds have been conducted in this ecosystem. The aims of this study was to investigate if birds are dispersing fruits or seeds in the forest and hills scrub; analyse if fruits or seeds dispersion is scattered along seasons; and to assess whether seeds suffer physical damage when passing through the digestive tract of birds. During July, August, September and December 2012, fruits and seeds from birds pellets were collected while walking through two linear transects (length and width) of 1,450 x 20 and 1,200 x 5 m, respectively. Results showed that birds dispersed seeds during all seasons although the largest proportion was observed during autumn and winter when more than 70% of birds pellets contained seeds. The highest proportion of damaged seeds occurred in September (11%), but overall proportion of seeds that had physical damage was very low. Finally, our results revealed that birds have an important role in seeds dispersion on the forest and hills scrub ecosystem, and most of these dispersed seeds were exotic.

Facilitated Leaching of Additive-Derived PBDEs from Plastic by Seabirds’ Stomach Oil and Accumulation in Tissues

Our previous study suggested the transfer of polybrominated diphenyl ether (PBDE) flame retardants from ingested plastics to seabirds' tissues. To understand how the PBDEs are transferred, we studied leaching from plastics into digestive fluids. We hypothesized that stomach oil, which is present in the digestive tract of birds in the order Procellariiformes, acts as an organic solvent, facilitating the leaching of hydrophobic chemicals. Pieces of plastic compounded with deca-BDE were soaked in several leaching solutions. Trace amounts were leached into distilled water, seawater, and acidic pepsin solution. In contrast, over 20 times as much material was leached into stomach oil, and over 50 times as much into fish oil (a major component of stomach oil). Analysis of abdominal adipose, liver tissue, and ingested plastics from 18 wild seabirds collected from the North Pacific Ocean showed the occurrence of deca-BDE or hexa-BDEs in both the tissues and the ingested plastics in three of the birds, suggesting transfer from the plastic to the tissues. In birds with BDE209 in their tissues, the dominance of BDE207 over other nona-BDE isomers suggested biological debromination at the meta position. Model calculation of PBDE exposure to birds based on the results of the leaching experiments combined with field observations suggested the dominance of plastic-mediated internal exposure to BDE209 over exposure via prey.

Impact and Manipulation of Gut Microflora in Poultry: A Review

Gut microbial population of chicken mainly comprises of gram positive bacteria, most of which are facultative anaerobes from crop to terminal ileum while caeca additionally contain strict anaerobes. In chickens, the main site of bacterial activity are the crop and the caeca and to a lesser extent, the small intestines. Bacterial fermentation of most non-digestible carbohydrates occurs in the crop and caeca resulting in the production of Short-Chain Fatty Acids (SCFAs) which may provide extra energy to the bird. SCFAs can accelerate gut epithelial cell proliferation thereby increasing intestinal tissue weight resulting in changes of mucosal morphology. Certain beneficial bacteria create a microenvironment hostile to other bacterial species by producing antimicrobial metabolites, a process known as competitive exclusion. The digestive tract of birds also contains pathogenic such as Salmonella, Escherichia coli, Clostridium perfringens, etc. which produce harmful substances like endotoxins. These endotoxins cause fever and the release of endogenous pyrogens which act on thermoregulation centres in the hypothalamus. The development of gut and the competitiveness of beneficial and harmful bacteria can be altered by dietary manipulation (enzymes, prebiotics, probiotics, mannan oligosaccharides and symbiotics) which can alter not only gut dynamics but also many physiologic processes due to the end products metabilosed by symbiotic gut flora.

Biochemical Impact of the Host Adaptation-associated PB2 E627K Mutation on the Temperature-dependent RNA Synthesis Kinetics of Influenza A Virus Polymerase Complex

Most avian influenza A viruses, which preferentially replicate at the high temperatures found in the digestive tract of birds, have a glutamic acid at residue 627 of the viral RNA polymerase PB2 subunit (Glu-627), whereas the human viruses, which optimally replicate at the low temperatures observed in the human respiratory tract, have a lysine (Lys-627). The mechanism of action for this mutation is still not understood, although interaction with host factors has been proposed to play a major role. In this study, we explored an alternative, yet related, hypothesis that this PB2 mutation may alter the temperature-dependent enzymatic polymerase activity of the viral polymerase. First, the avian polymerase protein, which was purified from baculovirus expression system, indeed remained significantly active at higher temperatures (i.e. 37 and 42 °C), whereas the human E627K mutant drastically lost activity at these high temperatures. Second, our steady-state kinetics data revealed that the human E627K mutant polymerase is catalytically more active than the avian Glu-627 polymerase at 34 °C. Importantly, the E627K mutation elevates apparent K(cat) at low temperatures with little effect on K(m), suggesting that the E627K mutation alters the biochemical steps involved in enzyme catalysis rather than the interaction with the incoming NTP. Third, this temperature-dependent kinetic impact of the human E627K mutation was also observed with different RNA templates, with different primers and also in the presence of nucleoprotein. In conclusion, our study suggests that the amino acid sequence variations at residue 627 of PB2 subunit can directly alter the enzyme kinetics of influenza polymerase.

Heterodera glycines: procedures for official control

<i>Heterodera glycines:</i> procedures for official control

Ecology of fruit‐colour polymorphism in Myrtus communis and differential effects of birds and mammals on seed germination and seedling growth

Summary The fruit‐colour polymorphism of Myrtus communis, a common Mediterranean shrub, is examined. We investigate whether frugivores affect the maintenance of the polymorphism, whether morphs differ in germination or seedling growth, and whether passage through frugivores’ gut affects seed behaviour and seedling growth. Blue berries are very similar in morphological traits and nutrient composition to the rarer white morph. Rates of fruit removal by birds, the main dispersers of this species, did not differ between morphs, suggesting that a colour preference is not involved in maintenance of the polymorphism. Seeds of the two morphs showed the same germinability (final percentage germination) as well as similar rates of germination under controlled conditions (in growth chamber and greenhouse). Outdoors, seeds from blue berries tended to germinate slightly faster (which might give them an early advantage) but differences between morphs disappeared after several weeks of growth. The germination of myrtle seeds is differently affected by passage through the digestive tract of birds, which appeared to significantly increase germinability, and of the carnivorous pine marten, Martes martes, which did not. The different seed retention time in the gut or the chemical composition of the food ingested along with the seeds may be responsible for such differences. The detection of a positive effect of bird ingestion in outdoor conditions, but not in the growth chamber or in the greenhouse, demonstrates the importance of performing germination tests in the natural habitat. Seed size, irrespective of morph, affects the response to passage through the bird gut. Large seeds, which are more rapidly ejected, and are thus less abraded, germinated at a similar speed to non‐ingested controls. Variation in seed size within a single species should thus be considered in future studies.

Spores of Frankia strain HFPCcl3 nodulate Casuarina equisetifolia after passage through the digestive tracts of captive parakeets (Melopsittacus undulatus)

Spores of Frankia strain HFPCcl3 nodulated Casuarina equisetifolia after passage through the digestive tracts of captive parakeets (Melopsittacus undulatus). Parakeets excreted infectious fecal material from 6 to 72 h after ingesting food inoculated with Frankia spores. Air desiccation of spore-containing fecal material reduced its infectious capacity by approximately 90%. Hyphal filaments of this strain lost most of their infectious capacity after passage through parakeet digestive tracts. These results indicate that it is possible for spores of Frankia to survive passage through the digestive tracts of birds, thereby predisposing them to avian dispersal. Key words: actinorhizal plants, Casuarina, Frankia, nodulation, parakeets, spores.

That's Great!

Last week I read an article about the digestive tracts of birds. I was fascinated to learn that the house wren's intestine grows longer in winter to accommodate the increased food supply needed to maintain body temperature at low environmental temperatures (Karasov 1993). Not only does the intestine grow over 20% longer, it also becomes more efficient at absorbing nutrients. Several other species, including the rock ptarmigan and the spruce grouse, also grow longer guts at times when they eat more food. Other bird species have different digestive adaptations to seasonal changes in food supplies. The robin is not good at absorbing sugars from the intestine, but during the fall and winter when insects are scarce, this bird relies more heavily on fruits. With a change from a high-insect to a highfruit diet, the speed at which food moves through the robin's digestive tract increases. Since absorption is inefficient, the only way the bird can obtain enough nutrients is to move a lot of food through the digestive tract as rapidly as possible. While I knew that the digestive tracts of humans and other animals respond to changes in diet, I didn't know that the response could be as striking as a 20% increase in intestinal length or a 100% increase in the transport rate. Reading articles that describe fascinating adaptations such as these is one of the joys of being a biologist. After finishing an article like this, I just sit back and say, That's great! Because the living world is so rich, there are many articles that elicit this response, and I'd like to discuss a few of them in this column.

An Experiment on Germination of Ligustrum and Paederia Seesd collected from Bird Droppings

An experiment on germination of the seeds collected from bird droppings was carried out from February 3 to March 25, 1978. The species of the seeds were Ligustrum japonicum and Paederia scandens, both of which are widely distributed and are abundant in urbanized areas in Tokyo. The seeds of these plants are found quite commonly in the droppings of fruit-eating birds, such as Brown-eared Bulbuls, Hypsipetes amaurotis. The material of the experiment consisted of the following 3 groups; (A) seeds obtained from bird droppings, (B) seeds with the pericarp removed artificially, and (C) seeds with the pericarp intact.The results of the experiment are given in Figs. 1-2. The seeds of A group, which passed through a bird's digestive tract, showed a tendency to germinate earlier and have a higher germination rate than the others (B and C groups). In the case of L. japonicum seeds, A and B groups showed 100% rate of germination, This suggests that a germination-inhibiting material included in the pericarp was removed in the course of digestion in the digestive tract of birds. But in the case of P. scandens seeds, B group showed a lower germination rate than A group. Consequently not only the removal of the germination-inhibiting material but some other factors, such as physical impact on the seeds by the bird bill, may also be involved.Recently the population of Brown-eared Bulbul is increasing in urbanized areas. They eat fruits of L. japonicum and P. scandens, digest part of the pericarp, and drop the seeds with their droppongs. Such seeds have a higher percentage of germination. Thus it apears that fruit-eating birds such as the bulbuls is taking part in vegetation changes in the urbanized areas.

Germination Requirements of Lotebush (Ziziphus obtusifolia var. obtusifolia)

Optimum average temperatures for germination of lotebush (Ziziphus obtusifolia var. obtusifolia) seeds in the laboratory were 20? to 30?C. Although some germination occurred without light and without a cold treatment, both of these factors tripled germination when they were present. Aging was unnecessary to obtain optimum germination. Best emergence in the field occurred when average soil temperatures ranged from 22.4? to 27.1? C. These field temperatures are most common in early spring and early fall. Litter enhanced germination in late spring and summer. Timing of precipitation is a limiting factor during the warmest months. Lotebush (Ziziphus obtusifolia var. obtusifolia), a spiny shrub in the Rhamnaceae family, occurs in Texas, Arizona, New Mexico, and northern Mexico. Because of its ability to resprout from both crown and roots, along with its resistance to herbicides (Scifres and Kothmann 1976), lotebush has the potential to increase its cover on Texas rangeland after the release of competition from other woody vegetation by brush control treatments (Carter 1958, Box and White 1969). Moreover, since lotebush spreads by movement of seeds and requirements for germination are unknown, its ecological potential may be seriously underestimated. Temperature is not only a general environmental factor which affects the germination process, but may be a method for breaking the dormancy of some seeds. Seeds of many plants are shed in autumn and are exposed to cold temperatures during the winter while they may also be exposed to moist conditions in the soil or under leaf litter. Schopmeyer (1974) reported that Ziziphusjujuba seeds needed to be stratified for 60 to 90 days at 50 C in moist sand for maximum germination to occur. Light, important for breaking the dormancy of some seeds, is usually most abundant only on the soil surface. Seeds can be characterized by their light requirements as those which: (1) germinate after a brief illumination; (2) germinate only in continuous light; (3) germinate only in darkness; or (4) are indifferent to light during germination (Crocker 1948, Schopmeyer 1974, Mayer and Poljakoff-Mayber 1975). Percentage of creosotebush (Larrea tridentata) seeds which germinate is greater in darkness than in light (Barbour 1968), whereas, germination of big sagebrush (Artemisia tridentata) seeds exposed to full light was greater than when seeds were in the dark (Weldon et al. 1959). The indurante stone in each lotebush fruit has two cells, and each contains a seed resembling an apple (Malus pumila) seed (Lundell 1969). Common methods used to scarify seeds are mechanical abrasion (Schopmeyer 1974, Mayer and Poljakoff-Mayber 1975), passage through the digestive tracts of birds and herbivores (Mayer and Poljakoff-Mayber 1975), and fire (Cushwa et al. 1968). Other methods include acid, boiling water (Quick and Quick 1961, The authors are research assistant and chairman Horn professor, Department of Range and Wildlife Management, Texas Tech University, Lubbock 79409. This research is published as Texas Tech University, College of Agricultural Sciences Publication No. T-9-228. We thank J. W. Chapman and Sons Realtors for allowing us to conduct this study on their property. Manuscript received December 14, 1980. Schopmeyer 1974, Mayer and Poljakoff-Mayber 1975), and exposure to alternating low and high temperatures which cause the seedcoat to contract and expand (Mayer and Poljakoff-Mayber