Chilopsis Research Articles

Estimating Transpiration for Three Woody Ornamental Tree Species using Stem-flow Gauges and Lysimetry

We compared transpiration estimates of three common desert landscape tree species using stem-flow gauges and lysimetry. Argentine mesquite (Prosopis alba Grisebach), desert willow [Chilopsis linearis (cav.) Sweet var. linearis], and southern live oak (Quercus virginiana Mill., seedling selection) were subjected to three irrigation regimes. Leaching fractions of +0.25, 0.00, and -0.25 were imposed for 2 years. During the summer of the second year, we conducted a comparative transpiration study. Trees growing in 190-liter plastic containers had a highly linear correlation (r = 0.98, P = 0.001) between transpiration estimated by stem-flow gauges and lysimetry. An average 18% error was measured between paired data (total runs of 14 to 72.5 hours) of stem-flow gauge and lysimetry transpiration estimates. However, a lower error was correlated significantly with longer run times (r = -0.37, P = 0.05). Based on field measurements taken in this experiment, run times would have to be >68 hours to maintain an associated error below 10%. Higher cumulative transpiration also was associated with longer run times (r = 0.80, P = 0.001). These results suggest that the stem-flow gauge can be used to estimate transpiration accurately to schedule irrigation for woody ornamental trees in an arid environment, provided that irrigation predictions are not based on short-term stem-flow gauge estimates (<68 hours).

VERIFICATION OF AN INTERGENERIC HYBRID BETWEEN DESERT WILLOW AND CATALP A

Desert willow (Chilopsis linearis) is native to the arid southwestern U.S. and is used as a landscape shrub. Catalpa (Catalpa bignonioides) is a small tree common in the southern U.S. that is used as a landscape plant. Both species have showy flowers and are members of the Bignoniaceae family. Controlled crosses were made using pollen from a single catalpa tree and desert willow stigmas of the cv. `Marfa Lace'. Fruit developed normally and seven seedlings were produced that had leaf morphology intermediate between the parents. From starch gel electrophoresis, putative hybrids had isozyme banding patterns consistent with hybridization between the parent species. A second biochemical verification is being conducted using probes for ribosomal RNA genes.

‘White Storm’ and ‘Dark Storm’ Desert Willow

Abstract Desert willow [Chilopsis linearis (Cav.) Sweet.] (7, 12) is a facultative phreatophyte (a plant whose roots will extract water from underground streams, a water table, or perched sources, or the strata immediately above these sources, but which can also function well in the absence of these water supplies). It is a tall shrub to a small tree (2, 3) and is native to the American southwest, from Baja California, southern California, southern Nevada, Arizona, and New Mexico to southwestern Texas and northern Mexico (8, 9).

‘Marfa Lace’, ‘Alpine’, and ‘Tejas’ Desert Willows

Abstract ‘Marfa Lace', ‘Alpine’, and ‘Tejas’ are new desert willow [Chilopsis linearis (Cav.) Sweet.] cultivars selected at the Texas A&M Research and Extension Center at El Paso and approved for release by the Texas Agricultural Experiment Station. Desert willow is a deciduous flowering shrub or tree native to the southwestern United States. The species exhibits considerable variability in floral color, but this generally has not been exploited through selection or breeding. The advantages of these new selections include large, semi-double flowers in ‘Marfa Lace’, large leaves and dark flowers in ‘Alpine’, and even larger flowers in ‘Tejas’. To my knowledge, no other semi-double desert willow has been released.

The failure of nitrogen and lignin control of decomposition in a North American desert.

We measured mass losses of both buried and surface litter of six litter types: leaves of the perennial evergreen shrub, Larrea tridentata, leaves of the winter deciduous perennials Fluorensia cernua, Prosopis glandulosa and Chilopsis linearis (a desert riparian species), an evergreen monocot, Yucca elata, and a mixture of annual plants. These species differed in lignin content and carbon-nitrogen ratios. There was no correlation between rates of mass loss and percent lignin, carbon-nitrogen ratio, or lignin-nitrogen ratio. The leaves of F. cernua and the mixed annuals exhibited the highest rates of mass loss. Surface litter of Y. elata, the mixed annuals and C. linearis exhibited higher mass loss than buried litter of the same species. The patterns of mass loss of buried and surface litter differed with buried litter mass loss occurring as a negative exponential and surface litter exhibiting low rates in winter and spring and high rates in summer. There was no correlation between mass loss in surface bags that were field exposed for 1 month and actual evapotranspiration (AET) but there was a correlation between AET and mass losses in buried litter. A model relating mass loss to AET and initial lignin content underestimated mass losses in all species examined.

Comparative Water Relations of Phreatophytes in the Sonoran Desert of California

The seasonal and diurnal water relations were compared among six desert phreatophytes, two evergreen shrubs, and one deciduous shrub. All species were located in one wash woodland in the Sonoran Desert of southern California. There are several mechanisms by which these Phaenicia have adapted to the desert environment. One group of winter—deciduous phreatophytes (Olneya tesota, Prosopis glandulosa, and Acacia greggii) experienced summer midday leaf water potentials below —4.0 MPa. These phreatophytes had a series of physiological mechanisms for tolerating summer water stress, including seasonal and diurnal osmotic adjustment and the maintenance of high leaf conductance at low leaf water potential. Osmotic adjustment of these three phreatophytes was similar to or greater than that of two evergreen species (Larrea tridentata and Simmondsia chinensis). Dalea spinosa, a stem—photosynthetic phreatophyte, avoided water stress by maintaining a very small leaf area. The summer—deciduous phreatophytes (Hyptis emoryi, and Chilopsis linearis) demonstrated mechanisms of drought avoidance such as change in leaf biomass and low summer leaf conductance. Little osmotic adjustment occurred in the summer—deciduous phreatophytes. The phreatophytic species studied in this investigation have evolved adaptations to water stress that are similar to those of deciduous and evergreen shrubs of the Sonoran Desert. Desert phreatophytes are a complex group of species with varied adaptive mechanisms to tolerate or avoid drought and should not be considered simply as a group of species that avoid desert water stress by utilizing deep ground water unavailable to other desert species of drought tolerance and avoidance.

An experimental study of floral display and fruit set in Chilopsis linearis (Bignoniaceae).

To examine the effects of pollen and resource availability on floral display and fruit set in Chilopsis linearis three different types of experimental manipulations were performed. Pollen availability to individual inflorescences was altered by combinations of hand-pollinations and/or pollinator exclusions. Number of flowers produced per inflorescence was determinate; it was not affected by pollination, although flowers of the unpollinated treatment lasted longer. Fruit set was increased over natural levels by an average of 540% by hand-pollinating individual inflorescences. There was also a negative correlation between inflorescence size and percent fruit set in all treatments tested. Attempts to vary resources available to individual inflorescences and entire trees showed no significant effect on fruit set. These results show that, at the level of individual inflorescences, fruit and seed production in Chilopsis linearis are pollen limited and not resource limited. The problem of testing for resource limitation of female reproductive success in iteroparous plants and the effect of inflorescence size on female components of fitness are also discussed.

13C nuclear magnetic resonance spectroscopic analysis of seed oils containing conjugated unsaturated acids

Abstract13C Nuclear magnetic resonance spectroscopy has been used in a nondestructive investigation of conjugated unsaturated acids in seed oil triacylglycerols. Spectra of seven seed oils, fromPunica granatum, Cucurbita palmata, Jacaranda mimosifolia, Centranthus ruber, Catalpa bignonioides, Chilopsis linearis andCalendula officinalis, containing among them six isomeric trienoic acids,cis,trans,cis‐ andtrans,trans,cis‐8,10,12‐,cis,trans,cis‐, cis,trans,trans‐, trans,trans,cis‐ andtrans,trans,trans‐9,11,13‐octadecatrienoic acids, and of the oil ofImpatiens balsamina containingcis,trans,trans,cis‐9,11,13,15‐octadecatetraenoic acid, have been examined. Structures of component acids were derived from shifts of double bond carbons and of carbons close to the double bond systems. Compositions of the oils were obtained from signal intensities. Results were similar to those obtained by older methods. Only oil ofCentranthus ruber contained more than one major conjugated acid; bothcis,trans,trans‐ andtrans,trans,trans‐9,11,13‐octadecatrienoic acids were found. The latter acid is now thought to occur naturally.

‘Hope’ Desertwillow1

Abstract Desertwillow Chilopsis linearis (Cav.) Sweet is native of Western Texas to southern California and southward to Mexico with ornamental value in New Mexico (1, 2). ‘Hope’ desertwillow was released for use as a native ornamental in 1980 by New Mexico State University Agricultural Experiment Station and the USDA, Soil Conservation Service, Plant Materials Center at Los Lunas, NM.

Competition between Hummingbirds and Insects for the Nectar of Two Species of Shrubs

The nectars of two species of shrubs, Ribes pinetorum and Chilopsis linearis, were limited food resources that were utilized by both hummingbirds and insects. Both shrub species had bimodal patterns of daily nectar secretion with peaks in morning and afternoon. Ribes pinet- orum, blooming at high altitude, was visited frequently by hummingbirds because its timing of nectar secretion coincided with periods of low temperature when insects were inactive. Sufficient nectar accumulated in flowers to make hummingbird foraging economical in early morning and late afternoon, but not at midday when insects were foraging and had lowered nectar levels. Chi- lopsis linearis, blooming at lower elevations where low temperatures did not inhibit insect activ- ity, attracted increasing numbers of bumblebees which depleted nectar levels and virtually excluded hummingbirds. The present study provides another example of competition between ver- tebrates and insects, and suggests that this interaction between distantly related taxa may play a significant role in plant-pollinator coevolution as well as in community ecology. Although many species of flowering plants have coevolved highly specific relationships with animal pollinators (Faegri and van der Pijl, 1971; Grant and Grant, 1965, 1968; Proctor and Yeo, 1972; van der Pijl and Dodson, 1967). Others are relative generalists. They may be pollinated by several animal taxa which forage for their nectar or pollen. Animals may compete for these food resources. Competition for floral rewards between individuals of closely related species is well documented and is thought to play a major role in the organization of guilds of nectar-feeding animals (e.g., Feinsinger, 1976; Heinrich, 1976; Inouye, 1978; Gill, 1978; Gill and Wolf, 1975; Kodric- Brown and Brown, 1978; and many others). Several recent studies have sug- gested that organisms in different classes and phyla compete for food and other resources (e.g., Brown and Davidson, 1977; Reichman, 1979). Since two classes of vertebrates (birds and mammals) and several orders of insects (Hymenoptera, Lepidoptera, Diptera, and Coleoptera) commonly feed on nectar or pollen and serve as pollinators, competition between these dis- tantly related taxa may play a significant role in the ecological relationships among these flower visitors and in the coevolution of plants and their polli- nators (Carpenter, 1979; Kodric-Brown and Brown, 1979). In the present paper we assess competition between hummingbirds and bees for the nectar of two Southwestern shrubs, Ribes pinetorum Greene (Saxifragaceae), orange gooseberry, and Chilopsis linearis (Cav.) Sweet, (Bignoniaceae), desert willow.

Vegetative and Reproductive Growth Patterns in Desert Willow (Chilopsis linearis (Cav.) Sweet)

The patterns of leaf and fruit production of desert willow, Chilop- sis linearis (Cav.) Sweet, in relation to temperature and precipitation patterns in the Chihuahuan Desert of southern New Mexico were examined by harvesting shoot samples monthly during four growing seasons. On a site with 1.1 individuals per hectare, leaf production was about 5 kg-ha-1 and fruit production was about 1 kg-ha-1 in two years with dry springs and moist summers. In a year with a moist spring and a moist summer, leaf and fruit production was doubled. This high rate of production in the field during favorable periods supports previous laboratory studies that Chilipsis has a high acclimation potential under cool to moderate tem- peratures. However, in a year with a hot, dry spring and summer Chilopsis was adversely affected. This also supports previous studies that the net photosynthesis rate of Chilopsis was greatly reduced under high preconditioning temperatures and rapidly decreased as water potentials dropped below - 10 bars. Desert willow, Chilopsis linearis (Cay.) Sweet, is a small, deciduous tree. It varies from 4 to 9 m in height, with numerous long branches and willow-like leaves. The white flowers are orchid-shaped with purple stripes. The fruits are 10 cm or more long, and narrow, with wings of the seeds dissected into hairs (Kearney and Peebles 1960). Chilopsis occurs throughout the desert areas of the southwestern U.S. and northern Mexico (Hastings, Turner and Warren 1972). In the Sonoran desert, it occurs along the larger drainage channels with mesquite and other species requiring the more favorable moisture con- ditions of this riparian habitat (Shreve 1964). In the southern New Mexico region of the Chihuahuan desert, it is also restricted to larger drainages. Freeman and Dick-Peddie (1970) found Chilopsis in lower elevation riparian habitats of the Sacramento Mts., but not in similar habitats of the Black Range. Gardner (1951) found it in large arroyos and tributaries to the Rio Grande from the mouth of the Rio Puerco south to Las Cruces. Balding and Cunningham (1974) described the

Coevolution of Foraging in Bombus and Nectar Dispensing in Chilopsis : A Last Dreg Theory

Flowers of Chilopsis linearis dispense nectar into pools and grooves. The bumblebee, Bombus sonorus, extracts pool nectar at a rate seven times faster than groove nectar. The result is the coevolution of a plant-pollinator system in which bees, while foraging efficiently, increase the number of flowers visited per calorie of nectar reward provided by the plant.

The Effect of Decreasing Water Potential on Net CO2 Exchange of Intact Desert Shrubs

This study compares the effects of seasonal (in situ) and experimentally—induced drought on three desert shrubs of different growth types. The effect of decreasing water potential on CO2 uptake was used as the response indicating differences in desert adaptation. Larrea divaricata Cav., Encelia farinosa Gray, and Chilopsis linearis Cav. were selected as representing evergreen, drought—deciduous, and winter—deciduous species respectively. Field measurements of water potential and photosynthesis were made simultaneously on plants of all three species. Data were collected in the field at monthly or bimonthly intervals for a year. Additional experiments were conducted in a transplant garden and under controlled environments in a phytotron. Larrea has a high protoplasmic tolerance to drought stress and maintains net photosynthesis throughout extended periods of low water potential. The photosynthetically active period of Encelia is prolonged, and water loss reduced, by seasonal leaf variability and the drought deciduous habit. These phenomena permit a greater photosynthetic efficiency over a wider range of water potentials than would be possible with a single leaf type. Decreasing water potentials affect Chilopsis the most, but the presence of xeromorphic leaf tissue augments the phreatophytic habit in maintaining relatively high water potentials. A transpiration—retarding mechanism in Chilopsis is also hypothesized.

Effect of Past an Prevailing Temperatures on the Carbon Dioxide Exchange Capacities of Some Woody Desert Perennials

The effect of temperature preconditioning on the net photosynthesis and dark respiration of four woody desert perennials (Larrea divaricata, Hymenoclea salsola, Encelia farinosa, and Chilopsis linearis) was analyzed. After the establishment of stem cuttings or field transplants in a greenhouse, the plants were preconditioned at daytime temperatures of 15°, 30°, or 40°C in a growth chamber for 7—17 days. Carbon dioxide exchange capacities wer then determined at various temperatures. There were distinct species differences in response to the preconditioning treatments which could be correlated with differences in distribution and ecology.

OCCURRENCE OF trans-9-trans-12-OCTADECADIENOIC ACID AS A SEED OIL COMPONENT

trans-9-trans-12-Octadecadienoic acid was found to be a component of the glyceride oil of the seeds of Chilopsis linearis (Cav.) Sweet. It was isolated by fractional crystallization of the acids at low temperatures and removal of conjugated acids as their adducts with maleic anhydride. Identification was made by absorption spectra and by preparation of derivatives and degradative products. The acid is estimated to constitute about 15% of the total fatty acids of the oil. Linoleic acid was also identified.

Contribution to the Causal Anatomy of the Desert Willow, Chilopsis linearis

American Journal of BotanyVolume 22, Issue 3 p. 333-343 Article CONTRIBUTION TO THE CAUSAL ANATOMY OF THE DESERT WILLOW, CHILOPSIS LINEARIS F. Murray Scott, F. Murray Scott University of California at Los AngelesSearch for more papers by this author F. Murray Scott, F. Murray Scott University of California at Los AngelesSearch for more papers by this author First published: 01 March 1935 https://doi.org/10.1002/j.1537-2197.1935.tb05023.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume22, Issue3March 1935Pages 333-343 RelatedInformation