Search Results

This chapter focuses on cactus-feeding insects and cactus pathogens. In the known cactus-feeding insect community, the Pyralidae (pyralids) are most numerous, with approximately 58 species feeding on cacti, followed by Cerambycidae (long-horned beetles), with about 20 species. The insect pests on Opuntia species vary considerably, depending on the country and the continent in which they are cultivated. The largest number of pests are recorded from Mexico, where Opuntia species are extensively cultivated. In the Mediterranean countries, pathogens cause considerable damage to cultivated plantings comprised mainly of Opuntia ficus-indica and its many cultivars. The most important cactus pear diseases are grouped according to their pathogenic agents. The biotic diseases are caused by bacteria, yeasts, fungi, phytoplasmas, viruses, and phytoplasma/virus-like organisms.

Cacti inhabit a wide diversity of climatic regions and ecosystems. Like many other plants, cacti populations are seriously threatened by habitat destruction and other human activities such as illegal collecting. This chapter examines the biodiversity of both wild and cultivated cacti, and discusses contemporary and long-term issues pertaining to conservation of cacti. It first describes the factors affecting biodiversity of cacti and the estimation of genetic diversity in wild and cultivated cacti, and then discusses the effects of habitat destruction and collection on biodiversity loss of wild cacti. International activities that encourage the conservation of cacti are also presented.

Fruits of vine and columnar cacti are increasingly popular in many countries. This chapter discusses vine and columnar cacti cultivated for their fruits, known as pitahaya or pitaya: pitahaya generally refers to fruits of vine (climbing) species and pitaya to fruits of columnar (erect) ones. The red pitahaya (Hylocereus undatus) is the most popular vine cactus and is a worldwide crop, while the yellow pitaya (Stenocereus queretaroensis) is the most cultivated among the columnar cacti. In the chapter, the cytology, breeding systems, environmental constraints, horticultural aspects, and commercialization of the main cultivated species are examined.

This chapter examines the root biology of cacti, discussing root structure, growth, and development, and then exploring the functions of roots as organs for water, and mineral uptake and plant anchorage. An understanding of the relationship between root structure and function is essential to understanding how cacti roots and root systems have evolved structural and physiological features to help them endure harsh conditions, such as high temperatures, prolonged drought, nutrient-poor soils, and strong winds. For a number of desert and epiphytic cacti, the development of rhizosheaths improve root water relations by ensuring good contact between the root and wet soil, and by helping to reduce water loss from the root to a drier soil. Lateral root primordia arise during drought and hasten plant recovery when soil moisture is restored.

Cacti are important food resources for wild vertebrates. In arid lands, cladodes (pads) and fruits of platyopuntias (prickly pear cacti) are consumed by wild vertebrates in ways that affect entire ecosystems. This chapter presents an overview of the utilization of platyopuntias by wild vertebrates, and also includes a list of the vertebrate species reported to be consumers of platyopuntias.

This chapter explores two myths, the first of which is really an adjunct to the stories on farming and family life. It gives the origin of the cactus wine ceremony, a topic that was treated at the end of the Thin Leather Corn and Tobacco text. The cactus wine ritual is for the purpose of bringing rain, which is best seen in the chanted or orated speeches that are given during the event. Wine feast speeches sometimes also mention drinking, and the subsequent vomiting of cactus wine and rumbling of people's stomachs and bowels. Thus, the humans act in sympathy with the clouds that they hope to attract. To Juan Smith and William Allison, the ceremony is a misuse of saguaros and an excuse for drunkenness. Siuuhu, they say, did not intend saguaro to be used this way.

The Colorado Desert of California represents the northwesternmost portion of the Sonoran Desert, which extends into Arizona, Baja California, and Sonora. This chapter describes the types of vegetation and distribution of dominant plants in the Colorado Desert, presenting vegetation types based on dominant species and on assemblages of species with similar strategies for coping with specific microclimates and soil types. The plant community types of the Colorado Desert include the creosote bush scrub, cactus scrub, saltbush scrub, alkali sink, microphyll woodland, palm oasis, and psammophytic scrub.

Many species of the Cactaceae produce edible fruits. Among the approximately 1,600 species in this family, the genus Opuntia has the most relevant role in agriculture. The cactus pear (Opuntia ficus-indica [L.] Mill.) is cultivated for fruit production in all continents except Antarctica. The main producing country is Mexico, with a production of over 345,000 tons fresh mass year^-1 on about 70,000 ha of specialized plantations. This chapter outlines the basics of cactus pear cultivation, including site selection, cultivars, harvesting, fruit productivity, and fruit quality, and also discusses the economic features, postharvest physiology, and postharvest fruit management.

The West Asia/North Africa (WANA) region has winters with low and erratic rainfall; hot, dry summers; and characterized by high population growth, limited areas of arable land, harsh deserts, and limited water resources for irrigation development. The search for plant species with the ability to grow and produce in arid areas has been a permanent concern in most WANA countries. Such plants must successfully withstand water shortage, high temperature, and poor soil fertility. Cacti, particularly platyopuntias (Opuntia ficus-indica), can satisfy the requirements of a drought-resistant fodder. This chapter focuses on raising cactus fruits, particularly platyopuntias, for forage and fodder in the WANA region; discusses the use of cacti as fodder; and examines the integration of platyopuntias with other feed resources in the WANA region.

This chapter discusses some of the important uses of the cactus plant. Cacti are important as a vegetable, as a dietary supplement, and as the host for the red-dye-producing cochineal. A common use of cactus stems is nopalitos—tender young cladodes—a traditional vegetable eaten fresh or cooked in various dishes. Nopalitos are generally obtained from Opuntia ficus-indica, Opuntia robusta, or Nopalea spp, and contain complex polysaccharide mucilage, which has great potential as part of dietary fiber. The production of cladode products as over-the-counter medicinal products is growing fast. Cladode-derived products are sold for the control of diabetes, cholesterol, gastric and intestinal afflictions, and obesity. Two types of cochineal, the dye-producing cactus parasite, are also recognized.

Cacti are well adapted to arid and semiarid regions where food and fodder crops are limited. Their ability to thrive in these environments makes them of immediate interest to breeders and molecular biologists seeking to develop crops for areas unsuitable for conventional agriculture. This chapter focuses on plant breeding and biotechnology research on the fruit-bearing group Opuntia, although the techniques, methods, and concepts presented are transferable to most of the Cactaceae. The objectives of breeding and biotechnology include the following: (1) expanding the production area into new environments, (2) improving the quality and productivity of cacti to expand into new markets, and (3) adding new traits to allow the development of new uses for cacti. The chapter also reviews the molecular work done on cacti and proposes a plan for the development of molecular tools for cacti utilizing the work done on traditional crop species.

This chapter discusses the anatomy and morphology of cacti shoot, focusing primarily on its cellular characteristics and biomechanical properties. The shoot consists of internodes, nodes where leaves are attached, and axillary buds (the spine-producing areoles). The bud scales and leaves of axillary buds are the signature spines of cacti. The ability of cacti to adapt to xeric conditions is due to increases in water-storage tissue, especially in the cortex and wood, thickened cuticles, and the presence of a hypodermis. The fundamental tissue, cortex and pith, carries out two important functions related to xeric adaptations: photosynthesis and water storage.

This chapter discusses gas exchange and other environmental responses of cacti. It focuses on net CO₂ uptake and examines the influence of three key environmental factors—temperature, soil moisture, and solar irradiation absorbed by photosynthetic pigments, i.e., the photosynthetic photon flux (PPF)—on CO₂ uptake by Opuntia ficus-indica. The response of net CO₂ uptake by Opuntia ficus-indica to these three variables is important for predicting its productivity under any environmental condition and serves as a model for assessing the net CO₂ uptake, and hence the potential biomass productivity, of other cacti.

This chapter focuses on the reproductive adaptations of cacti to arid environments to explain the evolution of reproductive mechanisms that allow cacti to endure harsh conditions. It describes the available information on reproductive biology, relating various aspects to the adaptations of cacti to aridity and to the origin and causes of biological variation. Among the Cactaceae, Opuntia spp. are the best examples of reproductive versatility using a wide array of sexual and asexual methods. This reproductive versatility plays an important role in the ecological strategy of adaptation to aridity.

Cacti show considerable diversity of life form in tropical and subtropical America. Species diversity increases considerably toward the tropics, Mexico being the most important center, with 850 species and 54 genera. This chapter considers the key aspects in the population and community ecology of cacti. It examines how abiotic and biotic factors interact to influence the distribution and abundance of a particular species, leading to particular survivorship, fecundity, growth patterns, and groups of species, with an emphasis on the maintenance of biodiversity. To understand the population dynamics of cacti, the relative importance of abiotic and biotic factors should be assessed. The chapter also analyzes the geomorphic history of the localities in which populations of cacti occur to understand population dynamics at the landscape level.

Biogeographers study the distributions of organisms and the systems those species inhabit. Biogeography can be viewed both as a form of geographical enquiry applied to plants and animals, and also as a biological science concerned with geography. Thus, biogeography is interdisciplinary, like other “composite” sciences such as geomorphology (Bauer 1996; Osterkamp and Hupp 1996). Veblen (1989) provided an overview of biogeography in the late 1980s. He commented on the nature of biogeography as practiced in academic geography programs, finding most similarity in approach and subject matter with ecologists and ecology. Three broad research orientations can be identified (K. R. Young 1995): ecological, evolutionary, and applied. Each orientation includes both theoretical frameworks and empirical foundations. Ecological approaches relate plant and animal distributions to current biological and physical processes, including interactions among species, precipitation and temperature regimes, and soil nutrient dynamics. Evolutionary approaches accommodate genetic and population changes in species over long time-periods, in addition to historical processes as affected by Earth history, plate tectonics, and climate change; these approaches have been labeled as “classical biogeography” (Veblen 1989). Complete biogeographical explanations often require detailed information on both ecological conditions and historical changes over centuries or millennia or even millions of years. Biogeographical approaches also are applied to the evaluation of important societal issues, for example through the study of nature reserves. Of practical and theoretical concern are situations where species or their distributions and abundances are modified by human influences. This is the part of biogeography closest to geography’s mainstream research interests in human–nature interrelations, and is called “cultural biogeography.” Some people characterize geography as the study of the Earth as modified by humans; in this case, biological geography (biogeography) would include the study of how species and living land cover have been altered by people. Species distributions can change over short and long time-scales (Hengeveld 1990; Dingle 1996). Biogeographers who study the shifting spatial distribution patterns of specific species of plants or animals often focus their research on biophysical factors that determine the range limits of the species and how those factors change through time. These controls include the effects of other organisms, the physical conditions of the environment, and disturbance.

This chapter shifts the focus of Southwest history back to New Mexico as it analyses the memoir, We Fed Them Cactus, written by Nuevomexicana cultural broker, Fabiola Cabeza de Baca. The memoir allows Cabeza de Baca to (re)claim her herencia, or inheritance, as she documents the historical implications of U.S imperialism and the ways in which she suffers the impacts of physical and cultural displacement in the burgeoning U.S. Southwest. This chapter also argues that Cabeza de Baca employs a unique narrative style and voice that is androgynous – a tactic that allows her access to the masculine space of historical documentation and storytelling that was then dominated by men. Through her work, Cabeza de Baca preserves the stories of her Hispano New Mexican past, she attempts to maintain a social structure on the verge of loss, and she demonstrates her querencia, or deep abiding love for her homeland.

Whether you are breaking prairie sod in the nineteenth century or raising a family and scrambling to make ends meet in the twenty-first, it is hard to get worked up over abstract possibilities. There is too much that needs doing, right here, right now. Even knowing the odds, people still live in earthquake zones, hurricane alleys, and the unprotected floodplains of mighty rivers. The warm embrace of a thirsty aridland city is not so different. Generally speaking, it is hard for any of us to get seriously concerned about what might happen until it does happen. That’s why the politics of climate change are so difficult. The measurements and observations that convince scientists about the warming of Earth are invisible to the rest of us. We fail to sense them at the scale of our personal lives. And believing in the verdicts of computer models about what might happen twenty or forty years in the future, well, that is tantamount to a leap of faith, and most people don’t ordinarily jump that far. Believing in the growth of cities can be difficult, too. Beginning in 2007, the domino of subprime mortgage defaults knocked over the domino of overleveraged investment banks, which toppled a wobbly world credit system, which upended industries around the globe and ushered in the Great Recession. 1 The home-building industries of growth-crazy cities like Las Vegas and Phoenix collapsed virtually overnight. Suburbs from Florida to California became ghost towns where wind-driven litter piled up in doorways and weeds grew higher than the sills of boarded-up windows. Some analysts predicted the emergence of a new generation of suburban slums and the death of gas-guzzling, car-dependent, long-commute suburban lifestyles. 2 Indeed, in the long run, considering the implications of peak oil and peak water and the likelihood of more severe climate reckonings than we’ve yet seen, such a demise seems likely—though maybe not quite yet.

This chapter describes general characteristics and components of the energy and water balances in arid regions, with specific examples from the Jornada Basin. Various research efforts to characterize the energy and water balances and resultant carbon dioxide fluxes in the Jornada Basin are detailed. We provide a brief overview of how plant physiology interacts with energy and water balances in this region, and characterize general abiotic conditions and some physiological traits of plants in this arid region. The surface of a landscape may be considered as a layer with some amount of vegetation. More general descriptions divide the vegetation, like the soil, into layers, but the concern here is energy balance at the interface with the atmosphere. The net energy balance of the land surface is determined by inputs (radiant energy), outputs (reflection [i.e., albedo], emission of longwave radiation, convective heat transfer to the atmosphere [i.e., sensible heat flux], evapotranspiration of water [i.e., latent heat flux], and conduction of heat into soil), and changes in heat storage. The balance of these terms is adjusted as the surface temperature comes into steady state or nearly so. Increased solar input will drive surface temperatures higher until longwave emission and other losses come into a new balance. The net energy input, as inputs minus outputs, may be stated formally as an energy-balance equation . . . Rate of heat storage = S = Q+sw + Q+TIR − Q+TIR _ Q_E Q_H − Q_S, (8-1) . . . where the superscript + indicates an input, and − indicates an output or loss, and all terms are expressed as flux density in units of W/m2. Q+SW is the energy added to the surface layer by solar radiation from above. Q+TIR is the thermal infrared radiation emitted by gases in the atmosphere, principally water vapor and CO2, whereas Q_TIR is the thermal infrared radiation emitted from components of the Earth’s surface and lost back to the atmosphere. Q_E is the latent heat flux from the heat of vaporization of water vapors resulting from soil evaporation (E) and plant transpiration, generally measured as the composite evapotranspiration flux (ET).