The Science of Grapevines

Anatomy and Physiology

Markus Keller

• Publisher: Academic Press
• Year: 2015
• ISBN:
  9780124200081
• Edition: 2
• Topic: Tecnologia e ingegneria
• Subtopic: Scienze dell'alimentazione

The Science of Grapevines: Anatomy and Physiology is an introduction to the physical structure of the grapevine, its various organs, their functions and their interactions with the environment. Beginning with a brief overview of the botanical classification (including an introduction to the concepts of species, cultivars, clones, and rootstocks), plant morphology and anatomy, and growth cycles of grapevines, The Science of Grapevines covers the basic concepts in growth and development, water relations, photosynthesis and respiration, mineral uptake and utilization, and carbon partitioning.

These concepts are put to use to understand plant-environment interactions including canopy dynamics, yield formation, and fruit composition, and concludes with an introduction to stress physiology, including water stress (drought and flooding), nutrient deficiency and excess, extreme temperatures (heat and cold), and the impact and response to of other organisms.

Based on the author's years of teaching grapevine anatomy as well as his research experience with grapevines and practical experience growing grapes, this book provides an important guide to understanding the entire plant.

• Chapter 7 broken into two chapters, now "Environmental Constraints and Stress Physiology and Chapter 8 "Living with Other Organisms" to better reflect specific concepts
• Integration of new research results including:
• • Latest research on implementing drip irrigation to maximize sugar accumulation within grapes
  • Effect of drought stress on grapevine's hydraulic system and options for optimum plant maintenance in drought conditions
  • The recently discovered plant hormone – strigolactones – and their contribution of apical dominance that has suddenly outdated dogma on apical dominance control
• Chapter summaries added
• Key literature references missed in the first edition as well as references to research completed since the 1e publication will be added

Chapter 1

Botany and Anatomy

The diverse species of grapevine belong to the botanical family Vitaceae, which includes mostly shrubs and woody lianas that climb using leaf-opposed tendrils. The vast majority of the thousands of grape cultivars belong to the species Vitis vinifera. Some of the other species are used as pest-tolerant rootstocks to which cultivars with desirable fruit properties are grafted. Cultivars are propagated asexually as cuttings so that each individual is a clone of its mother plant. Grapevines comprise vegetative organs (roots, trunk, cordon, shoots, leaves, and tendrils) and reproductive organs (clusters with flowers or berry fruit). All organs are interconnected through the vascular system comprising the xylem for water and nutrient transport, and the phloem for assimilate transport. The roots form the plant–soil interface, while the trunk, cordons, and shoots of a vine form its stem. The shoots carry the leaves, buds, tendrils, and clusters. Leaves are arranged in spiral phyllotaxy in juvenile vines and in alternate phyllotaxy in mature vines. Buds are young, compressed shoots embedded in leaf scales. Tendrils and clusters are modified shoots. After fertilization, the flower pistil develops into the berry fruit. The berry comprises up to four seeds surrounded by the endocarp, the mesocarp or flesh, and the exocarp or skin.

Keywords

Bud; clone; cultivar; grape berry; leaf; root; rootstock; shoot; tendril; Vitis

Chapter Outline

1.1 Botanical Classification and Geographical Distribution 2

1.2 Cultivars, Clones, and Rootstocks 10

1.2.1 Variety Versus Cultivar 10

1.2.2 Cultivar Classification 17

1.2.3 Clones 19

1.2.4 Rootstocks 21

1.3 Morphology and Anatomy 24

1.3.1 Root 26

1.3.2 Trunk and Shoots 33

1.3.3 Nodes and Buds 41

1.3.4 Leaves 44

1.3.5 Tendrils and Clusters 50

1.3.6 Flowers and Grape Berries 52

1.1 Botanical Classification and Geographical Distribution

The basic unit of biological classification is the species. According to the “biological species concept,” a species is defined as a community of individuals—that is, a population or group of populations whose members can interbreed freely with one another under natural conditions but not with members of other populations (Mayr, 2001; Soltis and Soltis, 2009). In other words, such communities are reproductively isolated. Although each individual of a sexual population is genetically unique, each species is a closed gene pool, an assemblage of organisms that does not normally exchange genes with other species. Their genes compel the individuals belonging to a species to perpetuate themselves over many generations. Yet all life forms on Earth are interrelated; they all ultimately descended from a common ancestor and “dance” to the same genetic code, whereby different combinations of three consecutive nucleotides of each organism’s deoxyribonucleic acid (DNA) specify different amino acids that can be assembled into proteins. Because they are thus interrelated, organisms can be grouped according to the degree of their genetic similarity, external appearance, and behavior. In the classification hierarchy, closely related species are grouped into a genus, related genera into a family, allied families into an order, associated orders into a class, similar classes into a division (plants) or a phylum (animals), related divisions or phyla into a kingdom, and, finally, allied kingdoms into not an empire but a domain. The “evolutionary species concept” recognizes this ancestor–offspring connection among populations that may follow distinct evolutionary paths to occupy separate ecological niches but may continue to interbreed for some time (Soltis and Soltis, 2009). For example, although they have been geographically isolated for over 20 million years, Eurasian and North American Vitis species are still able to interbreed readily.

As is the case with many plants, the species of the genus Vitis are not very well defined because of the extreme morphological variation among and within populations of wild vines (Currle et al., 1983; Hardie, 2000; Mullins et al., 1992). This implies the following: (i) all Vitis species are close relatives that share a relatively recent common ancestor and (ii) evolution is still at work, throwing up new variants all the time (see Section 2.3). Many vine species are actually semispecies—that is, populations that partially interbreed and form hybrids under natural conditions, which is in fact common among plants and may be an important avenue for the evolution of new species (Soltis and Soltis, 2009). Despite some hybridization where their natural habitats overlap, however, the various Vitis gene pools usually stay apart so that the populations remain recognizably different. Nonetheless, species that occur in close proximity are more similar than distant species in similar habitats. Grapevines are a good example of the limits of taxonomic systems, demonstrating that there is a continuum of differentiation rather than a set of discrete, sexually incompatible units. As early as 1822, the Rev. William Herbert asserted that “botanical species are only a higher and more permanent class of varieties,” and in 1825 the geologist Leopold von Buch postulated that “varieties slowly become changed into permanent species, which are no longer capable of intercrossing” (both cited in Darwin, 2004). A few decades later, Charles Darwin expressed it clearly: “Wherever many closely allied yet distinct species occur, many doubtful forms and varieties of the same species likewise occur” and, furthermore, “there is no fundamental distinction between species and varieties,” and, finally, “varieties are species in the process of formation” (Darwin, 2004). Indeed, modern genetic evidence indicates that the various Vitis species evolved relatively recently from a common ancestor so that they have not yet had time to develop the complete reproductive isolation that normally characterizes biolog...