341 Chapters
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9 Grapevine Pests, Diseases and Disorders

Glen L. Creasy and Leroy L. Creasy CAB International PDF

9

Grapevine Pests, Diseases and Disorders

There are a wide range of situations where grapevines and their fruit can be put in jeopardy. This is important not only because of vine health reasons, but also for the economic health of the business. Therefore, minimizing vine exposure to the adverse effects of biotic and abiotic origin is essential.

Pests cause or have a significant potential to cause loss. There are many, many different organisms in the environment, but none are considered pests unless they cause a problem. Despite this, grapevines have many pests and thus problems. Depending on the climate, a large proportion of ongoing vineyard costs can be devoted to managing diseases and pests, and with good reason. Many pests are difficult to suppress and in most cases it is best to adopt a tolerance approach and accept some damage. The point where the cost in money or time is greater than the economic return from the practice is called the economic threshold. The economic threshold, however, varies with pest, location and end use of the grapes. For example, if the consumer sees the actual fruit, then its appearance is very important, whereas this is not so important if the grape is to be processed.

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Chapter 16 Family Brassicaceae

Welbaum, G.E. CAB International PDF

16

Family Brassicaceae

Botany

Brassicaceae is a very important family with over

1,800 species from more than 100 genera worldwide including many important vegetable, field, and oil crops (Table 16.1). Members of this family are also sometimes referred to by their archaic family name Cruciferae or are called crucifers for short (Nieuwhof, 1969; Rubatzky and Yamaguchi,

1997).

Plant and Flower Characteristics

The word Cruciferae means cross in Latin. The family was so named originally because of the characteristic cross-shaped flowers shared by all members of this family. Close examination reveals that each floret has four opposed flower petals that form a square cross (Fig. 16.1). Flower petals vary widely in color among species and may be white, cream, pink, or purple (Nieuwhof, 1969).

The flowers are bisexual with one pistil, and four long and two short stamens on each flower for a total of six. A superior ovary develops into a long fruit pod called a silique, 4.5–10 cm (2–4 in) in length, with a thin, translucent inner membrane, the replum, that separates the two chambers of the pod, and to which the seeds are attached (Fig. 16.2;

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Medium 9781845939076

10 A Brief Appraisal of Genus Potamogeton L. in the Kashmir Valley

CAB International PDF

10

A Brief Appraisal of Genus

Potamogeton L. in the Kashmir

Valley

Aijaz Hassan Ganie, Zafar A. Reshi and B.A.

Wafai

Department of Botany, University of Kashmir, Srinagar, Jammu and Kashmir, India

Introduction

The genus Potamogeton (Potamogetonaceae) is distributed worldwide (Chambers et al.,

2008) and is represented by 69 species and

50 natural hybrids (Weigleb and Kaplan,

1998). The number of species existing in different continents of the world and those shared by various continents are summarized in Table 10.1. The largest number of species

(29) of the genus inhabit aquatic ecosystems in Asia, followed by North America (28 species) and Europe (22 species). Nine species are common to Asia and North

America, 14 to Asia and Europe and 11 are shared by North America and Europe. The high species diversity of the genus in the northern hemisphere indicates that this region could be the centre of diversity and origin of the genus (Lindqvist et al., 2006). A relatively higher number of species of this

genus has also been recorded in central, eastern and western USA, Canada, temperate

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4. Cell-wall Metabolism and Softening during Ripening

P Nath;  M Bouzayen; A K Mattoo CAB International PDF

4

Cell-wall Metabolism and Softening during Ripening

Mark L. Tucker*

US Department of Agriculture, Beltsville, MD, USA

4.1 Introduction

The final stage of fruit development is ripening, which typically includes transformation from an inedible hard organ into a palatable softer version. Fruit softening is a combination of changes in firmness and texture. Firmness can be defined as compressibility or the force required to deform the surface of the fruit (Brookfield et al.,

2011). Texture is defined as a sensory attribute and is more difficult to measure with instrumentation (Mohamed et al.,

1982; Garcia-Ramos et al., 2005; Brookfield et al., 2011). Texture includes crispness, viscosity and juiciness (Brookfield et al.,

2011). Texture is often best measured by human tasters (Brookfield et al., 2011).

Before moving on to the specific details of what happens during ripening to contribute to softening, let us identify a few basic principles to help visualize what softening really is. The edible parts of fruit are not woody (lignified), not even before they ripen. In other words, the cell walls in the edible parts of fruit are not rigid. They can flex. The flexibility of the cell wall is more obvious in thinner structures like leaves. Leaves are not as ‘stiff as a board’.

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8: The Impact of Ozone Pollution on Plant Defence Metabolism: Detrimental Effects on Yield and Quality of Agricultural Crops

Chakraborty, U., Editor CAB International PDF

8 

The Impact of Ozone Pollution on Plant

Defence Metabolism: Detrimental Effects on

Yield and Quality of Agricultural Crops

Fernanda Freitas Caregnato,1* Rafael Calixto Bortolin,1

Armando Molina Divan Junior2 and José Cláudio Fonseca Moreira1

1

Department of Biochemistry, Center for Oxidative Stress Research,

Federal University of Rio Grande do Sul (UFRGS), Porto Alegre; 2Laboratory of Plant Bioindication, Center of Ecology, UFRGS, Porto Alegre, Brazil

Abstract

Over the past decades, research on the negative effects of air pollutants on agricultural crops and agro-­ ecosystems point out for emission reduction strategies, with practical recommendations to increase the sustainability of agricultural and land management in an environment that is constantly changing. Agricultural production will need to keep pace with the growing food demand, which depends on many factors, including the future levels of air pollution, such as tropospheric ozone. The risk of negative effects of ozone on crop productivity created the need to improve our understanding on the mechanisms underlying ozone toxicity, and biotechnological advances are now starting to provide us with the necessary knowledge to safely develop and/or select crops varieties better adapted to ozone stress. Ozone phytotoxicity arises mainly because of its high oxidation potential to generate reactive oxygen species (ROS) in exposed plant tissue. After entering leaf stomata, ozone rapidly degrades into various ROS species, and plants reduce the oxidative damage by activation of antioxidant enzymes and accumulation of molecules that effectively scavenge ROS. If ROS production exceeds the plant’s capacity to detoxify it, deleterious effects at the cellular level may occur. The balance between the production and the scavenging of activated oxygen is thus crucial to plant growth maintenance and overall environmental stress tolerance. However, alterations in plant metabolism may lead to reduced crop yield and quality, directly or indirectly by exposing susceptible plants to stress factors. Secondary metabolites are constitutively synthesized and are of interest for human health and nutrition, especially because some of them are major sources of biologically active substances. However, they are also well known as plant defence molecules and their concentrations can be influenced by abiotic stresses such as ozone. Increased accumulation of plant secondary metabolites in leaves of forest trees in response to ozone exposure has been reported in several studies, while the changes on crop plants composition and nutritional quality need to be further studied and discussed to guide our efforts to select ozone-tolerant crops in an attempt to provide a secure food supply for a developing world.

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