INTRODUCTION

It is important to understand the structure and workings of plants if you are to grow them to their full potential. Knowledge about a plant’s life cycle indicates when it should be sown or planted, grown on and harvested, with each of the different categories named, defined and discussed, together with what treatments the plant may require to get the best from them, this knowledge includes their durability, economic use, and decorative or structural value.

Knowing about a plant’s external and internal structure and how they work is very useful for propagation, this leads on to such decisions as the type of material to use related to the time of year or the plant’s ability to produce adventitious roots on a wide range of different parts. A selection of species within a plant genus can have very different propagation and maintenance requirements. Also this information has a role to play in solving physiological problems that may occur with plants, especially those related to nutritional imbalances.

However, please note that there is still much to learn about the internal workings of plants and research is still ongoing. This greater and developing understanding will be useful in the future to help improve plant growth and yields to feed an ever-growing population. To aid in the gaining of this knowledge you will need to first develop a basic understanding of how plants grow, and hopefully this chapter will give you this introductory understanding.

INTRODUCTION

Within this section the direction is provided to start influencing the growing or display conditions for plants, that provide the best or quickest results. Leading on from the foundations, the opportunities are outlined and discussed for adjusting our thinking of how to obtain the maximum benefit from our present knowledge level and build on this to meet our objectives, whatever they may be.

One of the most pleasing aspects of gardening is the reward of new plants that are free apart from a little time and effort. Propagating plants vegetatively provides a plethora of methods, with the background reasons for the selected methods being discussed, together with the alternatives on offer. Technical language is fully explained and images are provided to enhance understanding of the practical aspects.

The whole subject of designing plants leads on from home propagational techniques into a world filled with a new language and some fears about the unknown, and worries as to the pathway of genetic modification being a one-way street or dead end to some species.

Shaping plants, as a topic, is always high on the agenda when plant people meet or undertake garden visits. The discussion runs from the ‘only prune to shape, once in a lifetime’ through to the ‘cut it to the ground, once a week, if not more often’ view, and everything in between. However, often the reasons and the methods that can be used are unknown or have been forgotten over time. Whereas, newer methods or techniques, such as the Chelsea chop, are being adjusted or renamed for modern times.

INTRODUCTION

Horticulturists throughout the ages have striven for plants that suit their needs: be they flower colour, odour, fruit size, shape, uniform harvest or resistance to pests and diseases. This chapter explains the biological processes that produce these characteristics (genetics and the inheritance of characteristics) and goes someway to explore the methods used by horticulturists in achieving a ‘designed’ plant. The techniques and morals of genetic engineering are explored in some detail, as this is an emotive and relatively modern technique of designing plants that is often cited in the media, commonly with some bias. It is important that you, as a student of horticulture, are informed of this technique and are able to make decisions of the validity of its use, for yourself, based upon a sound technical knowledge and understanding of the processes involved.

Genetics is, among other things, the study of the inheritance of characteristics. Characteristics may be observable, such as flower colour, shape or odour, or they may be ‘hidden’, such as the plant’s abilities of disease resistance or resilience to dry conditions, either naturally or in times of stress.

The way these characteristics are passed from one generation to another is by means of genes (it is, however, important to point out that the environment also has an effect on a plant’s characteristics although we will focus mainly on the genes’ role). Genes are lengths of DNA (deoxyribonucleic acid), a long string-like chemical that chromosomes are made from, and are located within the nucleus of cells.

Introduction

The gravity and magnetic methods measure spatial variations in the Earth’s gravity and magnetic fields (Fig. 3.1). Changes in gravity are caused by variations in rock density and those in the magnetic field by variations in rock magnetism, which is mostly controlled by a physical property called magnetic susceptibility. Gravity and magnetic surveys are relatively inexpensive and are widely used for the direct detection of several different types of mineral deposits and for pseudo-geological mapping.

Magnetic measurements made from the air, known as aeromagnetics, are virtually ubiquitous in mineral exploration for wide-area regional surveying, for detailed mapping at prospect scale and for target detection. In areas where exposure is poor, aeromagnetics has become an indispensable component of exploration programmes. Gravity measurements are also used for regional and prospect-scale mapping but, historically, measurements of sufficient accuracy and resolution for mineral exploration could only be made on the ground. The development of airborne gravity systems, known as aerogravity, with precision suitable for mineral targeting, means that aerogravity in mineral exploration is likely to become as common as aeromagnetics.

Geophysical methods respond to differences in the physical properties of rocks. Figure 1.1 is a schematic illustration of a geophysical survey. Over the area of interest, instruments are deployed in the field to measure variations in a physical parameter associated with variations in a physical property of the subsurface. The measurements are used to infer the geology of the survey area. Of particular significance is the ability of geophysical methods to make these inferences from a distance, and, for some methods, without contact with the ground, meaning that geophysics is a form of remote sensing (sensu lato). Surveys may be conducted on the ground, in the air or in-ground (downhole). Information about the geology can be obtained at scales ranging from the size of a geological province down to that of an individual drillhole.

Geophysics is an integral part of most mineral exploration programmes, both greenfields and brownfields, and is increasingly used during the mining of orebodies. It is widely used because it can map large areas quickly and cost effectively, delineate subtle physical variations in the geology that might otherwise not be observed by field geological investigations and detect occurrences of a wide variety of mineral deposits.

INTRODUCTION

In the wild, the majority of higher plants reproduce by means of seeds. However, in the garden this is often not desirable, or may not be possible and other means must be used to obtain new plants. Therefore vegetative methods have been developed where a section of the parent plant is selected and roots are established so it can live independently.

A variety of different methods can be used to propagate plants vegetatively. These include softwood and hardwood cuttings, root cuttings, leaf cuttings, division, layering and a number of specialised techniques, such as grafting, budding and reproduction from structures such as bulbs and corms. The first section (Basic principles) is concerned with the physiological principles underlying the regeneration of new plants by vegetative propagation, with the second section (Practical techniques) focusing on the practicalities of the various procedures. Some techniques are very simple and success is guaranteed, while others require patience, skill, equipment and perfect timing. Micropropagation has become an important method for the regeneration of large numbers of plants by vegetative means and more details are given in the text below. Other methods are outlined with the time of year or age of the material highlighted. This allows a more informed view for the propagator to select a more suitable, potentially easier, method to be chosen with the aim of maximum success as the result. The environmental options available are also discussed, together with the required equipment, for all technical levels.

In this chapter we discuss several concepts that are useful for the analysis of time series in business and economics. Examples of such concepts are autoregressive moving average models, autocorrelation functions, parameter estimation, diagnostic measures, model selection, and forecasting. In this chapter these concepts are treated within the context of non-trending, non-seasonal, and linear univariate time series with constant variance. Although none of the five features highlighted in Chapter 2 will be dealt with explicitly, the above concepts are generally useful and often can be adapted to accommodate the apparent empirical features of the time series at hand.

The technical detail in this chapter is kept at a moderate level. The main focus is on explaining why the concepts are useful, how the relevant methods can be implemented in practice, and how the outcomes can be interpreted. It is not our intention to downplay the importance of formal asymptotic results for the techniques reviewed here, but our primary goal is to keep the discussion accessible, having in mind the actual use of these techniques in empirical time series modeling. We recommend the interested reader to consult more advanced time series textbooks such as Anderson (1971), Fuller (1976), Abraham and Ledolter (1983), Granger and Newbold (1986), Box et al. (1994), and Hamilton (1994). Also, there are many other concepts in time series analysis that we do not treat in detail here. The content of the present chapter merely reflects what should be a useful basis for modeling real-world time series, such as those discussed in the previous chapter.

INTRODUCTION

The ‘feel good factor’ of good light levels is well known to humans with the pleasing emotional response to sunshine and the longer days of summer being welcomed after a long, dark winter.

However, green plants (all those with leaves or stems that contain chlorophyll) are completely dependent on light for many aspects of their growth and development. In particular, light energy is required to fuel the process of photosynthesis, which results in the production of carbohydrates and, subsequently, leads to all of the other organic components of plants. Light is also an important source of information for plants, giving them the ability to sense their light environment and, in many cases, also their seasonal environment.

This chapter describes how plants use light under different environmental conditions to ensure growth is continued to successfully complete their life cycles and set seed to provide future generations. The chapter also considers how gardeners can manage light most efficiently in the context of the garden, especially as climate change is likely to lead to altered seasonal light levels. The interrelationship of light with temperature and water availability leads on to future management and the opportunities presented with the balance between light and shade. Shade perception and plant adaptations to shade are also introduced to provide a greater understanding of this common, but somewhat challenging, environment.

INTRODUCTION

Why is it important for the reader to have a knowledge and understanding of flowers, fruits and seeds? First, the vast majority of the food we eat is produced from plants grown from seeds: including large-scale farming and vegetable production as well as ‘grow your own’ crops.

Having an understanding of flower parts and the types of inflorescence can help you to identify a plant. This chapter covers flower parts and structure, including the various types of inflorescence.

The function of flowers is to produce fruit and seed to perpetuate the species. The flower facilitates the pollination and fertilisation of the ovules that ensures the production of seed. Fertilisation results in the production of fruit, which ensures the survival and spread of the seed.

With the recent loss of pollinating insects, including bees, it is important to have a good understanding of pollination and fertilisation to ensure a good crop of fruit is produced. Factors affecting pollination and fertilisation and how the grower can improve these are discussed in this chapter.

Seeds also have the ability to survive very difficult climatic conditions that would kill many plants, thus the plant can survive over winter and grow again in the spring. A good understanding of seed germination requirements, overcoming dormancy and ensuring the correct conditions for growth helps to ensure a good crop. The germination process is explained along with the types of dormancy and how these control when the seed will germinate. Methods of breaking seed dormancy are also explained.

Finally, how to propagate plants from seed both indoors and outdoors and the various sowing techniques are covered.