Flowers are borne on reproductive axes, either as solitary structures or on inflorescences, which can be unbranched or variously branched (Figure 5.1). In a determinate inflorescence, the inflorescence apex is terminated by a flower, whereas in an indeterminate inflorescence it maintains growth until the apical meristem becomes exhausted. Each flower is often subtended by one or two modified leaf-like sterile bracts borne on the inflorescence axis, though bracts are entirely absent from some species. Some species also possess one or more leaf-like bracteoles on the flower axis. At the onset of flowering, the shoot apical meristem undergoes structural modification that transforms it from a vegetative apex to a reproductive apex.

The seed represents the dispersal unit of a plant. Seeds are dispersed from the flower either as separate units or enclosed inside a fruit. Each seed develops from a fertilized ovule. Fruits can develop from various structures, including a single ovary (simple fruits, found in the majority of angiosperms), a flower with multiple free carpels (aggregate fruits, e.g. in Ranunculus), a single carpel (e.g. the monocarpellate pod of the legume family Fabaceae) or even from an entire inflorescence (e.g. in pineapple, Ananas comosus).

Leaves are determinate lateral organs that are usually dorsiventrally flattened and lack a growing tip. Foliage leaves are green; they are typically borne on stems above ground level because they require sunlight for photosynthesis. Angiosperm leaves consist of a sheathing leaf base that clasps the stem at the node and a distal zone that extends away from the stem to capture light effectively. In eudicots and magnoliids, the sheathing lower zone is often reduced or sometimes absent and the distal zone forms the bulk of the leaf, consisting of a petiole and an elliptical blade (lamina) with net-like (reticulate) venation (Figure 4.1). The margins of the lamina can be smooth, lobed or toothed.

Stems are axes that are typically cylindrical, elongated and branching, though many modifications can occur in different species. Shoot apical meristems are present at the tips of all the stem branches; lateral branches are initiated from buds that are borne in the axils of leaves. Stems are most commonly aerial, though some stems occur below ground. Aerial stems are often green and photosynthetic during early growth but subsequently turn brown following radial stem thickening. Some underground stems are modified into storage organs such as corms or rhizomes that allow them to survive a harsh winter or dry season below ground.

Roots are typically branching cylindrical structures that develop underground to facilitate extraction of moisture and nutrients from the soil, often in association with hyphal networks of soil-dwelling fungi. In contrast, epiphytes and epiliths, which grow entirely above the ground, often develop aerial roots that absorb moisture from their environment. In vascular plants, the root apex is a growing tip where both the root cap and the primary root tissues are produced. Lateral roots are initiated some distance from the root apex, by cell divisions in the pericycle, among differentiated cells that have retained meristematic capacity.

Plants are essentially modular organisms; each individual plant consists of distinct but connected organs. In their turn, the organs are composed of cells, which are mostly grouped into tissues. Vegetative organs support photosynthesis and plant growth, and reproductive organs enable sexual reproduction. In seed plants, the primary vegetative organs are the root, stem and leaf (Figure 1.1). Roots and stems have well-defined growing points at their apices, but the leaves are determinate lateral organs that stop growing when they reach a particular size and shape. When a seed germinates, the seed coat (testa) is ruptured and the embryonic structures emerge from opposite poles of the embryo: a seedling root (radicle) grows downwards from the root apex and a seedling axis (hypocotyl) bears the first leaves (cotyledons) and the shoot apex, which ultimately develops new foliage leaves.

There are two fundamentally distinct conservation strategies, in situ and ex situ that are distinguished based on whether the target taxa are conserved where they are found or are sampled and moved to a secondary location to be conserved. Within the two strategies there are a range of in situ and ex situ techniques, each of which aims to maximize the range of plant genetic diversity maintained. There are advantages and disadvantages associated with each strategy and technique. The two strategies for conservation, in situ and ex situ, complement each other and the mixture of strategies and techniques employed to conserve a target taxon will vary from taxon to taxon depending on its characteristics and the resources available to conserve that taxon.

This chapter provides a historical perspective on the development of community-based conservation and how approaches are grounded in changes that not only occurred in conservation practice but also in agriculture and rural development. This is achieved by looking at some of the pivotal changes in thinking and ideas that have taken place relatively recently in conservation practice and in agriculture and rural development. How these changes have been reinforced by the rapid rise of social movements lobbying for greater farmer and local community control over resources and food sovereignty is also reviewed in the context of its impact on conservation thinking. The chapter also highlights some key principles and guidance when considering collaboration and partnership with smallholder farmers, indigenous and community groups and provides an overview of approaches, tools and methods that are considered useful for facilitating community-based conservation and sustainable use of plant genetic resources.

The conservation of plant species where they naturally occur involves the planning, design, establishment, management and monitoring of viable populations of the target taxa to be conserved. It will involve the writing of a management plan as a guide to management implementation primarily based on knowledge of the target taxon’s ecology and its relationship to the biotic and abiotic environment. Regular monitoring of key populations within the reserve will ascertain whether the management plan is effective in conserving genetic diversity. Often, however, the conservationist will have to make a compromise between the objectives of the reserve and the desires of other users. The material conserved within the reserve should be made readily available to the various user groups.

Knowledge regarding gene bank accessions characters facilitates the identification of the most promising for future use. Sampling of accessions from a cultigen available at a gene bank may be based on diversity and variability analysis relying on characterization or evaluation data, DNA markers, or both. Core subsets may aid selection by guiding users to genetic differences. Evaluation results must be shared promptly and widely worldwide, so germplasm users can request them for further utilization in plant breeding or research on plant genetic resources. This chapter relates therefore to gathering accurate and precise evaluation of diverse accessions in well-designed trials. Such knowledge is essential for identifying the most relevant accessions for further use. This information needs to be shared widely and quickly with users to achieve a maximum impact because any germplasm user should be aware of the potential of gene bank accessions in order to fully exploit such plant genetic resources.This chapter also illustrates the need for an objective assessment of gene bank accessions, deals with sampling of core subsets for evaluation of gene bank accessions, explains the principles of experimental design for trials of gene bank accessions and provides basic knowledge regarding trial data analysis.