**1. Introduction**

It is a known fact that environmental pollution constitutes an important problem in Turkey as well as in the rest of the world. Rapid industrialization and population growth have caused pollution in the atmosphere, pedosphere, and hydrosphere.

Therefore, it is seen that countries pay particular attention to pollution-related studies and health problems caused by pollution and allocate high amounts of resources to deal with the problem.

**2. Effects of heavy metals, nanoparticles, and nanotubes on plant**

*Plant Phenology and An Assessment of the Effects Regarding Heavy Metals, Nanoparticles…*

metals and metalloids on the environment and in terms of their toxicity or

about 60 years. An element with a density of more than 7 g/cm<sup>3</sup>

The term heavy metal has been used by scientists with various definitions for

1995 with a density of 6 g/cm<sup>3</sup> with a metallic property was classified as heavy metal in 1964. Some scientists have classified heavy metals according to their atomic weights, atomic numbers, other chemical properties, and toxic properties. In biological terms, the term heavy metal is generally used for possible contamination of

Heavy metals are released into the atmosphere, pedosphere, and hydrosphere every day due to human activities besides natural causes, such as volcanic activities. Flying ashes from the chimneys of cement plants and thermal power plants; the use of heavy metal paint; the smoke emitted by motor vehicles as well as their plasticbased parts such as brake pads, garbage, and waste sludge incineration plants; and the release of industrial wastes, such as pesticides, fertilizers, paper, batteries, products, etc. are among the main causes of heavy metal pollution [5–7].

The discharge of heavy metal-containing particles released from the factory and

Heavy metals have toxic effects for living organisms at certain concentrations. However, certain critical concentrations of some heavy metals are necessary for normal and healthy plant growth. Therefore, heavy metals are classified as essential elements and nonessential elements according to their participation in life processes. Cobalt (Co), copper (Cu), manganese (Mn), molybdenum (Mo), iron (Fe), nickel (Ni), and zinc (Zn) are heavy metals necessary for the growth and vitality of plants and are considered essential elements. Heavy metals such as barium (Ba), cadmium (Cd), mercury (Hg), antimony (Sb), lead (Pb), and chromium (Cr) are not essential for plants and other living organisms and are called nonessential

Essential elements are found as a cofactor in many enzyme systems and as a structural component in biological processes in living organisms. For example, copper is an essential element for normal plant growth at certain concentrations. Copper is an essential cofactor for many metalloproteins in plants and plays a role in photosynthetic electron transport, mitochondrial respiration, cell wall metabolisms,

High concentrations of copper (depending on plant species) show toxicity in plants although it is an essential element. Lead is not an essential element and shows toxic properties for plants. The presence of excess copper and lead in the environ-

These heavy metals result in lipid peroxidation [15], degradation of cell and thylakoid membrane structure, and a decrease in chlorophyll amount due to the change in the chloroplast structure and thus chlorosis as a result of the oxidative damage they caused [16]. Heavy metals bind to sulfhydryl (-SH) groups of proteins and inhibit enzyme activity [17] and cause oxidative DNA damage [18, 19], chro-

More than 30 base lesions were characterized by DNA exposure to reactive

mosomal abnormalities [20], and lack of other essential elements [21–24].

oxygen species [25]. On the DNA, reactive oxygen species can cause

and hormone signal transduction pathways [12, 13].

ment negatively affects phenological development in plants [14].

plant chimneys onto agricultural lands, their dissolution in the soil by rain or irrigation, or the irrigation of agricultural land mixed with industrial wastewater leads to various diseases in crops grown on such lands and damages the agricultural

, in 1992 with a density greater than 5 g/cm<sup>3</sup>

, in 1987 with a

, and in

**phenological development**

*DOI: http://dx.doi.org/10.5772/intechopen.91904*

density of more than 4 g/cm<sup>3</sup>

ecotoxicity [4].

economy [8–10].

elements [11].

**5**

Heavy metals show toxic effects at certain concentrations for living organisms. However, low concentrations of some heavy metals are essential for normal and healthy plant growth. Furthermore, heavy metals and nanoparticles are causes of concern because they can penetrate into different parts and cells of plants at different rates, and by this way, they enter the food chain and reach the living beings.

There are about 22,000 bryophyte species and 20,000 algae species; however, vascular plants are the dominant plant group in the world with 255,000 species. Land plants, which perform their life cycles completely in the terrestrial environment, are mainly composed of bryophytes and vascular plants. Furthermore, at least a thin film of water is required for fertilization in all taxa except seed plants. Even in the two primitive genera seed plants, cycad and gingko, fertilization is a result of free-swimming spermatozoids released into the liquid medium in the archegonium chamber [1–3].

One of the most important features of vascular plants is the presence of buds at the ends of the trunk and side branches in the gymnosperms and generally in the angiosperms. The bud is an apical meristem coated with protective bud scales. Meristem is the region of cells to which new cells, tissues, and organs are added and has the potential for active cell division and contributes to plant growth. Therefore, despite the limited growth potential in animals, plant growth is limitless due to the presence of apical meristem. However, the development of plant parts, such as leaves, flowers, and fruits, is limited to their shapes and is genetically predetermined [1]. In short, when evaluated from a phenological point of view, plant parts do not show any further growth independent of the time they remain on the plant after completing their development.

Cell development and differentiation take place as the changes occurring in protoplast; for example with the fusion occurring in vacuoles to grow, via structures such as mitochondria, plastids and the golgi body, endoplasmic reticulum, microtubules, and microfilaments in cytoplasm. Cell walls differentiate and increase in thickness due to structural and environmental effects, and they may become permeable. Moreover, the walls may integrate with the lignin, which increases tensile forces. Tissues formed by the differentiation of apical meristem include parenchyma, collenchyma, sclerenchyma, and primary xylem and primary phloem, in which the pith and cortex are formed [1, 2].

Phenological stages are divided into eight possible principal stages: [1] bud development, [2] leaf development, [3] shoot/branch development, [4] inflorescence emergence, [5] flowering, [6] fruit development, [7] fruit maturity, and [8] senescence and the beginning of dormancy [3]. Secondary parts and secondary metabolites occur in the plant during the phenological cycle [1]. Genotype and environmental factors are involved in the emergence of seconder metabolites. In this case, based on the amount of soil, water, and air pollution in the environment in which the plant grows, various deteriorations may occur as a result of morphological and physiological changes whose effects on the plant can be seen with the naked eye or observed only through microscopic examinations. In this chapter, general information about heavy metal and nanoparticles is given, and the effects of heavy metals and nanoparticles on the seedlings of runner bean (*Phaseolus coccinea*), chickpea (*Cicer arietinum*), and artichoke (*Cynara scolymus*) species, which are of economic importance, were examined morphologically and anatomically.

*Plant Phenology and An Assessment of the Effects Regarding Heavy Metals, Nanoparticles… DOI: http://dx.doi.org/10.5772/intechopen.91904*
