eChapters

To start with let the self-incompatibility be defined.

• Self-incompatibility is the mechanism by which plant can prevent selffertilization.
• Self-incompatibility is defined as inability of a plant producing functional gamete to achieve self-fertilization.
• Self-incompatibility is a genetically based mechanism which controls mating within angiosperm species by imposing a ‘barrier’ between pollination and fertilization.
• The term incompatibility is used to describe the failure of pollen tube to penetrate the full length of the style and to effect fertilization.

Semen is admixture of secretions of testes containing spermatozoa and accessory sex glands. Spermatozoa are formed in the seminiferous tubules of the testes. The tubules contain a complex series of developing germ cells that ultimately form the male gametes. The spermatozoa are unique type of cells containing nucleus (head portion) and a tail. The acrosome is a double walled structure situated between the plasma membrane and the anterior portion of the sperm head and neck connects the sperm head with its tail.

Semen collection is the most important component of any frozen semen production programme as a high quality end product is not possible unless the raw material is of excellent quality. Therefore, all care should be taken to collect semen aseptically with the aim to harvest the best quality neat semen for processing. The person collecting semen should understand bull’s behaviour and should be friendly with him. Professional bull management results in increasing sperm output and enhancing productive life of the bulls. One must know potentials and limitations of the reproductive capacity of bulls. A highly professional and dedicated team of bull handlers and semen collectors is required for this purpose. The persons involved in bull management should be familiar with bull’s sexual behavior and male reproductive physiology. Preferably a veterinarian should collect semen.

Semen collection in bulls and buffalo bulls

Semen collection from domestic animals is an art and skilled job to get maximum quantity and quality of an ejaculate. Ejaculation of semen in a male is a complex process and consists of several events sexual arousal, courtship, erection, penile protrusion, mounting, intromission, ejaculation, orgasm like reaction and dismounting. Ejaculation is the result of neuro-muscular stimulation that starts in the vas differentia and accessory sex glands. The semen ejaculation is finally brought about by the rhythmical contractions of penile musculature and urethra. The muscular contractions proceed progressively in waves, forcing the semen out of the external urethral orifice. To get good quality semen, the bulls must undergo all the related events of ejaculation. The semen collectors should have knowledge of inhibitory and stimulatory factors for the act of ejaculation in male domestic animals. The stimulatory factors are:

• Semen cryopreservation – It is the process of preserving the semen in a suitable medium at an ultra-low temperature which reduces spermatozoa metabolism with the least production of metabolic waste products of sperm cells to prolong their life span. • Every fall of 100 C temperature decreases the metabolic rate of spermatozoa to half. Principle of various components involved in cryopreservation 1. Low temperature • Reduce metabolism (negligible) and least metabolic waste product • Decrease solute solubility leads to increased viscosity and physical resistance • Reduce motility • Prolong life span 2. Protection from cold shock and cryoinjury • When sperm cells are subjected to a reduction in temperature during the freezing process, there are: • Sperm membrane damages and lead to leakage of intracellular components like enzymes, ATP, K+ , cholesterol, lipoproteins etc. • Irreversible abnormality in motility pattern (bending of sperm tail)

Semen dilution/ extension is done to meet the following objectives

1.    To preserve the fertilizing potential of semen for a long period of time

2.    To increase the number of services per ejaculate. Ideally approximately 500 cows/ buffaloes can be inseminated from diluted/ extended semen of  a single ejaculate.

3.    Extenders provide the spermatozoa with a medium in which they are able to remain viable and fertile for a prolonged time period.

In order to be an ideal extender, it should be able to provide conducive environment to prolong sperm survival and modify the sperm structure to prepare them for freezing through the following properties:

1.    It should be isotonic with blood and should maintain this during preservation.

The idea behind semen dilution is to extend its volume without affecting its fertility so that many females can be bred from an ejaculate. The basic components of semen extender are Tris buffer, fructose, glycerol, egg yolk and antibiotics.

Semen evaluation alone should not be interpreted as the sole indicator of the fertility of bulls but it will provide significant information of the sexual apparatus. After receipt of the semen sample in the laboratory, it is kept in a hot water bath at 350C until the evaluation is complete. One has to prevent cold shock to the living sperm cells during the evaluation process. All the glassware and other items coming directly or indirectly in contact with the sperm cells should be sterilized properly and kept ready in a thermostatically controlled cabinet at body temperature. Sudden changes in exposure of semen to cold or hot temperature results in higher dead spermatozoa or sperm agglutination. Semen should not be exposed to sunlight, wind, chemicals, smoke, vibration and water. A single laboratory test is not sufficient to assess the semen quality and semen should be examined within a shortest possible time after ejaculation as mentioned below (Table 9.1).

Microscopic examination 

A phase contract microscope with biotherm (37o C) is necessary for correct evaluation of semen because the refractive index of spermatozoa differs slightly from that of the surrounding medium. The ordinary bright field microscope will not provide sufficient contrast between the spermatozoa and the medium. Under phase contrast microscope, the object will appear dark on a bright background. This is achieved by reducing the light passing through the object by half a wavelength compared to the light passing through the medium. The eyepiece has a magnifying capacity of 10X while the objectives have 10, 40 and 100X. This will provide the microscope the magnifications of 100, 400 and 1000. The lenses and eyepiece should be kept clean by wiping with tissue paper and distilled water. Xylol can also be used to remove greasy material. The microscope has to be kept in one place and covered with Perspex cover when not in use to avoid dust accumulation. Personnel familiar with the operation of a particular microscope alone should be allowed to handle the microscope, since lot of differences exist between different makes of microscopes. 

Good quality semen is more acidic than semen with lower sperm concentration. In contrast, bacterial contaminated semen and semen with more dead spermatozoa evolve ammonia that will increase pH of semen. In orchitis, seminal vesiculitis and epididymitis the pH of semen will be alkaline due to presence of pus. In azoospermic or necrozoospermic semen, the pH may be neutral or alkaline. pH variation may be due to change in season/climate and frequency of successive ejaculates. Depending on the concentration and activity of spermatozoa, the pH of semen varies. The narrow range pH (BDH) paper are more convenient in routine work. The first change in color is matched with color on the cover of booklet. Use of BDH capillary set is time consuming whereas digital pH meters are also being used. The normal pH range is depicted in Table 11.1.

Semen is needed to be extended with a suitable medium and cryopreserved without affecting its survivability and fertility for the purpose of inseminating female artificially. Qualities of Ideal Extenders • Semen extender is a nutrient media which provide energy to spermatozoa, protection from osmotic shock, thermal shock and various metabolic wastes for prolonging the life span of sperm cell with maintaining the acceptable fertilizing capacity. A semen extender should have qualities to protect spermatozoa during dilution and cryopreservation. These qualities may be : 1. Preserving sperm cell integrity (membrane, cellular, mitochondrial and acrosomal integrity etc) 2. Maintenance of osmotic pressure (isotonic; 280-300 mOsm/l) similar to seminal plasma 3. Providing nutritive elements as energy source for sperm metabolism (aerobic & anaerobic metabolism)

• After equilibration, a pre-freeze evaluation of semen is done. Pre-freeze motility should be more than 70% at 370 C which makes the semen eligible for freezing. Semen Packaging • Semen is packaged in suitable container like pellets, glass ampoules, tupol (polyethene tubes) and semen straws. • In the Ampoule method, semen is packed in glass ampoules and stored in LN2 . Here labeling and handling is easier with less chances of contamination. But more storage space, more time taking to thaw and the use of glass catheter for insemination make their the use less convenient. • In Pellet methods, diluted semen is frozen by pouring it into the holes (0.1, 0.2 ml) made on dry ice (Solid CO2 at 790 c) and these pellets (frozen semen balls) are stored in LN2 . Here glycerolization is not needed as well as process is also quick but labeling is difficult and the chances to get contaminated are more. Handling pellets for insemination is also difficult (breakage or getting stuck to forceps during retrieval).

Objectives
• To introduce the concept of seminars and conferences.
• To impart knowledge on organizing seminars and conferences.
• To highlight the necessity of such platforms for intellectual and professional exchange.
• To provide insights into the qualities of effective seminars and conferences.
Introduction
Seminars and conferences are platforms for intellectual exchange that have grown significantly in scope and purpose over time. Originally restricted to academic settings, these forums have become indispensable in professional environments. Traditionally, they allowed students and researchers to present their findings through oral or written reports. However, in the modern era, characterized by unprecedented advancements in science and technology, the need for structured intellectual engagement has increased.
These gatherings offer an excellent opportunity for individuals to think collectively, solve complex problems, and plan strategically. They providethe necessary environment for brainstorming and collaboration, ensuring th  efficient use of both human and material resources. In this century of rapid technological evolution and global connect ivity, seminars and conferences serve as crucial tools for learning, networking, and driving innovation.

INTRODUCTION

“An insect is like an old-fashion soldier: it does what it is ordered to do, and when it has no orders it does nothing” (a citation from Wright, 1963). The orders are very often given as chemical signals that induce certain behaviour or change the course of development in the insect. Chemical communication appears to be the primary mode of information transfer in insects. These chemicals are able to modify the behaviour of a perceiving organism at sub-micro/nanogram levels and are known as semiochemicals. The term is derived from the Greek Word Simeone, meaning a mark of a signal. These behaviour modifying chemicals are divided into two broad categories.

Introduction

Spatial variation structure of soil properties is a key input for digital soil mapping and generally determined through geostatistical techniques (Webster and Oliver 2007). In geostatistics, spatial variation is expressed by semivariogram ?(h) , which measures the average dissimilarity between data separated by a vector h. It is generally computed as half of the average squared difference between the components of data pairs:

Senna (Cassia angustifolia Vahl.) popularly called as ‘Sonamukhi’ is widely used medicinal herb in Ayurveda, Unani and also in Allopathic system of medicine. It is well known for its purgative activity (Bentley and Trimen, 1999). The plant is known by various names in common conversation likes Sennai, Sona, Sonamukhi, Sennamukki, Sonpar, etc.  Presently, there is a growing demand of senna  dry leaves and processed products in the national as well as in international markets. In recent years, its cultivation has gained momentum in arid and semi- arid parts of Rajasthan and Gujarat due to its diversified adaptability. It has also been widely adopted by the farmers because of its low cost of cultivation with yield stability. Its main characteristics viz., drought hardy, perenniality, non-palatability to animals has also attracted the farmers for its popularity. Moreover, the senna crop is eco-friendly as it can be utilized for wasteland, sand dune stabilization and desert development (Bohra and Sankhla, 1997; Tripathi, 1999).

Botany: Senna, Cassia angustifola belonging to the family Leguminosae is a perennial 1-2 m height undershrub. The stem is erect, smooth, and pale green to light brown with long spreading ascending branches. Leaves are compound with four to eight pairs of leaflets. The full grown leaflets are bluish-green to palegreen in colour and emit a characteristic fetid smell when crushed. The flowers are small and yellow and axillary arranged racemes. The pods are broadly oblong about 5-8 cm long and 2-3 cm broad, green in beginning and change to greenish-brown to dark brown on maturity. Each pod has 5 to 7 ovate, compressed, smooth, dark-brown seeds.

Varieties : KKM - 1, Anand Late Selection, ALFT-2 and Sona

Soil and climate: In Tamil Nadu, it is grown in sandy or sandy loam or laterite soils. It is a hardy warm weather crop grown under rainfed and irrigated conditions. Senna is also cultivated successfully on black cotton soils. It has a great tolerance to high soil salinity, however, shedding of some lower leaves often occurs. The soil pH suited for cultivation is 7.0-8.5. But, the most suitable to sandy loam to loam soils which are more friable and well drained.

Organ of vision (Eye)

The vision is by far the most used of the five senses and is one of the primary means that is used to gather information from the surroundings. The organ of vision or the bulb of the eye is contained in the bony socket called the orbit in the skull. The bulb of the eye (eyeball) is embedded in the fat of the orbit. Associated with the eyeball within the orbit are certain accessory structures viz. the muscles, fasciae, eyelids, conjunctiva and lacrimal apparatus.

Orbit

The orbit is the cavity or socket in the skull wherein the eyeball and its accessory structures (appendages) are situated. The orbit is continuous caudally with the temporal fossa. The axis of the orbit which is usually considered as running between the optic foramen and the middle of the socket is directed rostrad, laterad and dorsad. The medial wall of the orbit is formed by the frontal, lacrimal and the presphenoid (wing) bones of the skull. It is concave and smooth. The medial wall in its rostral part presents a fossa that is called the lacrimal fossa which accommodates the lacrimal sac along with the lacrimal gland. Caudal to the lacrimal fossa is a small depression for the attachment of obliquus ventralis muscle. The dorsal wall of the orbit is formed by the frontal and partly by the lacrimal bone. The supraorbital foramen, an opening of the canal perforating the root of the zygomatic process, is situated in the dorsal wall of the orbit. The ventral wall is slightly rough and is formed by the zygomatic bone, the zygomatic process of the temporal bone, the zygomatic process of the frontal bone and the part of the maxilla bone. The lateral wall (rim) of the orbit is formed by the zygomatic process of temporal bone and the temporal process of the zygomatic bone. Several foramina and/ or fissures for the passage of the vessels and nerves are located in the walls of the orbit. These include the optic, alar, oval, supraorbital, ethmoidal, lacrimal, maxillary, sphenopalatine, and the orbitorotundum foramen.

Detection of sensations allow the body to be aware of changes (or stimuli) that occur in the environment or inside the body. These senses permit the central nervous system to produce reactions for the stimuli and maintain body homeostasis. Somatic senses (“soma” means body) detect touch, pain , pressure, temperature, and tension on the skin and in internal organs. Special senses detect the sensations of taste, smell, hearing, equilibrium, and sight, only in special sense organs in the head region. All senses are detected by sensory receptors, and after integration and processing being done in the central nervous system, motor nerves produce a response.

Fishes use their sense organs to detect their bodies and their environment. Sense organs include the eyes, the lateral lines, the nostrils, the olfactory organs and the taste organs. Each of these sense organs is equipped with sensory nerve endings. Most fish possess highly developed sense organs to detect smell, sight, hearing, taste, touch, temperature, etc.

27.1 Olfaction in Fishes

27.1.1 Introduction