Nitric oxide (NO) is an important signalling molecule employed by plants to control many physiological aspects. This review summarizes that crosstalk between NO/H2O2/Ca2+ signalling pathways that drive pollen tube for sexual reproduction in flowering plants. NO is produced in seeds by both enzymatic and non-enzymatic sources that control many physiological aspects of seeds. The interplay of NO and Reactive oxygen species are likely important players in hormonal crosstalk controlling seed germination and dormancy. Mechanism of seed germination and dormancy is mainly regulated by plant hormones like Abscisic acid (ABA) and Gibberellic acid (GA). Based on mode of action of NO with reference to triggering the germination of crop seeds under abiotic stress condition it is infer that there is a linkage between NO and plant growth regulator production. NO cross-talk with reactive oxygen species (ROS) during abiotic stress condition, modulate the light and hormone depended developmental process in the early stage of plant development. NO action to enhancing abiotic stress tolerance by improving antioxidant enzymes and protection against oxidative damage in many crops are discussed in detail.

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Curry leaf, Murraya koenigii (L.) Sprengel is mainly propagated through seeds, which have poor storage potential due to recalcitrant in nature. The present study evaluated the suitable storage method for prolonging the viability of the seed. The results showed that the shelf life of curry leaf seed was extended upto 40 days by storing in 300 gauge polythene bags at 10°C. However, the seeds stored under environmental condition maintained the viability upto 10 days only. Also, the seeds stored along with moist media have not better way for extending the shelf life when compared with seed stored at 10°C. The maximum seedling vigour and least electrical conductivity and free sugars were found in the seeds stored at 10°C. Seed chlorophyll, total phenols, protein and α-amylase activity were reduced during seed storage and the reduction was lower when the seeds were stored at 10°C. The damage in cell structures was also found in the desiccated seeds that the results showed that the curry leaf seeds can be stored upto 40 days in 300 gauge polythene bag at 10°C.

The importance of availability of quality seed of high-yielding varieties in achieving food security has been recognized globally. The chapter presents an overview of the activities and requirements of seed production system globally, with an emphasis on quality, and highlights the linkages between variety development and seed production programmes. The seed development in angiosperm through the process of fertilization has been briefly touched and understanding the processes underlying pollination, fertilization, seed development, and maturation, which are vital for production of quality seed, has been highlighted. System of variety development and release, maintenance of variety purity during seed multiplication, and their importance have been enumerated to benefit those associated with any seed programme. Seed quality parameters including physical and genetic purity, physiological quality, seed vigour, and health, along with factors determining seed quality, have been presented in a holistic manner. Regulatory mechanism for seed quality assurance including steps in seed certification, seed testing and various field and seed standards has been outlined comparing the Indian system with other major international systems working globally. Procedures for seed health testing and application of advanced molecular marker technologies for varietal identity, genetic purity of seed and detection of seed-borne pathogens, which are becoming increasingly relevant in the present seed scenario, have been discussed. Fundamentals of seed processing for quality upgradation, and improvement of seed quality through enhancement technologies, have been explained. The chapter presents an overview of the importance of seed quality, its indicators, regulations, systems of development of varieties and their maintenance and use of modern tools and techniques for assurance and enhancement of seed quality.

A field experiment was conducted to study the stigma receptivity and method of pollination in improving pod and seed quality in glory lily at Botanical Garden, Tamil Nadu Agricultural University, Coimbatore. Results revealed that, dusting of foreign pollen on the stigma (pollination) one day after anthesis resulted in higher pod set of 88 per cent, while pollination on the day of anthesis resulted in 80 per cent and bud pollination one day before anthesis resulted in 68 per cent pod set. These results clearly revealed that the stigma of glory lily flower was receptive even before anthesis and continued to attain the maximum receptivity one day post anthesis. Among different pollination methods, hand pollination was the best as revealed through the superiority in terms of pod and seed yield parameters such as maximum pod set (96 %), higher pod length (8.4 cm), pod girth (6.8 cm) and weight of pod (4.92 g) and higher seed weight per pod (3.04 g), number of seeds per pod (74.0) and shelling percentage (61.78 %) accompanied with better seed quality parameters such as higher germination (54 %) and vigour index (1252) of the seeds in glory lily.