Ethylene and Lipoxygenase In Relation to Afterripening of Dormant NC-13 Peanut Seeds1,2

Abstract

Following harvest, peanuts are usually subjected to a period of storage. During storage biochemical changes are known to occur. The objectives of this study were to determine the changes and relationship in ethylene production, germination, and lipoxygenase (LG) activity during cold storage of dormant NC-13 peanut seeds. Two seed lots (SL) were used: one grown in Oklahoma (SL80) and the other grown in N. Carolina (SL81). SL80 and SL81 were stored at 2 to 5 C for 193 and 242 days, respectively. Samples were taken at about 28-day intervals for determination of germination, ethylene production, and LG activity. Seeds of two and three maturities were tested for SL80 and SL81, respectively. As afterripening of stored seeds proceeded, ethylene production gradually increased, with the maximum at 48 hours of germination. Germination showed a concomitant gradual increase. Lipoxygenase activity of both seedlots was less for mature than for immature seeds and showed a sharp increase during storage at 2 to 5 C, particularly for immature seeds. After heat-treatment to break dormancy of sublots from SL81, there was a progessive increase in ethylene production and germination, but most notably for mature seeds. In contrast to ethylene production and germination, after heat-treatment LG activity declined. Linear correlation coefficient (r) values between ethylene production and germination were highly significant for mature seeds from SL80 at 48 and 72 hours of germination, but only at 72 hours for immature seeds. For SL81 as for SL80, significant positive correlations were found between ethylene production and germination. However, correlations between LG activity and the other variables were not significant except for mature seeds from SL81. Significant positive correlations for both ethylene production and germination with LG activity also existed for these seeds. But after heat-treatment these correlations no longer occurred. The data indicate that the metabolic processes related to ethylene production and germination are occurring simultaneously with those of LG activity. The possibility that metabolites from LG activity serve as substrates for ethylene production can not be precluded.

Differences in Development of Oleic and Linoleic Acid in High- and Normal-Oleic Virginia and Runner-Type Peanuts

“…The indeterminate flowering trait of the peanut is responsible for the range of pod maturities and seed sizes observed at peanut harvest. In normal peanut development, the seed rapidly accumulates carbohydrate and near mid-maturity, lipid accumulation becomes the dominant storage process (Ketring et al, 1982, Sanders et al, 1982. The study reported here describes the development of the O/L ratio in NO and HO seed for both virginia-and runner-type cultivars as a function of individual seed fresh weight in order to document the physiological expression of the HO trait over the course of peanut seed growth.…”

EFFECT OF HIGH AIR AND SOIL TEMPERATURE ON YIELD AND SOME YIELD COMPONENTS OF PEANUT (Arachis hypogaea L.)

“…Peanut varieties differ in their sensitivity to high temperatures. Ketring et al (1982) indicated that temperature plays a critical role in the growth and development of peanut plants and it appears that optima are different depending on the phase (reproductive or vegetative) of development.…”

“…Tai and Hammons (1978) and Wynne and Isleib (1978) reported that the evaluation of peanut cultivars for genotype x environment interaction on yield and yield components seems to indicate only minor effects of genotype x location and genotype x year interactions, but there were relatively large genotype and genotype x location x year interactions. Since temperature is critical for peanut plant growth and development, attempts have been made to determine temperature requirements of peanut cultivars at different stages of their development (Ketring et al, 1982).…”

“…The pod weight reduction per plant was calculated 12.3 g plant -1 (16%) in 2017. Ketring et al (1982) indicated that temperature plays a critical role in the growth and development of peanut plants and it appears that optima are different depending on the phase (reproductive or vegetative) of development. The optimum soil temperature for individual pod growth rate is between 31 o C and 33 o C (Ono et al, 1974 andDreyer et al, 1981).…”

“…The peanut plants produced many flowers but, only 15-20% of flowers produce mature pods (Lim and Hamdan, 1984). Ketring et al (1982) indicated that temperature plays a critical role in the growth and development of peanut plants and it appears that optima are different depending on the phase (reproductive or vegetative) of development. Prasad et al (2000) reported that peanut plants are susceptible to both high air and soil temperature due to their aerial flowering and subterranean fruiting habit, respectively.…”