Relationships Between Seed Respiration During Imbibition and Subsequent Seedling Growth in Zea mays L.

Abstract

Summnary. Corn (Zea wiiays L.) seed respiration rates during the first 30 hours of germination were compared with seedling growth 3 to 5 days after planting. Significant positive correlations were observed between rates of 02 uptake during imbibition and later stages of germination and seedling growth. Glutamic acid decarboxylase activity also was positively correlated with seedling growth. The highly significant correlations between respiratory quotients and seedling growth were negative.Seed metabolism during the initial hours of germination is evidently related somehow to seedling growth rates several days later. Whether this relationship is due to the dependence of synthetic processes and growth on respiratory energy, the fact that high respiration rates reflect high levels of metabolic activity, or to some other cause, remains to be determined.Many observations relating respiration to plant growth have been reported, but respiration-rates usually have been measured on activelyv rowing tissues. Thus, it cannot be unambiguously determined whether differences in respiration are a cause or a result of differences in growth. In this report, differences in respiration of germinating corn seeds are shown to precede differences in seedling growth and not to result from that growth.Throneberry and Smith (16) reported that loss of viability in corn seemed c!osely related to respiratory failure. The activities of malic and alcohol dehydrogenases and cytochrome oxidase were highly correlated with germination percentage. Indeed, the activity of the dehydrogenase enzymes provides the basis for the tetrazolium test for seed viabilitv (6). Frequently, however, the activity or lack of activity of a particular enzyme, or even group of enzymes, cannot be directly related to seed viability. In many cases, the activity of a certain enzyme mnay survive seed death (10). Conversely, some enzymes fail to show activity even in viable seed. Throneberry an(d Smith (16) found that different seed lots deviated from the regression line relating enzyme activ.ty to seed viability, depending on the enzym1ie assayed. The present investigation was predicated on the assumption that respiratory rates, depending on and reflecting the coordinated activity of many enzymes, might be more highly correlated with physiological characteristics of seeds such as viability or grovth than wvould be the activity of any one individual enizymlle. (18,19) and chilling injury in lima beans (20). Glutamic acid decarboxylase activity (GADA) is also related to seed germination (7) and has been used as an assay for seed storability (4, 5).In this investigation, we measured the respiration and GADA of samples of corn seeds having dif ferent levels of deterioration resulting from various longterm storage conditions. Respiration was measured between 2 and 30 hours after the start of imbibition as 02 uptake and as CO. evolution and compared with several indices of seed vigor and seedling growth. Materials and MethodsCorn seeds (Zea mavs L.) were stored for 4 years at...

Metabolic Changes in Partially Dormant Wheat Seeds during Storage

“…With some exceptions (2, 4) respiratory measurements have been used to establish relative vigor in seeds (20,21). Present data agree with previous reports in that those seeds which produced the fastest growing seedlings also had the highest respiratory rate (20) and that the rate of 02 uptake declined only after germinability had declined (2).…”

Ethanol and Acetaldehyde in Imbibing Soybean Seeds in Relation to Deterioration

“…2B). We suggest that submerging the seeds created anaerobic conditions under which pyruvate accumulated and was converted to acetaldehyde and ethanol as suggesed by others (6,11,20,24). Likewise, when HR seeds were imbibed in 1 mm sodium azide for 2 or 4 h, there was a 2-fold increase in acetaldehyde and a 3-fold increase in ethanol relative to the water-imbibed controls (Table III).…”

“…y-irradiation, mechanical damage, desiccation, heat, and adverse storage conditions, leads to changes in respiratory metabolism, such as lower rates of 02 uptake, higher respiratory quotients, or both (24). High respiratory quotients in germinating seeds might be explained in terms of an imbalance between the tricarboxylic acid cycle ETC1 and the glycolytic pathway in which the products of glycolysis, such as pyruvate, accumulate and are decarboxylated (11,20,24). During early imbibition of Phaseolus mungo seeds, activation of mitochondria is delayed relative to that of glycolysis (12).…”

Single-seed oxygen consumption measurements and population-based threshold models link respiration and germination rates under diverse conditions

“…The physiological and cellular processes required to repair damage accumulated in the dry state and to subsequently transcribe RNAs, translate proteins and support embryo growth required for completion of germination depend upon the production of ATP and reductants via oxidative mitochondrial respiration (Bewley et al, 2013). It has long been known that seed quality, as indicated in particular by the speed and percentage of germination in a seed population, is associated with respiratory capacity (Woodstock and Grabe, 1967), and some tests of seed vigour and viability (e.g. the tetrazolium staining test and ethanol production) are based upon this relationship (Woodstock, 1973;Rutzke et al, 2008;Buckley and Huang, 2011;Kodde et al, 2012).…”