(pp. 3-11)
Plant Growth and Development in Two Types of Abnormal Peanut (Arachis hypogaea L.) Seedlings
R. J. Lovey,* O.T. Del Longo, and J.A Argüello
ABSTRACT:
The effects of two seedling abnormalities: 1) curved hypocotyl forming a loop (CH) and 2) primary root split from the tip (PRS) on several growth variables and timing of bloom onset of peanut (Arachis hypogaea L.) plants were investigated. During early ontogeny plants developed from abnormal seedlings were shorter and had shorter internodes than those developing from normal seedlings.
Total biomass was lower in plants from CH seedlings only. Internode formation, leaf production and root length at the end of the assessment period were not affected by either abnormality. Neither of the abnormalities affected timing of bloom onset. Seedlings with CH and PRS abnormalities appear to be capable of recovery during growth and to bloom normally. Further studies are necessary to determine how different types of peanut seedling abnormalities affect the yield of the crop under field conditions.
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(pp. 12-19)
A Comparison of Stereomicroscope and Image Analysis for Quantifying Fruit Traits
C.Mix, F. X. Picó* and N. J. Ouborg
ABSTRACT:
Two methods, ocular measurements using a stereomicroscope and computerized image analysis, were compared to assess the usefulness of image analysis as an efficient and precise method to measure variation in fruit traits, such as fruit length. Individual fruits from nine plant species differing in size, shape, and the existence of dispersal-related structures were measured repeatedly with both methods.
Results showed significant between method differences in fruit length. Image analysis tended to overestimate fruit length, although differences between the two methods were very small. Both stereomicroscope and image analysis discriminated fruits of different sizes, whatever their shape, and no bias due to size was found in any case. However, low (though significant) correlations were found for measurements of elongated fruits with a tailed pappus obtained by both methods. Overall, we conclude that image analysis represents a good method to accurately estimate variation in fruit traits. The advantages of using image analysis are (1) the high amount of fruit parameters obtained with one single measurement, (2) the minimization of human errors, (3) the reduction of time needed to obtain large data sets concerning fruit trait variability, and (4) the possibility to estimate variability in traits of fruits with complicated shapes.
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(pp. 20-32)
Relation between Respiration, Dehydrogenase Activity and Germination Capacity of Artificially Aged Common Wheat
Giovanni Dinelli, Carla Lucchese
ABSTRACT:
The identification of new markers for germination capacity, activities and electrophoretic patterns of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) isoforms were evaluated in artificially aged common wheat (Triticum aestivum L.) seed samples with different germination levels. The physiological determinations were carried out on seeds imbibed under aerobic (moist paper) and anaerobic (submersion in water) conditions.
Under both imbibition conditions wheat seeds with low germination capacity (AA2 and AA3 samples) showed reduced water uptake, respiration,ADHand LDHactivities, and high electrical conductivity of seed leachate. The seed characterized by intermediate germination capacity (AA1 sample) showed respiration quotient values 1.5 and 1.7 times higher than control seeds, respectively, after 6 and 12 h imbibition under aerobic conditions.At 24 h imbibition under aerobic or anaerobic conditions, the isoform profiles of LDH were the same for all seed samples. Patterns of ADH isoforms extracted from seeds imbibed under aerobic conditions showed no difference among aged seed samples. Imbibition under anaerobic conditions showed two clearly visible additional bands in the ADH electrophoretic pattern of high germination capacity seeds. These additional bands were not observed in the aged seed samples. Anaerobic conditions seem to amplify differences in ADH isoform pattern, that might be used as an indicator of high germination capacity in wheat seeds.
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(pp. 35-40)
Germination of Perennial Ryegrass Florets with Caryopses Less than One-third the Length of the Palea
Sabry Elias*, Adriel Garay, and Dale Brown
ABSTRACT:
It has been long debated among seed analysts whether to define caryopses (dry, indehiscent one-seeded fruit, as in grasses) with some degree of endosperm development as pure seed or inert matter. This study was conducted to evaluate the germinability of perennial ryegrass seed (Lolium perenne L.) that contain caryopses less than one-third the length of the palea and compare them with seed that contain caryopses at least one-third the length of the palea.
Random samples from forty seed lots representing two cultivars harvested in 1999, 2000, and 2001 were examined. Florets with caryopses having some degree of endosperm development were separated from each sample and germinated following the AOSA Rules for Testing Seeds. One hundred single florets with caryopses one-third the length of the palea or more from each sample were also germinated as control checks. The germination of seeds with caryopses less than one-third the length of the palea was 0.33%, compared to 92% for seeds with more than one-third the length of the palea. The results suggested that florets with caryopses less than one-third the length of the palea should not be classified as pure seed, but should be classified as inert matter. If the AOSA Rules were changed, it would result in uniformity between the AOSA and ISTA Rules regarding this standard. In addition, including such seed in the inert matter of a sample would result in increasing the germination percentage.
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(pp. 41-44)
Effect of Seed Pre-treatment on Germination of Two Surface Types of Dialium guineense
Idu MacDonald and Oghogho Omoruyi
ABSTRACT:
Two types of seed surface, smooth and wrinkled, in the seed lot of Dialium guineense Willd, were nicked, immersed in hot water at 100 and 50 °C, soaked in HNO3 and H2SO4 and mechanically scarified to improve germination under both light and dark conditions. Smooth seeds treated with H2SO4 (5 min) and in boiling water at 100 °C (5 min) resulted in high germination, 74% and 70%, respectively. However, among the wrinkled seeds, only the boiling water treatment at 100 °C (5 min) resulted in 50% germination. Generally, seeds tested under light conditions were higher in germination than those in the darkness.
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(pp. 45-49)
Homobrassinolide Effects on Germination and %-amylase Activity in Wheat Seeds
S. Hayat, Q.Fariduddin and A.Ahmad*
ABSTRACT:
Healthy grains of Triticum aestivum (L) cv.HD-2204 were imbibed in 10-6, 10-8 or 10-10 M aqueous solution of 28-homobrassinolide (HBR) for 4, 8 or 12 hours. Treated seeds were then transferred to petriplates, lined with water soaked filter paper, for germination. It was observed, after 96 hours, that
percent germination and the activity of α-amylase were enhanced irrespective of HBR concentration and soaking duration. The maximum values for germination and α-amylase activity were recorded in the grains soaked in 10-10 M of HBR for 4 hours, which were 60% and about four times more than the water soaked control, respectively. It was closely followed by the next higher concentration (10-8 M) of the hormone.
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