Showing papers on "Seedling published in 1983"

Seed Germination in a Seasonal Tropical Forest in Panama: A Community Study

Abstract: Seed germination in the seasonal tropical forest on Barro Colorado Island, Panama, was studied at the community level to (1) determine the seasonal timing of germination of the community, (2) identify primary selective factors controlling timing of germination, (3) determine the relative importance of dormancy vs. timing of seed dispersal as mechanisms controlling timing of germination, (4) examine inter— and intraspecific components of variance in length of dormancy, and (5) identify major seed germination syndromes. Three community—level measures of seedling emergence indicated that there was a unimodal community peak in germination within the first 2 mo of the 8—mo—long rainy season. Of the °185 dicot, mostly woody, species germinating each year, the median time of emergence of 75% of the species occurred within the 1st 3 mo. There was a unimodal peak in germination in pioneer tree species, lianas, canopy trees, wind— and animal—dispersed species, and seedlings with and without persistent seed reserves. In contrast, there was no distinct peak period of emergence in understory species and shade—tolerant tree species. Initial seedling height of species emerging sequentially throughout the rainy season did not increase. The early emergence of most species, including three—fourths of the 35 species fruiting in the late rainy season, indicated that the early rainy season was the optimal time to emerge. Maximizing the length of the first growing season was not an important factor selecting for early emergence, because later—emerging species did not compensate for the shorter growing season by being larger at germination or by having seed reserves for rapid growth. Seedling—seedling competition is a primary biotic factor selecting for early emergence in pioneer species growing in the intensely competitive light—gap habitat. In shaded understory habitats, where competition among seedlings is much less intense, understory and shade—tolerant tree species emerged throughout the rainy season. Mean length of dormancy (MLD),the time between sowing and germination, of 157 woody dicot species on Barro Colorado Island ranged from 2 to 370 d. In over half the species, MLD exceeded 4 wk; hence, delays in germination are common. The season in which seeds were dispersed and the dispersal mechanism explained small but significant portions of the variance in MLD among species; life form explained none; but differences among three germination syndromes explained two—thirds of this variance. In the delayed—rainy syndrome (18% of all species) seeds were dispersed in the rainy season but were dormant until the beginning of the next rainy season, 4—8 mo later. Dormancy is the primary mechanism controlling time of germination. In the delayed—rainy syndrome and the intermediate—dry syndrome which follows, the length of the dormant period decreased as the interval between seed dispersal and the beginning of the rainy season decreased. In the intermediate—dry syndrome (42% of all species) seeds were dispersed during the during the dry season and remained dormant until the beginning of the rainy season. Seeds are primarily dispersed 1—2 mo before the beginning of the rainy season, which reduces the number of false germination cues encountered and decreases the length of time seeds are exposed to postdispersal predation while dormancy prevents germination during dry season rains. In the rapid—rainy syndrome (40% of all species) seeds were dispersed in the rainy season and germinated during, but not early in, that season. Dormancy has been replaced entirely by timing of dispersal as a mechanism controlling time of germination. Half of these species germinated in <2 wk, the rest in 2—16 wk.

The effects of size of opening in vegetation and litter cover on seedling establishment of goldenrods (Solidago spp.)

Abstract: We investigated the effects of size of opening in the vegetation and litter cover on seedling establishment of two species of goldenrods (Solidago spp.) in an abandoned field in southwestern Michigan, U.S.A. Seeds of S. canadensis and S. juncea were sown into clipped plots, ranging from 0 cm (control, unclipped) to 100 cm in diameter, with and without litter. Seedling emergence, survival and growth were followed for one year. Soil moisture was not significantly different among the opening sizes, but, within a size, tended to be lower when litter was removed. Light intensity at the soil surface was positively related to opening size early in the growing season, but later in the growing season reached a maximum in intermediate-sized openings and then leveled off.

Relationships between seed weight, ash content and seedling growth in twenty‐four species of compositae

Abstract: SUMMARY The relationship between seed weight, embryo weight, ash content and maximum size attained by seedlings dependent on their own food reserves was investigated in 24 species of Compositae. The fraction of total seed weight contributed by the seed coat increased with seed weight from 15 % in Erigeron canadensis to 61 % in Tragopogon pratensis. Seedling weight was proportional to embryo weight raised to the power of 2/3. That is, the larger the embryo the less carbon it assimilated per unit weight of embryo. The relative growth rate of the seedlings during the first 3 weeks was inversely proportional to In embryo weight. The root weight ratios of the seedlings were inversely proportional to In embryo weight. The ash content of the seeds was negatively correlated with their weight but absolute mineral content per seed was directly proportional to maximum seedling size attained, regardless of seed size. It is postulated that the relatively larger seed coats of big seeds are a defence against increased risk of predation. The ash contents and root weight ratios of the seedlings suggest that the growth of small seedlings is limited by soil nutrients and that of large seedlings by light.

Ash content and seedling growth in twenty-four species of compositae

Abstract: The relationship between seed weight, embryo weight, ash content and maximum size attained by seedlings dependent on their own food reserves was investigated in 24 species of Compositae. The fraction of total seed weight contributed by the seed coat increased with seed weight from 15 % in Erigeron canadensis to 61 % in Tragopogon pratensis. Seedling weight was proportional to embryo weight raised to the power of 2. That is, the larger the embryo the less carbon it assimilated per unit weight of embryo. The relative growth rate of the seedlings during the first 3 weeks was inversely proportional to ln embryo weight. The root weight ratios of the seedlings were inversely proportional to ln embryo weight. The ash content of the seeds was negatively correlated with their weight but absolute mineral content per seed was directly proportional to maximum seedling size attained, regardless of seed size. It is postulated that the relatively larger seed coats of big seeds are a defence against increased risk of predation. The ash contents and root weight ratios of the seedlings suggest that the growth of small seedlings is limited by soil nutrients and that of large seedlings by light.

Seed Predation and Seedling Mortality in the Recruitment of a Shrub, Haplopappus venetus (Asteraceae), along a Climatic Gradient

Abstract: Haplopappus venetus is a characteristic shrub of the coastal sage scrub of southern California. Its relative frequency decreases rapidly and significantly from the coast to the central valleys of southern California. Insect damage to developing flowers and seeds is high (35-61%). Experimental exclusion of predispersal flower and seed predators caused a significant increase in the number of viable seeds released because of: (I) a decrease in insect-caused abortion of flower heads (1 1%), (2) an increase in pollination success (19%), and (3) a decrease in damage to developing seeds (104%). A significant and proportionate increase in the number of seedlings established at sites over the climatic gradient from coast to inland valleys followed the exclusion of seed predators. In the inland area, however. extremely high mortality among established seedlings prevented recruitment of juveniles. Mortality of established adult plants, in contrast, was higher at the coast than inland (41 vs. 31%, respectively), suggesting that the geographic difference in the abundance of juveniles would persist. These results differ from those for a parallel experiment on H. squarrosus in which juvenile recruitment was determined by differential predispersal seed predation along the gradient and was not altered by differential mortality among seedlings. Consequently, I conclude that insect seed predation can be the critical factor limiting population recruitment, as in the case of H. squarrosus, but it need not be, as in the case of H. venetus. In the latter case, seedling mortality patterns, superimposed on seed predation, were critical to an explanation of plant recruitment and occurrence over the climatic gradient.

Allelopathic effects of juglone on germination and growth of several herbaceous and woody species

Abstract: Laboratory experiments were conducted to determine juglone sensitivity of 16 species (Trifolium incarnatum, Coronilla varia, Vicia villosa, Lespedeza stipulacea, L. cuneata, Acer ginnala, Caragana arbor-escens, Elaegnus angustifolia, E. umbellata, Lonicera maackii, Quercus alba, Fraxinus americana, Liriodendron tulipifera, Alnus glutinosa, Pinus strobus, andP. sylvestris) being considered for mixed plantings withJugions nigra (black walnut). All species were sensitive to juglone, but seed germination and radicle elongation were less affected than shoot elongation and dry weight accumulation. Seed germination and radicle elongation were affected by juglone in 6 and 11 species, respectively, mainly by the higher concentrations (10−3 M and 10−4 M). Shoot elongation and dry weight accumulation of all species were affected by juglone; many species were sensitive to concentrations as low as 10−6 M. Seedlings of all species were severely wilted and eventually killed by 10−3 M juglone, and most were chlorotic and severely retarded by 10−4 M juglone. Seedlings inhibited by 10−6 M and 10−5 M juglone did not showany visible signs of injury. Based on the effects on seedling shoot elongation and dry weight accumulation, the five species found to be most sensitive to juglone were:Lonicera maackii, Lespedeza cuneata, Trifolium incarnatum, Alnus glutinosa, and Elaeagnus umbellata.

Herb Cover Effects on Tree Seedling Patterns in a Mature Hemlock-Hardwood Forest

Abstract: The role of herbs in affecting tree seedling patterns was investigated in an old—growth hemlock—hardwood forest in Cathedral State Park, West Virginia. Herb species cover, tree seedling density, and overhead foliage were sampled along with midsummer soil pH, soil moisture, and light intensity in 20 selected herb patches and 440 30 x 30 cm plots. Analyses of the patch data showed significant correlations of seedlings of major tree species: Prunus serotina, Acer rubrum, Tsuga canadensis, and Betula spp., with leading herb species (Dennstaedtia, Mitchella, Lycopodium, and Oxalis). Each tree species had few seedlings in some herb species patches, but was independent of or concentrated in other patches. Herb species were spatially related to other herb species, but showed little correspondence to soil pH, soil moisture, and light intensity patterns. Analyses of plot samples supported each of the above results. In addition, total tree seedling density was inversely correlated with total herb cover, but neither ...

Sunflowers (Helianthus annuus) are allelopathic to weeds.

Abstract: Laboratory, greenhouse, and field studies were conducted to determine the allelopathic potential of sunflower (Helianthus annuus L.) cultivars to suppress weed germination and growth. Germination of wild mustard [Brassica kaber (DC.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler] seeds at 25 C in undiluted aqueous extracts of sunflower leaf tissue was inhibited 75%, but was stimulated by up to 150% at 10- and 100-fold dilutions. Stem-tissue extracts at all concentrations stimulated wild mustard seed germination. The germination response of other weed species varied with the sunflower cultivar and concentration of tissue extract. In sand culture, leachates of dried sunflower leaf and stem tissue inhibited broadleaf - weed seedling growth, but had little or no effect on the growth of grass weeds. Sunflower root exudates inhibited seedling growth, but were less effective than leaf and stem tissue leachates. Germination of weed seeds was unaffected by root exudates. Over a 5 -yr period, weed density and percent ground cover increased less in field plots of sunflower than in control plots.

Photooxidative destruction of chloroplasts and its consequences for cytosolic enzyme levels and plant development.

Abstract: Mustard (Sinapis alba L.) seedlings were grown in the presence of herbicides (Difunon, Norflurazon) which inhibit carotenoid synthesis without affecting development, in darkness or in continuous far-red light. In strong white light (12,000 lx) the cotyledons of the herbicide-treated seedlings did not contain normal chloroplasts, but only small chlorophyll-free rudiments whose internal structure had almost disappeared. The plastid marker enzyme NADP-dependent glyceraldehyde-3-phosphate dehydrogenase was almost lacking. Plastid ribosomes and ribosomal RNAs were no longer detectable nor could synthesis of mature plastidal ribosomal RNAs be detected. Cytosolic ribosomes and rRNAs were not affected. Plastid DNA was apparently still intact as shown by restriction analysis. The appearance of marker enzymes of glyoxisomes, mitochondria and cytosol was not impaired while the level of marker enzymes of peroxisomes was drastically lowered. Accumulation of anthocyanin in mustard cotyledons was normal after a short, transient delay. Levels of representative enzymes of flavonoid biogenesis (phenylalanine ammonia-lyase, chalcone synthase) were somewhat increased rather than inhibited in the cotyledons of herbicide-treated, white-light-grown seedlings. The growth rate of hypocotyl and cotyledons was inhibited to the same extent in the herbicide-treated, white-light-grown seedling, although light inhibits growth of hypocotyls and promotes growth of cotyledons. Analysis of the data shows that photomorphogenesis of a herbicide-treated, white-light-grown seedling is normal, and is thus independent of plastid gene expression However, a ‘factor’ which coacts multiplicatively with phytochrome in determining the growth rate of the organs seems to originate from the plastids. Biogenesis of anthocyanin and synthesis of major enzymes of the flavonoid pathway are not affected adversely by a photooxidative elimination of plastid gene expression.

Influence of Cultivation Regime Upon Buried Weed Seeds in Arable Cropping Systems

Abstract: (1) The effects of cultivation on the number of seeds of different species in arable land were investigated at four sites over several years. Soil cores were obtained from uncultivated and ploughed plots, and the seed content determined by germinating the seeds and counting and identifying the emerged seedlings. (2) Distribution of seeds was not uniform in the soil profile, and fluctuated annually on ploughed plots. Seed decline, although not markedly different between treatments, was more rapid in ploughed soil. The rate of seed decline at different depths was similar for both uncultivated and ploughed plots. Successful germination alone could not account for the rate of seed decline reported,4indicating that losses from other causes were substantial. (3) A considerable number of species were recorded in the seed bank (23-30), but only a few (3-4) comprised the majority. A number of species present in the seed bank of uncultivated soil were absent from the seedling flora.

A neighbourhood approach to self-thinning.

Abstract: The fate of individual plants of Helianthus annuus was monitored in populations sown at a density of 650 seeds m-2. Ninety six percent of the seeds germinated but only fifty two percent of the seedlings survived to the end of the experiment due to self-thinning. Whilst the seedlings emerged over only four days the cotyledons then took up to eight days to emerge from the seed case and open fully. The survival of individuals depended primarily on cotyledon-opening time but plants which occupied very small areas (<900 mm2) at germination were also less likely to survice. The increased likelihood of mortality amongst the late germinating individuals was probably as a result of shade from older, larger neighbours. It is suggested that one-sided interference for light during self-thinning will increase the importance of early establishment relative to neighbour effects in determining the survival of plants except at very high levels of crowding. The complex of environmental and genetic factors acting to maximise the growth rate of the very young seedling relative to its neighbours will clearly play an important part in determining the position of a plant in the size hierarchy of a population.

Studies on copper and cobalt tolerance in three closely related taxa within the genus Silene L. (Caryophyllaceae) from Zaire

Abstract: Experiments were carried out on the tolerance to and uptake of copper and cobalt by three members of a phylogenetic series of taxa within the genusSilene from Zaire which were reputed to represent a progression of increasing adaptation to metalliferous soils. Plants studied were the widespread and presumably non-tolerantSilene burchelli var.angustifolia (B), a more tolerant variant of this taxon (E) designated an ecotype, and the metallophyteS. cobalticola (C). Studies on the effects of both metals, singly and in combination, on seed germination, seedling and plant performance and yield, and metal uptake from soil cultures, confirmed in general the sequence B

Fruit size variation and its effects on germination and seedling growth in Xanthium strumarium

Abstract: Fruits of Xanthium strumarium L. from a population in southwestern Ontario exhibited an eightfold range in size. The effects of fruit size on seed size, germination, and seedling growth were investigated. Correlations between fruit size and seed size were strongly positive. In general, germination percentage and germination rate were both correlated positively with fruit size, although germination rate appeared to level off for the largest fruits. Cotyledon area and primary root length of newly emerged seedlings also were positively correlated with fruit size, although both variables and especially primary root length showed smaller increases over larger fruit sizes. The weights of newly emerged seedlings were highly positively correlated with fruit size. However, this relationship was not maintained for older seedlings. Weights of 15- and 30-day-old seedlings were constant over the majority of fruit sizes. This trend resulted from a negative correlation between seedling growth rate and fruit size which c...

Influence of seed size on germination and early development of loblolly pine (Pinustaeda L.) germinants

Abstract: Seed size was examined as a possible explanation for variation in the size of containerized loblolly pine (Pinustaeda L.) seedlings. Under laboratory conditions of minimal environmental stress, larger seed were found to germinate more quickly and produce a larger germinant after 28 days of growth. In a similar experiment conducted under greenhouse growing conditions, large seed produced the largest seedlings. Size differences among seedlings in both experiments resulted from differences in the rate of germination unique to each seed size class. Consequently, seedling size and possibly uniformity of growth were considered to be a function of germination patterns which were strongly influenced by seed size and weight.

Demographic patterns of seedling establishment and growth of native graminoids in an alaskan tundra disturbance

Abstract: SUMMARY (1) Presence or absence of buried seed was the major factor governing natural revegetation of a bulldozed disturbance in Alaskan tussock tundra. The viable buried seed pool contained 97% Eriophorum vaginatum and Carex bigelowii seed and was restricted to organic soil horizons. Consequently, disturbed organic soils reached a final seedling density of 250 seedlings m-2 (primarily Carex and Eriophorum) 4 years after disturbance, whereas mineral soils which were colonized by current seed deposition had only 30 seedlings m-2, including many grasses. (2) Fertilization enhanced the growth of grass and 2-4-year-old Carex seedlings fourto ten-fold but had no significant effect upon Eriophorum seedling growth. Growth was not significantly affected by presence of already established seedlings and did not differ between substrates, except for grasses which grew more rapidly on mineral than organic soils. (3) Seedling mortality during the first 2 years after germination was low (43% in Eriophorum, 27% in grass, and 13% in Carex) and did not differ between organic and mineral substrates. Mortality of 1- and 2-year-old seedlings was concentrated during the growing season, but mortality of larger seedlings was primarily a consequence of winter grazing. Mortality was increased by fertilization. (4) The greater vascular plant biomass and cover on organic than mineral soils was due primarily to recruitment from the buried seed pool. The increase in biomass and cover with fertilization was a consequence of a stimulation of growth by grass and Carex. (5) We recommend stockpiling and re-utilizing soil organic matter, supplemented under certain conditions by fertilization and sowing of seeds, as a mechanism of enhancing natural community restoration of arctic tussock tundra following man-made disturbances.

The localization, metabolism and biological activity of gibberellins in maturing and germinating seeds of Pisum sativum cv. Progress No. 9

Abstract: Gibberellin A20 (GA20), GA29 and GA29-catabolite were quantified in cotyledons, embryonic axes, and testas of Pisum sativum cv. Progress No. 9 throughout the final stages of seed maturation and during germination. Stable isotope-labelled GAs were used as internal standards in conjunction with combined gas chromatography-mass spectrometry. Gibberellin A20 and GA29 were mainly located in the cotyledons of maturing seeds, and GA29-catabolite was predominantly located in the testa. Stable isotope- and radio-labelled GA20 and GA29 were fed to both intact seeds developing in vivo, and to isolated seed parts cultured in vitro. The combined results of in-vivo and in-vitro feeds indicated that GA20 is metabolised to GA29 in the cotyledons, that GA29 is transported from the cotyledons to the testa, and that GA29 is metabolised to GA29-catabolite in the testa. Although the metabolism of GA20 in the cotyledons and of GA29 in the testa has been shown definitively, the mobility of GA29 has not yet been demonstrated directly. During seed desiccation and germination GA29-catabolite and products arising from it are transferred from the testa into the embryo. There is no evidence of a physiological function for GA29-catabolite in germination or early seedling growth. Use of a growth retardant indicates that seedling growth, but not germination, is dependent on de-novo GA biosynthesis.

The differential establishment of seedlings from chasmogamous and cleistogamous flowers in natural populations of the grass Danthonia spicata (L.) Beauv.

Abstract: The grass Danthonia spicata produces dimorphic seeds from chasmogamous and cleistogamous flowers. The seed remains attached to seedlings so one can identify the reproductive origin of seedlings. The proportion of chasmogamous and cleistogamous seedlings becoming established varies widely between populations. The types of seedlings becoming established was generally consistent from year to year and correlated with the proportion of flower types produced. Mown populations showed especially high levels of cleistogamous seedling establishment. Germination and seedling survival were experimentally investigated. Chasmogamous and cleistogamous seeds had different germination behaviors. Cleistogamous seedlings had higher survival rates than chasmogamous seedlings.

The Development of Enzymes During Germination and Seedling Growth in Nigerian Sorghum

Abstract: The levels of enzymes responsible for the enzymic modification of sorghum endosperm have been followed during germination and seedling growth. Sorghum β-glucanase was shown to be inactive towards barley β-glucan. Gibberellic acid does not appear to control the levels of α-amylase. In contrast to barley, the synthesis of this enzyme occurs in the embryo but it subsequently acts on the starch granules in the endosperm. Limit dextrinase, on the other hand appears to be present in the endosperm as a zymogen. Proteases were also examined during germination and seedling growth. Amino acid-releasing enzymes develop in the embryo and are absent from the endosperm, whereas endoproteases can be detected in the embryo and to a greater extent in the endosperm. Amylolytic attack on endosperm starch in sorghum is very extensive during the early stages of grain growth. The significance of these results to the malting properties of sorghum is discussed.

Growth and survival of current-year seedlings of Polygonum cuspidatum at the upper distribution limit on Mt. Fuji.

Abstract: Seedling establishment of Polygonum cuspidatum Sieb. et Zucc. colonizing in a volcanic gravel area at 1,400 m and 2,500 m altitude on Mt. Fuji was compared. At the upper altitudinal limit (2,500 m) the average dry weight of seedlings at the end of the first growing season after germination was 24 per cent of that at 1,400 m. The proportion of seedlings, which survived the winter, was significantly (P<0.005) higher at 1,400 m than at 2,500 m. Seedlings in the range of 0-10 mg DW could not survive winter at any altitude. The survival rate increased with increasing seedling dry weight up to 100 per cent in seedlings with sizes more than 40 mg DW at 1,400 m. Seedlings from 2,500 m with sizes below 2 mg DW did not form perennation buds and were found to die before winter. Smaller seedlings in the range of 2-20 mg DW, even if they had buds, did not survive in the-15°C freezing resistance experiment. Larger seedlings (40-100 mg DW), which were grown in pots at 1,400 m and transferred to 2,500 m, survived winter those like as at 1,400 m. The difference in mean seedling dry weight between at 1,400 m and at 2,500 m was attributable to the difference in the length of the growing season and not to a different relative growth rate. It appears that there is a critical amount of annual dry-matter production necessary for full freezing resistance and winter survival capacity and therefore for successful seedling establishment.

Influence of Cucurbitacin Content in Cotyledons of Cucurbitaceae Cultivars upon Feeding Behavior of Diabroticina Beetles (Coleoptera: Chrysomelidae)

Abstract: Nineteen species and 46 cultivars of Cucurbita, Cucumis , and Citrullus were analyzed for seedling cucurbitacin (Cuc) content by Diabrotica feeding on thin-layer chromatography extracts. Seedlings, leaves, and fruits were monitored for damage in the field by Diabroticina. Beetle damage to the mature leaf and fruit was unrelated to seedling Cuc content or feeding damage. The information is of value in selecting resistant varieties of Cucurbitaceae cultivars for integrated pest management programs. A new analytical procedure for cucurbitacins using high-pressure liquid chromatography is described.

Effects of ammonium and nitrate on growth and nitrogen uptake by mycorrhizal Douglas-fir seedlings

Abstract: In a greenhouse pot study, mycorrhizal and non-mycorrhizal Douglas-fir seedling were grown in a forest soil amended with clays and ammonium or nitrate fertilizer. Mycorrhizal seedlings grew taller, increased root and shoot dry weight more, and accumulated more nitrogen and phosphorus than non-mycorrhizal seedlings. Mycorrhizal effects were most pronounced in the nitrate treatment. Ammonium enhancement of phosphorus uptake was demonstrated for both mycorrhizal and control seedlings. Rhizosphere pH was altered by nitrogen source and the presence of mycorrhizas. Ammonium fertilization decreased pH, while nitrate fertilization increased pH.

Comparative water relations of container-grown and bare-root ectomycorrhizal and nonmycorrhizal Quercus velutina seedlings

Abstract: A 2 × 2 factorial field experiment was conducted with black oak (Quercus velutina) to examine the effects of seedling production method (container-grown vs. bare-rooted) and inoculation with Pisolithus tinctorius on seedling water relations and soil–plant liquid flow resistance (Rs-P). Over the study period, bare-rooted and noninoculated seedlings exhibited midday values of leaf water potential (Ψ) which were lower than container-grown and Pisolithus-inoculated seedlings. During a mild drought in July similar trends were seen in predawn Ψ. Flow resistance between bulk soil and leaf was lower in container-grown and Pisolithus-inoculated plants than in bare-rooted and noninoculated plants; Rs–p was particularly high in bare-rooted plants which were not inoculated with Pisolithus. The exact mechanism(s) accounting for the differences in Rs–p of mycorrhizal vs. nonmycorrhizal plants could not be ascertained by the techniques employed. Low Rs–p in container-grown plants was associated with greater total root s...

The sorghum embryo in relation to the hydrolysis of the endosperm during germination and seedling growth

Abstract: Time-course changes in the structural and physiological properties of sorghum grain embryo have been investigated in relation to the hydrolysis of the endosperm during germination and seedling growth Histochemical analysis showed that the reserve food materials of the scutellum tissue were metabolised rapidly during germination and seedling growth Light microscope analysis of structural changes showed that scutellar epithelial cell elongation was associated with endosperm reserve mobilisation Electron microscope studies verified preliminary histochemical and light microscope findings and showed that extensive metabolism of subcellular storage materials occurred during early germination and seedling growth Physiological evidence indicated that both sorghum embryo and endosperm were insensitive to the gibberellic acid, GA3 Other hormones such as indole-3-acetic acid and kinetin also failed to induce α-amylase production This suggests that the hormonal response of the aleurone of sorghum is different from that of barley aleurone Dissection of sorghum showed that the whole body of the scutellum was capable of producing α-amylase

Prolific plant regeneration from protoplast-derived tissues of Lotus corniculatus L. (birdsfoot trefoil).

Abstract: Protoplasts isolated enzymatically from seedling roots, hypocotyls and cotyledons of Lotus corniculatus L. produced callus which underwent prolific shoot regeneration. The rapidity and ease of recovering plants from protoplast-derived tissues makes this forage legume an attractive experimental system for genetic manipulation.