Showing papers on "Endosperm published in 1979"
TL;DR: The time sequence analysis of the starch digestion pattern of the thin sectioned germinating rice (Oryza sativa L.) seed specimens using the starch film method showed that at the initial stage amylase activity was almost exclusively localized in the epithelium septum between the scutellum and endosperm.
Abstract: The time sequence analysis of the starch digestion pattern of the thin sectioned germinating rice (Oryza sativa L) seed specimens using the starch film method showed that at the initial stage amylase activity was almost exclusively localized in the epithelium septum between the scutellum and endosperm Starch breakdown in the endosperm tissues began afterward; amylase activity in the aleurone layers was detectable only after 2 days Polyacrylamide gel electrofocusing (pH 4 to 6) revealed nearly the same zymogram patterns between endosperm and scutellum extracts, although additional amylase bands appeared in the endosperm extracts at later germination stages (4 to 6 days) These are presumably attributable to the newly synthesized enzyme molecules in the aleurone cells
171 citations
135 citations
TL;DR: The subcellular localization of the starch biosynthetic and degradative enzymes of spinach leaves was carried out by measuring the distribution of the enzymes in a crude chloroplast pellet and soluble protein fraction and by the separation on sucrose density gradients of intact organelles, chloroplasts, peroxisomes, and mitochondria of a protoplast lysate.
Abstract: The subcellular localization of the starch biosynthetic and degradative enzymes of spinach leaves was carried out by measuring the distribution of the enzymes in a crude chloroplast pellet and soluble protein fraction, and by the separation on sucrose density gradients of intact organelles, chloroplasts, peroxisomes, and mitochondria of a protoplast lysate. ADP-Glucose pyrophosphorylase, starch synthase, and starch-branching enzymes are quantitatively associated with the chloroplasts. The starch degradative enzymes amylase, R-enzyme (debranching activity), phosphorylase, and D-enzyme (transglycosylase) are observed both in the chloroplast and soluble protein fractions, the bulk of the degradative enzyme activities reside in the latter fraction. Chromatography of a chloroplast extract on diethylaminoethyl-cellulose resolves the R- and D-enzymes from amylase and phosphorylase activities although the two latter enzyme activities coeluted. The digestion pattern of amylase with amylopectin as a substrate indicates an endolytic activity but displays properties unlike the typical α-amylase as isolated from endosperm tissue.
129 citations
TL;DR: An enzyme which catalyzes the release of soluble β-glucan from insoluble barley endosperm cell walls is described in this article, which increases in activity throughout malting.
Abstract: An enzyme is described which catalyzes the release of soluble β-glucan from insoluble barley endosperm cell walls. This enzyme increases in activity throughout malting. It has been partially purified and found to behave in the same way as an acidic carboxypeptidase on isoelectric focusing and in its sensitivity to inhibitors and activators and to heating. The importance of the β-glucan solubilizing enzyme in malting and mashing is discussed.
An improved method for β-glucan determination is described.
92 citations
TL;DR: The galactomannan is clearly a dual-purpose polysaccharide, regulating water-balance during germination and serving as a substrate reserve for the developing seedling following germination.
Abstract: Some 30% of the reserve material in the fenugreek seed is galactomannan localised in the endosperm; the remainder is mainly protein and lipid in the cotyledons of the embryo. The importance of galactomannan to the germinative physiology of fenugreek has been investigated by comparing intact and endosperm-free seeds. From a purely nutritional point of view the galactomannan's role is not qualitatively different from that of the food reserves in the embryo. Nevertheless, due to its spatial location and its hydrophilic properties, the galactomannan is the molecular basis of a mechanism whereby the endosperm imbibes a large quantity of water during seed hydration and is able to “buffer” the germinating embryo against desiccation during subsequent periods of drought-stress. The galactomannan is clearly a dual-purpose polysaccharide, regulating water-balance during germination and serving as a substrate reserve for the developing seedling following germination. The relative importance of these two roles is discussed.
89 citations
TL;DR: The plastids contain some enzymes of the pentose phosphate pathway, pyruvate dehydrogenase and fatty acid synthetase in addition to the set of glycolytic enzymes, which suggests that the role of the plastid in the endosperm of germinating castor bean is the production of fatty acids from sugar phosphates, as it is known to be in theendosperm during seed development.
Abstract: The intracellular distribution of enzymes capable of catalyzing the reactions from oxaloacetate to sucrose in germinating castor bean endosperm has been studied by sucrose density gradient centrifugation. One set of glycolytic enzyme activities was detected in the plastids and another in the cytosol. The percentages of their activities in the plastids were less than 10% of total activities except for aldolase and fructose diphosphatase. The activities of several of the enzymes present in the plastids seem to be too low to account for the in vivo rate of gluconeogenesis whereas those in the cytosol are quite adequate. Furthermore, phosphoenolypyruvate carboxykinase, sucrose phosphate synthetase, and sucrose synthetase, which catalyze the first and final steps in the conversion of oxaloacetate to sucrose, were found only in the cytosol. It is deduced that in germinating castor bean endosperm the complete conversion of oxaloacetate to sucrose and CO2 occurs in the cytosol. The plastids contain some enzymes of the pentose phosphate pathway, pyruvate dehydrogenase and fatty acid synthetase in addition to the set of glycolytic enzymes. This suggests that the role of the plastid in the endosperm of germinating castor bean is the production of fatty acids from sugar phosphates, as it is known to be in the endosperm during seed development.
87 citations
TL;DR: An indication of the metabolic capacity of the plastids was determined by monitoring the ribulose-1,5-bisphosphate carboxylase activity in the endosperm.
Abstract: During castor oil seed development, changes occur in the activities of enzymes involved in fatty acid biosynthesis, glycolysis, and the pentose phosphate pathways. The activities of acetyl-CoA carboxylase, phosphofructokinase, pyruvate kinase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase per seed increase during the phase of rapid oil synthesis in the endosperm. As the seed matures and the rate of fatty acid synthesis decreases, there is a corresponding diminution in the activities of these enzymes. An indication of the metabolic capacity of the plastids was determined by monitoring the ribulose-1,5-bisphosphate carboxylase activity in the endosperm.
82 citations
TL;DR: It is concluded that the rain did not alter the structural nature of the acid-soluble β-glucan contents of barley flour and that the genotype having the lys-3a allele is characterized by such a low extract viscosity and β- glucan content that theRain had no effect on these parameters.
Abstract: The effect of rain on the viscosity of an acid flour extract and on the acid-soluble, acid-insoluble and total β-glucan contents of barley flour has been investigated. Four commercial varieties and two high lysine genotypes were studied. In the commercial varieties rain induces a decrease in the viscosity of the acid flour extract which is paralleled by decreases in soluble and total β-glucan contents. Furthermore, it is concluded that the rain did not alter the structural nature of the acid-soluble β-glucans. The genotype having the lys-3a allele is characterized by such a low extract viscosity and β-glucan content that the rain had no effect on these parameters. The rain had a very unexpected effect on the genotype having the lys allele, namely, a marked decrease in extract viscosity that was not accompanied by a decrease in β-glucan contents. Similar analyses on pure endosperm demonstrated that the rain effect is not a result of an altered 1000-grain weight. In addition, the extract viscosity and the soluble β-glucan content were found to decrease from yellow to full ripeness.
72 citations
TL;DR: The protein composition of the vacuoles are compared with that of the original protein bodies, and it is shown that hydrolysis of the endogenous protein continues in the isolated vacuole which are free from other cellular components.
Abstract: THE vacuoles of higher plant cells are known to be sites of deposition of salts and metabolites. A role as the lytic compartment has also been proposed1, and Matile has argued that the vacuole participates in the metabolism of higher plant cells in the same way that lysosomes do in other organisms. Recently, isolation methods have been developed which allow a direct analysis of vacuolar constituents and we have shown previously that the vacuoles isolated from the endosperm of young castor bean seedlings contain at least 25% of the cellular protein, 62% of the sucrose and various hydrolytic enzymes (acid protease, carboxypeptidase, phosphodiesterase, RNAase, phytase and β-glucosidase) in amounts indicating a primarily (possibly exclusive) vacuolar localisation2. In this tissue it is known that when the dry seed imbibes water the outer, water-soluble matrix of the protein bodies is dissolved and small vacuoles containing the protein crystalloid are formed. These coalesce early in germination to form the large central vacuole, and the remnants of the protein bodies disappear within a few days as growth proceeds3. We have examined vacuoles isolated from the endosperm of 4-d-old seedlings, when it is known that a net loss of protein is occurring. Here we compare the protein composition of the vacuoles with that of the original protein bodies, and show that hydrolysis of the endogenous protein continues in the isolated vacuoles which are free from other cellular components.
68 citations
TL;DR: Pericarp lipids and endosperm nonstarch lipids appeared to have suffered extensive degradation at some time during kernel development or after harvesting, while lipids in starch, germ and tip cap were evidently unaffected.
Abstract: The quantitative distribution of 23 acyl lipid classes and unsaponifiable matter in kernels of amylomaize, LG-11 hybrid maize and waxy maize is described. LG-11 and waxy maize were normal (oil content) varieties, containing 4.9% and 5.1% lipid, respectively, while amylomaize (9.3% lipid) was a high oil variety. The distribution of kernel lipids was 76–83% in germ, 1–2% in pericarp, 1% in tip cap, 1–11% in starch, and 13–15% in aleurone plus the nonstarch fraction of the starchy endosperm. Germ contained 39–47% lipid, which was nostly triglyceride (TG), with some steryl esters (SE) and diglycerides (DG), and small amounts of glycolipids (GL) and phospholipids (PL). Aleurone lipids appeared to be TG with some free fatty acids (FFA) and SE. The other nonstarch lipids in starchy endosperm were FFA with very small amounts of SE, DG, GL and PL. The starches had a little surface lipid (FFA) and true (internal) starch lipid (FFA, lyso-PL) in quantities roughly related to amylose content (amylomaize =ca. 73% amylose, 1.0% lipid; LG-11=23% amylose, 0.7% lipid; waxy maize =<5% amylose, 0.2% lipid). Pericarp lipids (0.8–2.5%) were mainly unsaponifiable matter, the acyl lipids being TG, SE, DG and FFA. Tip cap lipids (2.5–2.9%) had more TG, GL and PL than pericarp lipids, but were otherwise similar. Pericarp lipids and endosperm nonstarch lipids appeared to have suffered extensive degradation at some time during kernel development or after harvesting, while lipids in starch, germ and tip cap were evidently unaffected. FFA and lyso-PL are regarded as normal components of maize starch (rather than degradation products) and may occur as amylose inclusion complexes.
61 citations
TL;DR: The citrate-stimulated reaction could be explained by an increased affinity for this endogenous primer and is dependent upon several factors including endogenous primer concentration, citrate concentration as well as branching enzyme concentration.
Abstract: Chromatography of extracts of maize on diethylaminoethyl-cellulose resolves starch synthase activity into two fractions (Ozbun, Hawker, Preiss 1971 Plant Physiol 48: 785-769). Only starch synthase I is capable of synthesis in the absence of added primer and the presence of 0.5 molar citrate. This enzyme fraction has been purified about 1,000-fold from maize kernels homozygous for the endosperm mutant amylose-extender (ae). Because ae endosperm lacks the starch-branching enzyme which normally purifies with starch synthase I, the final enzyme fraction was free of detectable branching enzyme activity. This allowed a detailed characterization of the citrate-stimulated reaction. The citrate-stimulated reaction was dependent upon citrate concentrations of greater than 0.1 molar. However, the reaction is not specific for citrate and malate also stimulated the reaction. Branching enzyme increased the velocity of the reaction about 4-fold but did not replace the requirement for citrate. Citrate reduced the K(m) for the primers amylopectin and glycogen from 122 and 595 micrograms per milliliter, respectively, to 6 and 50 micrograms per milliliter, respectively. The enzyme was found to contain 1.7 milligrams of anhydroglucose units per enzyme unit. Thus reaction mixtures contained 1 to 5 micrograms (5 to 25 micrograms per milliliter) of endogenous primer. The citrate-stimulated reaction could be explained by an increased affinity for this endogenous primer. The starch synthase reaction in the absence of primer is dependent upon several factors including endogenous primer concentration, citrate concentration as well as branching enzyme concentration.
TL;DR: Flavonoid 3-O-glucosyltransferase, involved in anthocyanin biosynthesis, is controlled by at least four genes (Bz, C, R and Vp) in the maize endosperm and reaches its highest level at maturity.
Abstract: The enzyme UPD glucose: flavonoid 3-0-glucosyltransferase (UFGT), involved in anthocyanin biosynthesis, is controlled by at least four genes ( Bz, C, R and Vp ) in the maize endosperm. Bz is the structural gene for the enzyme. Early in endosperm development, the enzyme is present in an uninduced low level that is independent of C, R and Vp , and dependent solely on Bz . Beginning at about the fourth week of development, C, R and Vp interact with each other to induce high levels of UFGT. The enzyme accumulates thereafter in normal endosperms, reaching its highest level at maturity. The nature of the developmental signal (s) controlled by C, R and Vp is discussed.
TL;DR: The genetic control of major wheat endosperm proteins by homoeologous group 1 chromosomes has been studied by two-dimensional polyacrylamide gel electrophoresis and six protein subunits have been shown to be controlled by chromosome 1C(u) of the related species, Aegilops umbellulata.
Abstract: The genetic control of major wheat endosperm proteins by homoeologous group 1 chromosomes has been studied by two-dimensional polyacrylamide gel electrophoresis. The control of at least 15 distinct protein subunits or groups of protein subunits has been allocated to chromosomes 1A, 1B and 1D of Chinese Spring wheat from the analysis of grains of aneuploid genotypes. In addition, six protein subunits have been shown to be controlled by chromosome 1Cu of the related species, Aegilops umbellulata, from studies of wheat lines carrying disomic substitutions of 1Cu chromosomes. On the basis of protein subunit patterns, chromosome 1Cu is more closely related to chromosome 1D of wheat than to chromosomes 1A or 1B.
TL;DR: Endo-β-mannanase (EC 3.2.1.78) is produced and secreted by the cells of the endosperm of lettuce “seeds” (achenes) and may be involved in the control by the axis of the rest of the seed.
Abstract: Endo-β-mannanase (EC 3.2.1.78) is produced and secreted by the cells of the endosperm of lettuce (lactuca sativa L.) “seeds” (achenes). In imbibed intact seeds, production is prevented by inhibitors. If the endosperm is incubated alone, these inhibitors can be removed by leaching, allowing mannanase production. Abscisic acid, a component of lettuce seeds, inhibits the production of mannanase in the isolated endosperm, and may be involved in regulation of mannanase production in intact seeds. During germination the inhibition is removed, beginning 4–8 h after red-light irradiation, which was given 4 h from sowing. The cotyledons participate in this process, and are controlled by events occuring in the axis within 4 h from red-light irradiation. This control by the axis apparently depends on the exchange of diffusible substances. Both benzyladenine and gibberellic acid can replace the influence of the axis if the latter is removed, and may therefore be involved in the control by the axis of the rest of the seed.
TL;DR: The results indicate that the stimulus for breakdown of celery endosperm emanates from the embryo in response to light and the stimulus may be a gibberellin.
Abstract: Germination of celery seed occurred after 6 d of imbibition in light. During this time the embryo enlarged at the expense of the adjacent endosperm cells and at the time of germination was 2–3 times as long as in the dry seed. Breakdown of the endosperm cells near the root cap preceeded radicle emergence. None of these changes occurred in darkness. Endosperm digestion began adjacent to the embryo and spread radially. In degrading cells, the aleurone grains often became larger and fewer in number. The cell walls were modified and appeared to undergo partial degradation. Ultimately the cells seemed to lose their contents. In cells adjacent to the root cap, similar changes occurred except there was a transient appearance of starch grains. Radial progression of endosperm breakdown also occurred in isolated endosperm treated with gibberellin A4+7. The results indicate that (1) the stimulus for breakdown of celery endosperm emanates from the embryo in response to light; (2) the stimulus may be a gibberellin because changes in endosperm cells and the sequence of endosperm digestion during germination resemble the responses of isolated endosperm to gibberellin; and (3) the radial progression of endosperm breakdown during germination may be the result of a sequential response of cells to a uniformly applied stimulus rather than the result of gradual embryo expansion.
TL;DR: The slow drying characteristic and the reduced starch content previously reported for maturing seeds of IL677a may be related to the maltose accumulation reported here.
Abstract: The endosperm sugars of a new corn ( Zea mays L.) mutant, sugary enhancer ( se ), were analyzed by gas-liquid chromatography and were compared with sugars of other genotypes. Illinois 677a, a sugary ( su ) inbred containing the se gene, was high in sucrose and was distinguished from all of the other genotypes by its high maltose content. During kernel development, the maltose content of IL677a increased to 3.28% dry weight at 40 days postpollination and remained high at the dry mature stage, whereas `Silver Queen,9 a high quality sugary ( su ) hybrid not possessing the se gene, showed no such trend in maltose accumulation. Sucrose, fructose, and glucose decreased during kernel development in `Silver Queen9 and IL677a from 19 days postpollination until the dry mature stage. The slow drying characteristic and the reduced starch content previously reported for maturing seeds of IL677a may be related to the maltose accumulation reported here.
TL;DR: Responses to shading are taken as evidence for the existence of a mechanism operating during the early stages of grain development, before grain-filling begins, which can influence the capacity of the endosperm to accumulate starch.
Abstract: Plants of wheat (grown in a controlled environment) were subjected to brief (5-10 days) periods of shading just after the ears showed the first signs of anthesis, and afterwards were grown to maturity in full illumination. Shading resulted in smaller grains, slower rates of accumulation of dry matter in the grains, and lower final grain weights. Shading cut down contemporaneously the provision of sucrose to the developing grain but, soon after return to full illumination, the supply of sucrose was restored to levels observed in ears that had not been shaded. Moreover, the estimated concentrations of sucrose in the endosperm of grains that accumulated less dry matter as a result of shading were higher than in endosperm filling on the unshaded plants. Although shading resulted in lighter grains, the grains contained just as much protein as the unshaded ones. Trimming the ears (by removing some spikelets) of shaded plants did not influence grain weight. These responses to shading are taken as evidence for the existence of a mechanism operating during the early stages of grain development, before grain-filling begins, which can influence the capacity of the endosperm to accumulate starch. Capacity to accumulate protein is evidently not subject to the same kind of control.
TL;DR: In this paper, the authors compared several electrophorectic methods in terms of their reliability, convenience and ability to distinguish between varieties of wheat, barley, rye and triticale using proteins extracted from the endosperm with 1M urea.
Abstract: Several electrophorectic methods are compared in terms of their reliability, convenience and ability to distinguish between varieties of wheat, barley, rye and triticale using proteins extracted from the endosperm with 1M urea. Gradient gel electrophoresis offers an improvement, particularly in convenience, over the use of starch gels and uniform-pore polyacrylamide. Varietal identification is described using gels having gradients in polyacrylamide concentration of 3-27% or 2-16%, both being available commercially ready for use. Electrophoresis in the latter gels at 400 V takes only half an hour for barley and an hour for wheat. In addition, a simple procedure is described for gel isoelectric focusing which, used alone or in combination with gel electrophoresis, provides high resolution of endosperm proteins for distinguishing between closely related varieties.
TL;DR: The electrophoretic elution method described here allows, without additional equipment, simultaneous elution of up to 20 samples/elution gel and has shown to yield, directly and with good recovery, biologically active mRNA, plasmid DNA and double-stranded DNA fragments.
TL;DR: ATP citrate lyase (EC 4.3.1.8) has been found in crude extracts from endosperm tissue of germinating castor bean and shows its maximum activity in 4- to 5-day-old seedlings and a strict requirement for coenzyme A and adenosine 5'-triphosphate was demonstrated.
Abstract: ATP citrate lyase (EC 4.1.3.8) has been found in crude extracts from endosperm tissue of germinating castor bean and shows its maximum activity in 4- to 5-day-old seedlings. A strict requirement for coenzyme A and adenosine 5′-triphosphate was demonstrated. The pH optimum for the reaction is around 7.5. The unstable enzyme can be stabilized by freezing and addition of citrate and glycerol. (−)-Hydroxycitrate is a potent inhibitor. The molecular weight is about 400,000. The adenosine 5′-triphosphate citrate lyase is localized in the plastids, where it possibly plays a role in providing acetyl coenzyme A for lipid biosynthesis.
TL;DR: Th Thin layer chromatography of ethanolic or methanolic extracts of the cytosol, which contained greater than 95% of the radioactivity taken up by layers, revealed that labeled ABA was metabolized to phaseic acid (PA) and 4'-dihydrophaseic acid [DPA] and three polar metabolites Mx(1), Mx-2, and Mx (3).
Abstract: Aleurone layers of Hordeum vulgare, cv. ;Himalaya' took up [(14)C]-abscisic acid (ABA) when incubated for various times. Radioactivity accumulated with time in a low speed, DNA-containing pellet accounting for 1.6 to 2.3% of the radioactivity recovered in subcellular fractions at 18 hours. Thin layer chromatography of ethanolic or methanolic extracts of the cytosol, which contained greater than 95% of the radioactivity taken up by layers, revealed that labeled ABA was metabolized to phaseic acid (PA) and 4'-dihydrophaseic acid (DPA) and three polar metabolites Mx(1), Mx(2), and Mx(3). ABA was not metabolized by endosperm, incubated under conditions used for layers, indicating that metabolism was tissue-specific. Layers metabolized [(3)H]DPA to Mx(1) and Mx(2). ABA, PA, and DPA-methyl ester and epi-DPA-methyl ester inhibited synthesis of alpha-amylase by layers incubated for either 37 or 48 hours. These layers converted the methyl DPA and epi-methyl-DPA esters to their respective acids. DPA did not inhibit Lactuca sativa germination or root and coleoptile elongation of germinating Hordeum vulgare seeds, or coleoptile elongation of germinating Zea mays seeds.
TL;DR: In an attempt to understand the nonconcordance between the endosperm and pollen, extracts of mature pollen grains were assayed for a number of the enzymes possibly implicated in starch synthesis in theendosperm.
Abstract: Two mutations, amylose-extender and waxy, which affect the proportion of amylose and amylopectin of starch synthesized in the endosperm of maize (Zea mays L.) seeds, are also expressed in the pollen. However, most mutations that affect starch synthesis in the maize endosperm are not expressed in the pollen. In an attempt to understand the nonconcordance between the endosperm and pollen, extracts of mature pollen grains were assayed for a number of the enzymes possibly implicated in starch synthesis in the endosperm. Sucrose synthetase (sucrose-UDP glucosyl transferase, EC 2.4.1.13) activity was not detectable in either mature or immature pollen grains of nonmutant maize, but both bound and soluble invertase (EC 3.2.1.26) exhibited much greater specific activity (per milligram protein) in pollen extracts than in 22-day-old endosperm extracts. Phosphorylase (EC 2.4.1.1) activity was also higher in pollen than in endosperm extracts. ADP-Glucose pyrophosphorylase (EC 2.7.7.27) activity was much lower in pollen than endosperm extracts, but mutations that drastically reduced ADP-glucose pyrophosphorylase activity in the endosperm (brittle-2 and shrunken-2) did not markedly affect enzymic activity in the pollen. Specific activities of other enzymes implicated in starch synthesis were similar in endosperm and pollen extracts.
TL;DR: Immunohistochemical determination of the pattern of enzyme movement during germination and early seedling growth revealed that at the commencement of germination the α-amylase protein moiety moves away from the entire face of the scutellum and intermediate crushed cell layer.
Abstract: A procedure for the isolation of a germination-specific α-amylase isoenzyme from Hordeum vulgare (cv. Nordal) is described. The pure α-amylase isoenzyme was used to obtain a monospecific anti-α-amylase antibody. The antibody was subsequently used to localise α-amylase in sections of germinating barley seeds (cv. Nordal). Immunohistochemical determination of the pattern of enzyme movement during germination and early seedling growth revealed that at the commencement of germination the α-amylase protein moiety moves away from the entire face of the scutellum and intermediate crushed cell layer. As early seedling growth continues, the protein begins to be synthesised in the aleurone layer and transported away from this layer into the endosperm.
TL;DR: The high content of non protein nitrogen in the endosperm suggests the existence, in o7, of an early block in the synthetic route leading to proteins; this is particularly evident for zeins, the maize alcohol soluble storage proteins.
TL;DR: A new group of hydrophobic endosperm proteins from Triticum aestivum has been characterized, which have a higher proportion of sulphur amino acids and lower levels of glutamine and proline than the classical gliadins.
TL;DR: The severe delay in embryo and endosperm divisions may be the major cause of early pod abscission in P. vulgaris crosses.
Abstract: Fertilization and early embryo and endosperm development were examined in Phaseolus vulgaris x P. acutifolius, P. vulgaris x P. lunatus crosses and their reciprocals. The number and length of pollen tubes were not different between selfings and interspecific crosses. Fertilization was completed in all matings and the time of fertilization was maternally dependent which may reflect the degree of maturation of embryo sacs at pollination. A large difference between reciprocal crosses was found in the time of endosperm and embryo division in relation to the time of fertilization. When P. vulgaris was the female parent and P. acutifolius the male parent, endosperm division occurred at the same time as in P. vulgaris upon selfing, while in P. vulgaris x P. lunatus crosses the time of endosperm division was intermediate as compared with the two parents. The time lapse between fertilization and endosperm and embryo division in P. acutifolius x P. vulgaris crosses was longer than in either parent upon selfing. In P. lunatus x P. vulgaris crosses, endosperm division occurred in only 7–12% of the ovules at 72 hours after pollination. Embryo development in these ovules was limited to the four cell stage although the endosperm was at the free nuclei stage. The severe delay in embryo and endosperm divisions may be the major cause of early pod abscission in P. lunatus x P. vulgaris crosses.
TL;DR: The amino acid composition of the vascular sap of a high lysine maize mutant was determined during kernel development, and glutamine and arginine content decreased with maturity, while valine, methionine, isoleucine, leucines, tyrosine and phenylalanine increased with kernel development.
TL;DR: The developmental and histochemical aspects of the ovules of Nicotiana rustica L. were investigated, from the time of anthesis to the maturity of seeds, and starch was not observed in the embryo or endosperm at any stage of development.
Abstract: The developmental and histochemical aspects of the ovules of Nicotiana rustica L. were investigated, from the time of anthesis to the maturity of seeds. Pollination takes place on the day of anthesis and fertilization 1 day later. The endosperm development is ab initio cellular, and embryogeny conforms to the Solanad type. The seeds are albuminous, and a major portion of the seed is occupied by an embryo surrounded by a few layers of endosperm and the seed coat. Histochemical studies show that, before pollination, the integument contains numerous protein bodies, but at maturity the seed coat is devoid of proteins, and the embryo and endosperm are replete with proteins. Starch is absent in the integumentary cells of ovules from unpollinated ovaries and is present in small quantities in the central cell of the embryo sac. Immediately after pollination and fertilization the situation is reversed; integument cells now contain numerous starch grains. Starch was not observed in the embryo or endosperm at any st...