Productivity of Peach Trees : Tree Growth and Water Stress in Relation to Fruit Growth and Assimilate Demand

The growth of the limbs of peach trees measured by dendrometerswas inhibited during periods when the rate of d. wt accumulationby the fruit was increasing. The diurnal shrinkage of theselimbs measured by the same dendrometers was greatest duringperiods when limb growth was inhibited. The increase in diurnalshrinkage of the limbs coinciding with inhibited limb growth,and increased assimilate demand, was greater than that causedby environmental factors at maximum soil water-potential andgreater than that caused by five days soil drying after irrigation.Leaf water potential and diurnal limb shrinkage were measuredcontinuously during two periods of maximum soil water-potentialand leaf area when the rate of d. wt increase of the fruit wasdecreasing (DW II) and then later when the rate of d. wt increaseof the fruit was increasing (DW III). The leaf water potentialwas lower and limb shrinkage greater during DW 111 than DW II.The hydraulic gradient also increased from 1 bar m^–1 inDW II to 2 bar m^–1 in DW III Environmental conditions during both periods were very similarand the data suggest total water use by the tree increased substantiallyduring periods of high assimilate demand by the fruit.     

Accrescimento del pericarpo,seme, endosperma ed embrione in prunus Amygdalus stokes

Abstract

GROWTH OF PERICARP, SEED, ENDOSPERM, AND EMBRYO IN PRUNUS AMYGDALUS STOKES. — The fruits of an almond-tree growing at Bari were collected weekly from February 22nd to July 11th and on August 16th 1960. The material was kept in fixative; the growth of the various organs was studied both from a morphological and a quantitative point of view. Special attention was given to growth of the endosperm, especially during the nuclear stage and at the beginning of cellularisation (Figg. 1-14), and to the developement of the embryo until it reaches the « heart-shaped » stage (Figg. 15–22). From a quantitative point of view, the volume and main diameters of pericarp and seed, and whenever possible endosperm and embryo, were measured for each fruit. Most of the data are given in Tables I to V and Figg. 23 and 24.

If reference is made to the 3 phases of fruit growth established for other species (notably peaches and cherries), the main conclusions are that:

1. phase I (growth of pericarp, testa and nucellus) is clearly recognisable; it ends after the micropylar portion of the endosperm has become cellular and the embryo heart shaped;

2. phase II is also present: during this phase most of the growth of endosperm and embryo takes place; while the seed has reached its definite size at the end of phase I, the pericarp undergoes a period of greatly reduced growth;

3. two weeks after the beginning of phase II the pericarp seems to resume growth just for a very short period, judging at least by the weekly values of the ratio pericarp volume to seed volume (see Fig. 23); this seems to indicate the existence of a new phase, that is phase III, which in fleshy fruits of the genus Prunus corresponds to a much longer and important process of pericarp growth than in the almond;

4. as in the peaches and cherries therefore a crisis in pericarp growth occurs during the period of maximum rate of growth of the cellular endosperm and embryo;

5. the sequence: cellularisation of the endosperm, growth of endosperm and embryo, ceasing of seed growth, and reduction in pericarp growth is very clear, particularly if we take into account growth in length rather than in volume; both morphological and quantitative data would indicate the importance of the endosperm not only for the beginning of embryo development, but also for the control of pericarp growth.

     

Growth and proteomic analysis of tomato fruit under partial root-zone drying

The effects of partial root-zone drying (PRD) on tomato fruit growth and proteome in the pericarp of cultivar Ailsa Craig were investigated. The PRD treatment was 70% of water applied to fully irrigated (FI) plants. PRD reduced the fruit number and slightly increased the fruit diameter, whereas the total fruit fresh weight (FW) and dry weight (DW) per plant did not change. Although the growth rate was higher in FI than in PRD fruits, the longer period of cell expansion resulted in bigger PRD fruits. Proteins were extracted from pericarp tissue at two fruit growth stages (15 and 30 days post-anthesis [dpa]), and submitted to proteomic analysis including two-dimensional gel electrophoresis and mass spectrometry for identification. Proteins related to carbon and amino acid metabolism indicated that slower metabolic flux in PRD fruits may be the cause of a slower growth rate compared to FI fruits. The increase in expression of the proteins related to cell wall, energy, and stress defense could allow PRD fruits to increase the duration of fruit growth compared to FI fruits. Upregulation of some of the antioxidative enzymes during the cell expansion phase of PRD fruits appears to be related to their role in protecting fruits against the mild stress induced by PRD.     

Indole-3-acetic acid content and glutamine synthetase activity in the pericarp,and peroxidase activity and isoenzymes in the meso- and exocarp of growing peach fruits

The indole-3-acetic acid (IAA) content in peach pericarp (Prunus persica L. Batsch cv. Merry) was highest at early stage I of development (～200 ng/g fresh wt), decreased to the lowest level during stage II, and rose again at stage III to 60–70 ng/g fresh wt. High activity of glutamine synthetase was found in the pericarp during stage I. The soluble peroxidase activity was highest in the meso- and exocarp at stage II, and isoenzymatic changes in this fraction corresponded to the transition from cationic isoenzymes, predominant at stage I, to anionic isoenzymes at stage III. The ionically bound peroxidase activity in these tissues was highest at stage I. The three developmental stages showed marked differences in auxin content and enzyme activities; for peroxidases these changes reflect a developmental expression pattern for the isoenzymes.     

Cytokinins in peach: Endogenous levels during early fruit development

Endogenous cytokinins have been studied in peach (Prunus persica [L.] Batsch). By means of coupled gas chromatography and mass spectrometry methods and using isotope-labelled standards, eleven cytokinin metabolites were quantified and endogenous levels followed during early fruit development. Analysis of cytokinins was performed on a separate basis for seed and pericarp, and correlated with growth and developmental events of fruit. Results show the prevalence of isopentenyladenine nucleotide, dihydrozeatin riboside and dihydrozeatin nucleotide, during the setting and exponential growth of fruit. Exceptionally high levels of zeatin riboside and dihydrozeatin nucleotide are also found in the seed, correlating with endosperm development and embryo growth during early fruit development. The putative role of these metabolites is discussed.     

Endogenous Gibberellin Profile During Christmas Rose (Helleborus niger L.) Flower and Fruit Development

Gibberellins (GAs) were identified and quantified during flower and fruit development in the Christmas rose (Helleborus niger L.), a native of southeastern Europe with a long international horticultural tradition. Physiologically, the plant differs from popular model species in two major respects: (1) following anthesis, the initially white or rose perianth (formed in this species by the sepals) turns green and persists until fruit ripening, and (2) the seed is shed with an immature embryo, a miniature endosperm, and a prominent perisperm as the main storage tissue. GA₁ and GA₄ were identified by full-scan mass spectra as the major bioactive GAs in sepals and fruit. LC-MS/MS system in accord with previously verified protocols also afforded analytical data on 12 precursors and metabolites of GAs. In the fruit, GA₄ peaked during rapid pericarp growth and embryo development and GA₁ peaked during the subsequent period of rapid nutrient accumulation in the seeds and continued pericarp enlargement. In the sepals, the flux through the GA biosynthetic pathway was highest prior to the light green stage when the photosynthetic system was induced. Unfertilized, depistillated, and deseeded flowers became less green than the seed-bearing controls; chlorophyll accumulation could be restored by applying GA₁, GA₄, and, less efficiently, GA₃ to the deseeded fruit. The sepals of unfertilized and depistillated flowers indeed contained very low levels of GA₄ and gradually decreasing levels of GA₁. However, the concentrations of their precursors and metabolites were less affected. These data suggest that a signal(s) from the fruit stimulates GA biosynthesis in the sepals resulting in greening. The fruit-derived GAs appear to be mainly involved in pericarp growth and seed development.     

Sequential Expression of Trypsin Inhibitors in Developing Fruit of Cowpea (Vigna unguiculata (L.) Walp)

Trypsin inhibitor (TI) activity was followed in the pod (pericarp),seed coat, cotyledon and embryo axis during fruit developmentof cowpea. On the basis of seed fresh weight, three phases couldbe distinguished from anthesis to fruit maturity. In the podTI activity increased from the beginning of Phase I to a maximumin the middle of the phase. From then on the activity declineduntil no activity could be detected before the end of phaseII. The cotyledons did not contain any TI in Phase I. TI activitywas first detected in the cotyledon in the beginning of PhaseII at the same time that globulin synthesis started. The TIactivity in the cotyledon increased to a maximum at the endof Phase II before decreasing in Phase III. In the embryo axisa similar pattern of TI activity to that of the cotyledon wasfound. No protein TI could be detected in the seed coat at anystage. In the pod there is a TI with a mol. wt of 12500 andpI of 4.4. Mature cotyledon and embryo axis have two TI withmol. wt 10800 and 24700 with pI 4.7 and 5.0 respectively. Duringdevelopment the smaller TI (mol. wt 10800) was synthesised beforethe larger TI (mol. wt 24700). There were large differencesbetween the maximum absolute amounts of TI present in the pericarp,cotyledon and embryo axis.     

Ethylene biosynthesis in tissues of young and mature avocado fruits

Sitrit, Y., Blumenfeld, A. and Riov, J. 1987. Ethylene biosynthesis in tissues of young and mature avocado fruits.
Avocado (Persea americana Mill.) fruit tissues differ greatly in their capability to pro duce wound ethylene. In fruitlets, the endosperm lacks the ability to produce ethylene because no 1-aminocyclopropane-1-carboxylic acid (ACC) is synthesized and no activity of the ethylene-forming enzyme (EFE) is present. The cotyledons (embryo) do not produce significant amounts of ethylene at any of the developmental stages of the fruits, although in both young and mature fruits they contain a relatively high level of ACC synthase (EC 4.4.1.-) activity. Because of the very low EFE activity present in the cotyledons, most of the ACC formed in this tissue is conjugated. Of the various fruitlet tissues, the seed coat has the highest potential to produce ethylene. This is due to a high ACC synthase activity and particularly a high EFE activity. Also, the seed coat is very sensitive to the autocatalytic effect of ethylene. Fruitletpericarp possesses a lower potential to produce ethylene than the seed coat. Towardruit maturiy, the endosperm disappears and the seed coat shrivels and dies so that the pericarp and the cotyledons remain as the only active tissues in the mature fruit. At this stage, the pericarp is the only tissue producing ethylene. Mature precli macteric pericarp has a lower potential to produce ethylene than fruitlet pericarpThe role of ethylene in regulating various physiological processes at different stages of fruit maturation is discussed.     

Indole-3-acetic acid content and glutamine synthetase activity in the pericarp, and peroxidase activity and isoenzymes in the meso- and exocarp of growing peach fruits

The indole-3-acetic acid (IAA) content in peach pericarp (Prunus persica L. Batsch cv. Merry) was highest at early stage I of development (200 ng/g fresh wt), decreased to the lowest level during stage II, and rose again at stage III to 60–70 ng/g fresh wt. High activity of glutamine synthetase was found in the pericarp during stage I. The soluble peroxidase activity was highest in the meso- and exocarp at stage II, and isoenzymatic changes in this fraction corresponded to the transition from cationic isoenzymes, predominant at stage I, to anionic isoenzymes at stage III. The ionically bound peroxidase activity in these tissues was highest at stage I. The three developmental stages showed marked differences in auxin content and enzyme activities; for peroxidases these changes reflect a developmental expression pattern for the isoenzymes.     

Kaffeinsynthese in Früchten und Gewebekulturen von Coffea arabica

Summary During fruit development the relative caffeine content of the pericarp falls from 1.68% to 0.24% on a dry weight basis, but remains more or less constant in the seed (about 1.25%). On an absolute basis, the pericarp has twice as much and the seed twenty times as much caffeine at maturity as at the beginning of fruit development. Tissue cultures of seed tissue (endosperm) produce caffeine and release it into the growth medium. Both pericarp and endosperm fed with NaH¹⁴CO₃ synthesize ring-labelled caffeine. Light strongly stimulates the methylation step of caffeine synthesis in the pericarp.

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Diese Arbeit wurde vom Schweizerischen Nationalfonds für wissenschaftliche Forschung unterstützt.     

Biochemical and genomic analysis of sucrose metabolism during coffee (Coffea arabica) fruit development

Sucrose metabolism and the role of sucrose synthase were investigated in the fruit tissues (pericarp, perisperm, and endosperm) of Coffea arabica during development. Acid invertase, sucrose phosphate synthase, and sucrose synthase activities were monitored and compared with the levels of sucrose and reducing sugars. Among these enzymes, sucrose synthase showed the highest activities during the last stage of endosperm and pericarp development and this activity paralleled closely the accumulation of sucrose in these tissues at this stage. Carbon partitioning in fruits was studied by pulse-chase experiments with (14)C-sugars and revealed high rates of sucrose turnover in perisperm and endosperm tissues. Additional feeding experiments with (14)CO(2) showed that leaf photosynthesis contributed more to seed development than the pericarp in terms of photosynthate supply to the endosperm. Sugar analysis, feeding experiments, and histological studies indicated that the perisperm plays an important role in this downloading process. It was observed that the perisperm presents a transient accumulation of starch which is degraded as the seed develops. Two full-length cDNAs (CaSUS1 and CaSUS2) and the complete gene sequence of the latter were also isolated. They encode sucrose synthase isoforms that are phylogenetically distinct, indicating their involvement in different physiological functions during cherry development. Contrasting expression patterns were observed for CaSUS1 and CaSUS2 in perisperm, endosperm, and pericarp tissues: CaSUS1 mRNAs accumulated mainly during the early development of perisperm and endosperm, as well as during pericarp growing phases, whereas those of CaSUS2 paralleled sucrose synthase activity in the last weeks of pericarp and endosperm development. Taken together, these results indicate that sucrose synthase plays an important role in sugar metabolism during sucrose accumulation in the coffee fruit.     

Allometry of within-fruit reproductive allocation in subtropical dicot woody species

Angiosperm fruits typically consist of pericarp and seed, which collectively function to maximize plant reproductive success. Within-fruit reproductive allocation has been scarcely examined across a wide range of fruit types and taxa although it is critical to the understanding of the evolution of fruit size and seed size. We investigated seed size, fruit size, seed number per fruit (SNF), and within-fruit biomass allocation between seed mass and pericarp mass for 62 dicot woody species (27 deciduous and 35 evergreen species) of a subtropical evergreen forest in southwest China. At the fruit level, total pericarp mass (TPM) isometrically scaled with increasing total seed mass (TSM) in the evergreen species and in the pooled data set, while TPM increased faster than TSM in the deciduous species. The slope difference is possibly due to the difference in the timing of fruit development between the two species groups. At the seed level, seed package (pericarp mass per seed) isometrically scaled with increasing seed size in the deciduous group, but less than isometrically in the evergreens and in the pooled data set. SNF was negatively correlated with seed size but positively correlated with the proportion of pericarp within fruits. In conclusion, within-fruit biomass allocation is significantly affected by seed size, fruit size, and SNF in both deciduous and evergreen species. The implications of the observed scaling relationships are discussed in relation to seed size evolution and global patterns of seed size variation.     

Independent Regulatory Aspects and Posttranslational Modifications of Two beta-Amylases of Rye : Use of a Mutant Inbred Line

We have examined the occurrence/disappearance, tissue location, and posttranslational modification of β-amylase proteins in rye (Secale cereale L.) kernels at three physiological stages (development, maturity, germination) with a normal inbred line and a mutant line exhibiting a high but incomplete β-amylase deficiency. This deficiency corresponds to a lack of accumulation of β-amylase activity in the endosperm and does not affect the level of activity in the outer pericarp and green tissues as compared to the normal line. Two antigenically related but distinct β-amylases (I and II) were detected in the normal line (II being the major constituent) and only one (I) in the mutant line. I and II display very similar electrophoretic polymorphism. In both lines, I appears to be ubiquitous, although it disappears from the outer pericarp during ripening. Antigen II was present only in the normal line and appears to be specific for the endosperm and perhaps for the maternal green tissues of the seed. Posttranslational modifications occurring during germination, which are mimicked by the action of papain, affect II but not I. The two groups of β-amylases are discussed in relation to recent reports indicating the presence of two types of β-amylase with different functions and gene loci in barley and wheat.     

宁夏枸杞果实与种子形态发育初探

研究了宁夏枸杞不同发育时期果实和种子形态的变化特征及种子内胚的变化.结果表明:宁夏枸杞果实的生长发育曲线为花后8d以前为其第一次快速生长期,花后8～24 d为缓慢生长期,花后24～34 d是第二次快速生长期,属于典型的双“S”型.宁夏枸杞种子的生长曲线既不属于单“S”型,也不属于双“S”型,表现为果实的第一次快速生长期同样也是种子的快速生长期,但种子完成的生长比例快于果实完成的生长比例,此期种子内的胚乳生长快;当果实进入缓慢生长期,种子也表现出缓慢生长的特性,且种子长度和宽度的增加速率均显著低于果实第一次快速生长期种子的生长速率,此期种子主要进行胚的分化;在果实的第二次快速生长期,果实体积和重量迅速增加,而种子的长度和宽度增加很少,此期种子内仅胚进一步增大,从而反映出宁夏枸杞果实的发育与种子发育有一定的相关性.     

Endogenous abscisic acid signaling towards storage reserve filling in developing seed tissues of castor bean (Ricinus communis L.)

Abscisic acid (ABA; free form) is a naturally occurring physiological growth hormone of higher plants. A detailed study involving the time course growth of developing seed tissues associated with endogenous levels of free ABA were investigated using a novel enzyme-linked immunosorbent assay. Seed filling in castor (Ricinuc communis L.) endosperm, embryo, and pod is marked with a rapid increase in fresh weight during the mid-developmental stages [21–42 days after pollination (DAP)], followed by a steady decline at the maturation stages (42–63 DAP) accompanied with a rapid lipid synthesis (in endosperm and embryo) during the same period, except for in pod. Endogenous ABA levels in endosperm (0.001–0.32 μg/g) and embryo (0.003–0.13 μg/g) followed a concurrent pattern with seed reserve filling, showing a rapid increase during the mid-developmental stages 21–42 DAP, whereas ABA levels in seed pod (0.2–22.9 μg/g) showed a different accumulation pattern with rapid increase and decline during the early-mid developmental stages, preceded by the maximal increase during the maturation stage (63 DAP). Together, our results provide evidence for the association of endogenous ABA in seed filling as well as in reserve deposition and provides clue for the effective usage of exogenous ABA concentrations in developing seeds with a focus, on improving seed reserve complex in castor.     

Phosphorylases I and II of Maize Endosperm

Two phosphorylases have been found in the endosperm of Zea mays. Phosphorylase I is found through all stages of endosperm development and seed germination investigated. The other enzyme, phosphorylase II appears only at the stage of rapid starch biosynthesis and is not found during germination. At 22 days after pollination, the activity of phosphorylase II is 10 times that of phosphorylase I. These 2 phosphorylases are separable by column chromatography and behave differently in several respects.     

The Morphology of Fruits and Starches in Bamboos,and Its Relation to Systematic Position

In this article, 30 speceis of bamboos, including 19 genera in 5 tribes, were collected and the morphology of fruits and starches of them was studied. The results are as follows. I. The morphology of fruits is important in studies of systematic position in bamboos. According to the systems of W. Munro and G. Bentham whether the pericarp is adhesive to or free from the seed coat may be taken as a basis of classification. It is also confirmed in this article. It is found in this work that all taxa with a binding pericarp and seed coat are of caryopsis that also has a ventral suture and hilum, while all others with a separated pericarp and seed coat are of bacca or nut, which has no ventral suture and hilum. The former has a hard and thin pericarp and rich endosperm, while the latter has a fleshy and thick pericarp and no endosperm. These characteristics form a basis of classification of major groups. II. In 1907, Brandis found that no any endosperm in matured fruit of Dinochloa, Melocalamus, Melocanna and Ochlandra. It has been proved by Stapf in at least one genus. We found that the baccae of Qiongzhuea, Melocanna, Ferrocalamus and Chimonobambusa Subg. Oerocalama were empty, with no endosperm. This may be a common character of the bacca. We believe, therefore, that the systematic position of Qiongzhuea, Ferrocalamus and Chimonobambusa Subg. Oreocalama is close to Melocanneae. III. Starch grains of bamboo fruits are complex in structure. They are round or ellipsoidal, consisting of 3-22 polyhedral or apple-like small grains. The morphology of starch grains is not so important as fruit in bamboo classification, but some characteristics are of a high value in the identification of genera and species, when they are combined with other features. In Cephalostachyum, the starch grain is very big, with 20-40 μm in diam, and the starch small grain is polyhedral or apple-like with 7.5-22.5 μm in diam, while in Dendrocalamus, the starch grain is small, with 10-28.9 μm in diam. and the starch small grain is only polyhedral, with 3-11.9 μm in diam. The morphology and size of the starch grain and starch small grain are also different in Melocanna and Chimonobambusa Subg. Oreocalama. IV. W. Munro’s system divided Bambuseae into three major groups according to the morphology of flower and fruit. Because the material was not sufficient at that time, the system wrongly put Cephalostachyum, Dendrocalamus into the group Bacciferea. Now it is found that both Cephalostachyum and Dendrocalamus have a nut. Later G. Bentham found this problem and divided the Bambuseae into four subtribes, treating Dendrocalamus as a separate subtribe, Dendrocalamae, and putting the bacca group into another subtribe, Melocannae. It is better, but it also has some shortcomings. Hackel, Gamble, E. G. Camus, A. Camus and Keng Pojie all accepted the view of Bentham, placing Dendrocalamus and Melocanna into different subtribes or tribes.