Aril Tissue Research Articles

Disrupted sugar transport and continued sugar consumption lead to sugar decline in ripe ‘Shixia’ longan fruit

Longan fruit pulp sugar content and sweetness decline after ripening, which affects fruit quality and postharvest storage. Fruit sugar decline research has focused mainly on fruit physiology and biochemistry. To explore the molecular mechanism underlying sugar decline, we conducted transcriptome and metabolome analyses of ‘Shixia’ longan fruit aril (pulp) tissues at different stages of development. In total, 873 metabolites and 26584 annotated unigenes were identified. Sugar content changes in aril tissues were closely related to gene expression patterns related to starch and sucrose metabolism, such as sucrose phosphate synthase (SPS), invertase (INV), sucrose synthase (SUS), and glucose-6-phosphate isomerase (GPI). Notably, glycolytic pathway gene expression and cellulose and lignin contents increased during the sugar decline stage compared to the sugar accumulation stage. Conversely, sucrose transporter genes, such as DlSWEET2b, DlSWEET10, and DlSWEET12, showed the opposite expression pattern, pointing to reduced sucrose transport during sugar decline. These results indicate that longan fruit sugar decline is likely related to an interruption of sugar input (cessation of sucrose transport to the aril) and continued glycolysis and cellulose/lignin biosynthesis. This provides a new way to delay longan fruit sugar decline, by regulating sugar transport instead of inhibiting respiration.

Effect of controlled atmosphere storage on pomegranate quality investigated by two dimensional NMR correlation spectroscopy

Pomegranate fruit was studied by two dimensional NMR correlation spectroscopy during 25 weeks of controlled atmosphere (CA) storage. The proton T1–T2 correlation spectrum provided rich information on the characteristics of the environment of water in subcellular compartments. Three relaxation components were identified in the pomegranate arils, which could be assigned to the vacuole, cytoplasm, and cell wall. The results showed that water transferred out of the vacuole to other compartments during storage. Shrinkage of the vacuole was expected as a result of the significant loss of water. The soluble solids content and titratable acidity of the pomegranate decreased during the controlled atmosphere storage, but they were not the major contributor to the change in the relaxation rate of water in the subcellular compartments of the aril tissue. The change in the aril was gradual and not uniform across the tissue in response to CA storage. The variation in the response of the arils to CA diminished at longer storage time.

Two GH3 genes from longan are differentially regulated during fruit growth and development

In the present work, two full length cDNAs of GH3 genes, named DlGH3.1 and DlGH3.2 were cloned from pericarp and aril tissues of the longan fruit, respectively. Three conserved motifs, SSGTSAGERK, YASSE and YRVGD, as a characteristic of the acyladenylate/thioester forming enzyme superfamily were observed in DlGH3.1 and DlGH3.2 proteins. DlGH3.1 mainly expressed in pericarp tissues while DlGH3.2 accumulated in both the pericarp and aril tissues during fruit growth and development. In addition, NAA treatment induced the expression of DlGH3.1 and DlGH3.2 in the pericarp tissues at 21 and 77 days after anthesis (DAA), while only DlGH3.2 in the aril tissues could be induced by NAA at 77 DAA. More importantly, ABA and ethrel treatments suppressed the accumulations of DlGH3.1 and DlGH3.2 in the pericarp tissues of longan fruit at 21 DAA (a rapid growth stage of pericarp), but enhanced DlGH3.2 expression in the aril tissues at 77 DAA (a fruit ripening stage). Furthermore, the expression patterns of DlGH3.1 and DlGH3.2 showed different tissue specificity. Thus, our results suggest that DlGH3.1 gene expression might be associated with pericarp growth, while DlGH3.2 accumulation is likely to be related to both pericarp growth and fruit ripening, and the responses of DlGH3s to plant growth hormones are different and dependent on fruit development stage and fruit tissue.

FRUIT SOFTENING DURING RIPENING - CAUSES AND REGULATION

Fleshy fruits have evolved repeatedly in several plant clades, including five times in Rosaceae. Different tissues have become the fleshy edible portion including the mesocarp, accessory tissues, aril, and flower tissue. Hence, ripening physiology may differ significantly between different species. Temporal and spatial differences exist between species in ethylene production and respiration rates and softening related changes. Papaya ripening illustrates some of the differences that can occur between species. Papaya has unique ripening variants in which skin and flesh color development is separated from respiratory rise and ethylene production, and softening. One variant softens to the edible stage in six days versus 11 days for the commercial varieties and another that does not begin to soften until 14 days from mature green stage and reaches the edible soft stage at 21 days. These papaya variants contrast sharply with the profound disruption shown by the tomato single gene ripening mutants. We have also purified a fruit ripening associated endoxylanase that is 32.5 kDa and coded for as a 64.96-kDa protein. The protein contains a secretory sequence, carbohydrate binding domain and the endoxylanase catalytic domain. Endoxylanase expression data from the ripening variants supports the possibility that it has a role in papaya mesocarp softening during ripening. The results suggest that different fruit may use different combinations of cell wall hydrolases to cause ripening related fruit softening. Tomato can be a model in that it can provide research direction. In a different fruit the results from tomato need to be confirmed at the gene expression, physiology and functional level.

Altered Physiology and Biochemistry of Imported Litchi Fruit Held under Different Vapor Pressure Deficits

The effects of vapor pressure deficit (VPD) on litchi fruit quality have not yet been fully defined. The aim of this study was to detail the changes in physiology, sugars, organic acids, and individual anthocyanin concentrations in imported litchi fruit held at various controlled relative humidity (RH) and VPD levels. SO(2)-fumigated (but not acid-treated) litchi imported from Thailand (cv. Kom) and from Israel (cv. Mauritius) were air freighted to the United Kingdom and then stored for 9 days at either 5 or 13 degrees C to simulate shelf-life conditions. Fruits were stored under a series of controlled RH conditions for the duration of the trial using different concentrations of glycerol in deonized water. Respiration rates and weight losses of both fruit lots were greater in litchi stored at 13 degrees C and a VPD of 0.274 kPa. At 5 degrees C and a VPD of 0 or 0.042 kPa, sugars and organic acids in aril and pericarp tissue and individual anthocyanins in pericarp were better maintained. This is the first piece of work that has systematically evaluated the effect of a series of VPDs on litchi fruit biochemistry such that implications for designing systems to better maintain the physiological quality of imported litchi fruit are discussed.

A distinct DGAT with sn -3 acetyltransferase activity that synthesizes unusual, reduced-viscosity oils in Euonymus and transgenic seeds

Endosperm and embryo tissues from the seeds of Euonymus alatus (Burning Bush) accumulate high levels of 3-acetyl-1,2-diacyl-sn-glycerols (acTAGs) as their major storage lipids. In contrast, the aril tissue surrounding the seed produces long-chain triacylglycerols (lcTAGs) typical of most other organisms. The presence of the sn-3 acetyl group imparts acTAGs with different physical and chemical properties, such as a 30% reduction in viscosity, compared to lcTAGs. Comparative transcriptome analysis of developing endosperm and aril tissues using pyrosequencing technology was performed to isolate the enzyme necessary for the synthesis of acTAGs. An uncharacterized membrane-bound O-acyltransferase (MBOAT) family member was the most abundant acyltransferase in the endosperm but was absent from the aril. Expression of this MBOAT in yeast resulted in the accumulation of acTAGs but not lcTAG; hence, the enzyme was named EaDAcT (Euonymus alatus diacylglycerol acetyltransferase). Yeast microsomes expressing EaDAcT possessed acetyl-CoA diacylglycerol acetyltransferase activity but lacked long-chain acyl-CoA diacylglycerol acyltransferase activity. Expression of EaDAcT under the control of a strong, seed-specific promoter in Arabidopsis resulted in the accumulation of acTAGs, up to 40 mol % of total TAG in the seed oil. These results demonstrate the utility of deep transcriptional profiling with multiple tissues as a gene discovery strategy for low-abundance proteins. They also show that EaDAcT is the acetyltransferase necessary and sufficient for the production of acTAGs in Euonymus seeds, and that this activity can be introduced into the seeds of other plants, allowing the evaluation of these unusual TAGs for biofuel and other applications.

DETERIORATION OF ANTHOCYANINS IN LITCHI 'KOM' FRUIT STORED UNDER DIFFERENT RELATIVE HUMIDITY LEVELS

The effects of relative humidity (RH) on litchi fruit quality have not yet been fully defined. The aim of this study was to detail the changes in physiology, non-structural carbohydrates (NSCs), and individual anthocyanin concentrations in imported litchi fruit held at various RH levels. Litchi 'Kom' fruit, imported from Thailand, was stored at 80, 85, 90, 95 or 100% RH using different concentrations of glycerol in deionised water, at 13°C for 9 days. Fruits (n=90) were individually measured for weight loss (%), hue (h°) and lightness (L*) values. Freeze-dried aril and pericarp tissue were individually extracted and analysed for NSCs and anthocyanins, respectively. Disease, mainly caused by Penicillium spp., was observed after 6 days storage which increased disease severity. Weight loss of fruit stored at 80% RH was significantly higher than at other RH levels, whilst 90% RH-stored fruit had a significantly higher h° over 9 days. The main NSCs in aril tissue were fructose (345.73 mg g -1 dry weight (DW)), glucose (329.08 mg g -1 DW) and sucrose (31.17 mg g -1 DW). There were no significant differences in NSCs concentration according to RH treatment. Generally, fructose and glucose concentrations increased during 9 days storage, whereas sucrose levels declined. The principal anthocyanins in pericarp tissue were cyanidin 3 rutinoside (1635.52 μg g -1 DW), cyanidin 3 glucoside (19.91 μg g -1 DW) and malvidin 3 glucoside (15.03 μg g -1 DW). All anthocyanins concentrations decreased after 9 days storage except fruit stored at 100% RH when anthocyanins increased. Anthocyanin levels from 80% RH-treated fruit were significantly lower than litchi held under higher RH conditions.

Control of Rotting and Browning of Longan Fruit cv. Biew Kiew after Harvested by Sulphur Dioxide Treatment under Various Storage Temperatures

The experiment of Longan fruit cv. Biew Kiew, untreated (control) and treated with SO2 treatment were stored under 2 +/- 2 and 7 +/- 2 degrees C for 0, 2, 4, 6 and 8 weeks were studied. The treatment of fresh longan fruit with SO2 fumigation combined with the suitable storage condition improved the overall longan fruit quality, especially on inner and outer peel tissue and aril color than no SO2 treatment. Treatment stabilizes peel color with no subsequent loss of color during storage (fruit color were bright-yellowish color). When the fruit showed during SO2 treatment, increasing of storage duration and temperatures, the dark color of inner and outer peel of longan fruit was appeared, this was correlated with the increasing of PPO activity. The activity of PPO enzyme in control fruit (no SO2 treatment) gradually lower than SO2 treatments. Fruit exposed to cool storage temperature (2 degrees C) exhibited a lower PPO enzymatic activity compared to those kept in high storage temperature (7 degrees C). Moreover, PPO enzymatic activity significantly increased over the storage durations The additional SO2 treatment no subsequent loss of weight of longan fruit during storage. However, the sulphite residues could detect immediately after SO2 treatment in all part of longan fruit, especially on aril tissue. The SEM evaluation found that the surface cracking was also impair the physiological function of the cuticle and increasing water permeability, which may cause water soaking at the inner side of the peel. The injured cell would accelerate the oxidation of phenolic substances and the oxidative products resulted in dark color of inner and outer peel.

Characterization and regulation of multiple forms of endo-1,4-β-glucanase genes during longan fruit growth and development

Endo-1,4-β-glucanase (EGase, EC 3.2.1.4) is proposed to be involved in the control of cell wall modification. However, the relationship between EGase and longan fruit growth remains obscure. In the present work, the expression profiles of three Dl-EGase genes in pericarp and aril tissues of longan fruit during growth and development were characterized; moreover, the effects of plant growth substances, naphthalene acetic acid (NAA) and thidiazuron (TDZ) on their expressions of fruits at two different developmental stages were also investigated. The results showed that high levels of EGase activities in aril were in accordance with rapid aril growth, and three Dl-EGase genes exhibited different expression patterns in pericarp and aril during fruit growth and development. Dl-EGase1 and Dl-EGase3 seemed to be associated with the growth of both pericarp and aril, while Dl-EGase2 was closely related to pericarp growth. In addition, treatment of NAA and TDZ at the stage of pericarp growth increased the EGase activities and induced the expressions of all the three Dl-EGases. However, when NAA or TDZ was applied at the rapid aril growth stage, the accumulations of Dl-EGase1 and Dl-EGase2 in the pericarp, and the accumulations of Dl-EGase1 and Dl-EGase3 in the aril were induced. Furthermore, the expression patterns of the three Dl-EGases showed different tissue specificity. It is thus speculated that Dl-EGase genes played a different role in longan fruit growth and were developmentally regulated, and more importantly, the responses of Dl-EGases to plant growth substances were different and dependent on fruit development stage and fruit tissue.

Expression analysis of endo‐1,4‐β‐glucanase genes during aril breakdown of harvested longan fruit

AbstractBACKGROUND: The aim of the present study was to investigate the expression profiles of three endo‐1,4‐β‐glucanase (EGase, EC 3.2.1.4) genes during aril breakdown of longan fruit stored at room temperature (25 °C), low temperature (10 °C) or on transferring fruit stored at 10 °C for 20 days to 25 °C.RESULTS: Three longan full‐length cDNAs, designated Dl‐EGase1, Dl‐EGase2 and Dl‐EGase3, were isolated and characterized. EGase activity in aril tissues of longan fruit increased with the appearance of aril breakdown symptoms, while RNA gel blot analysis revealed that the accumulations of three Dl‐EGase genes exhibited differential characteristics with the occurrence of aril breakdown. Dl‐EGase2 may be involved in the aril breakdown in longan fruit at the later stage of storage at room temperature. Conversely, expression of Dl‐EGase3 could be mainly involved in aril breakdown of fruit stored at 10 °C. In addition, Dl‐EGase3 and Dl‐Egase2 were related to the aril breakdown of fruit transferred from low temperature to room temperature.CONCLUSION: The results obtained in this study indicate that Dl‐EGase genes are involved in the aril breakdown of longan fruit and that considerable variation exists between expression patterns of individual members of the EGase gene family. Copyright © 2009 Society of Chemical Industry

Differential expression and regulation of longan XET genes in relation to fruit growth

Xyloglucan endotransglycosylase (XET) catalyses the transglycosylation of xyloglucan, the major hemicellulose polymer, which has been thought to mediate the cross-linking of cellulose microfibrils in cellular walls and proposed to be involved in the control of cell wall relaxation. To understand the relationship between longan fruit growth and XET gene expression patterns, three XET genes from fruit were identified and then their expression profiles in pericarp and aril tissues of fruit at different development stages were investigated. Three full-length cDNAs of 1077, 1093 and 1181 bp encoding XETs, named DlXET1, DlXET2 and DlXET3, respectively, were isolated from expanding fruit using RT-PCR and RACE-PCR (rapid amplification of cDNA ends) methods. Northern blotting analysis showed that three DlXET mRNAs exhibited different patterns during fruit growth and development. Accumulation of DlXET1 kept changeable during the fruit growth and development, Dl-XET2 mRNA accumulations in the pericarp and in the aril increased gradually following fruit growth during the whole fruit developmental stage. In addition, DlXET3 did not accumulate in the pericarp during the whole fruit development stage, but it could be detected in the aril of fruit during the rapid aril growth stage (63–74 DAA). These results indicated that DlXET2 was associated with growth of pericarp and aril in longan fruit, while DlXET1 was related to pericarp growth and DlXET3 was primarily responsible for aril growth. To further characterize the expressions of three XETs regulated by plant growth substances, α-naphthalene acetic acid (NAA) and thidiazuron (TDZ) were used to treat longan fruit at 21 DAA and 56 DAA when pericarp and aril grew rapidly respectively, it was found that treatment at 21 DAA, only TDZ increased the accumulation of DlXET2 mRNA at 12 h after treatment. However, both NAA and TDZ increased the accumulation of DlXET3 after 36 h treatment, although DlXET3 did not accumulate in the whole fruit. While, treatment at 56 DAA, both NAA and TDZ increased the accumulations of DlXETs in aril except DlXET3 in aril by NAA treatment. In addition, the expression patterns of the three XETs showed different tissue specificity. These results suggested that XET genes played a different role in longan fruit growth and showed different response to plant growth substances which existed difference at different growth stage.

Differential expression of litchi XET genes in relation to fruit growth

Xyloglucan endotransglycosylase (XET) catalyses the transglycosylation of xyloglucan, the major hemicellulose polymer, which has been thought to mediate the cross-linking of cellulose microfibrils in cellular walls and proposed to be involved in the control of cell wall relaxation. To understand the relationship between litchi fruit cracking and gene expression patterns, three XET genes from litchi fruit were identified and then examined for their expression profiles in pericarp and aril tissues at different development stages, using a cracking-resistant cultivar, ‘Huaizhi’, and a cracking-susceptible cultivar, ‘Nuomici’. Three full-length cDNAs of 1267, 1095 and 1156 bp encoding XETs, named LcXET1, LcXET2 and LcXET3, respectively, were isolated from expanding fruit using RT-PCR and RACE-PCR (rapid amplification of cDNA ends) methods. Northern blotting analysis showed that LcXET1 mRNA accumulation occurred much earlier in aril tissues at 59 days after anthesis (DAA) than in pericarp tissues at 73 DAA in ‘Nuomici’. However, it appeared at almost the same time (66 DAA) in pericarp and aril tissues in ‘Huaizhi’, which suggested that differential accumulation of LcXET1 in pericarp and aril tissues in ‘Nuomici’ and ‘Huaizhi’ was closely associated with fruit cracking. LcXET2 mRNA accumulation could be detected in pericarp and aril tissues throughout fruit development but exhibited a differential accumulation pattern between pericarp and aril tissues. In the aril of ‘Nuomici’, intensive signal bands were detectable at 59−73 DAA in rapidly expanding fruits of ‘Nuomici’ but only weak bands could be found in the pericarp tissues. In contrast, moderate signal bands were detectable both in pericarp and aril tissues of ‘Huaizhi’ fruits. Furthermore, LcXET3 showed constitutive expression in both pericarp and aril tissues of developing ‘Nuomici’ and ‘Huaizhi’ litchi fruit. In addition, differential expression patterns of three XETs genes were observed in different tissues of litchi, with only LcXET1 being fruit-specific. To further address the role of LcXET in fruit cracking, α-naphthalene acetic acid (NAA) was used to treat ‘Nuomoci’ to reduce fruit cracking. Enhanced LcXET1 mRNA accumulation appeared in pericarp while LcXET2 and LcXET3 mRNA accumulation enhanced in aril tissues in the NAA-treated fruits. Thus, LcXET1 is more likely to play a role in reducing litchi fruit cracking than LcXET2 and LcXET3.

Fatty acid and carotenoid composition of gac (Momordica cochinchinensis Spreng) fruit.

In this study, we analyzed fatty acid and carotenoid composition of fruit tissues, including seed (which are surrounded by a bright red, oily aril) of Momordica cochinchinensis Spreng, known as gac in Vietnam. Carotenoid content was analyzed by reversed-phase HPLC, using a C(30) column and a method separating cis- and trans-isomers of the major carotenoids in this fruit. Mean values obtained in aril tissues were 1342 microg trans-, 204 microg cis-, and 2227 microg total lycopene; 597 microg trans-, 39 microg cis-, and 718 microg total beta-carotene; and 107 microg alpha-carotene/g FW. Mesocarp contained 11 microg trans-, 5 microg cis-beta-carotene/g FW, trace amounts of alpha-carotene, and no lycopene. Gac aril contained 22% fatty acids by weight, composed of 32% oleic, 29% palmitic, and 28% linoleic acids. Seeds contained primarily stearic acid (60.5%), smaller amounts of linoleic (20%), oleic (9%), and palmitic (5-6%) acids, and trace amounts of arachidic, cis-vaccenic, linolenic, and palmitoleic, eicosa-11-enoic acids, and eicosa-13-enoic (in one fruit only) acids.

Changes in Longan and Rambutan During Postharvest Storage

Abstract Compositional changes of longan [Euphoria longan (Lour.) Stend] and rambutan (Nephelium lappaceum L.) collected in two seasons were measured during storage at two temperatures. Seasonal variation reflected both preharvest conditions and maturity at harvest. Total sugars and titratable acidity of longan aril showed little change after harvest at 4° and 22°C. Sucrose of rambutan aril increased from 51 mg·g−1 to 76 mg·g−1 when fruit were stored at 12°, and no change occurred when stored at 22°. Titratable acidity, 20.8 meq·g−1 at harvest in rambutan aril, first declined and then increased at both storage regimes. Succinic acid was found in rambutan aril only at harvest and declined rapidly to an undetectable level. No malic acid was detected in rambutan. A high level of citric acid (≈175 meq·g1) was maintained during storage. The organic acids in longan aril were succinic, malic, and citric acids, present in a ratio of 10:5:1. Ascorbic acid content declined in aril tissue of both longan and rambutan during storage. Total phenols showed little change in either fruit during storage. Except for the changes noted, there were only minor compositional changes in longan fruit stored for 35 days at 4° and rambutan stored for 20 days at 12°.

Changes in the sweet proteins (thaumatins) in thaumatococcus danielli fruits during development

The thaumatin content (forms TO, TI and TII) of fruits from Thaumatococcus danielli at various stages of maturation were examined. The amounts of all three forms of sweet protein increased during maturation to reach a total of about 50 mg/g in mature aril tissue in fruits from both the Ashanti and Kadjebe regions of Ghana. TO was a minor form in fruits at all stages of development from both regions. The major regional difference was that TII was absent from the Kadjebe fruits; however, the total level of sweet proteins was maintained by increased levels of TO and TI. Structural and immunological comparisons of the three thaumatin forms showed that TO is closely related to the other two forms which are known to differ at only five positions in their primary structure.

Litchi Growth and Compositional Changes during Fruit Development

Abstract The changes in litchi (Litchi chinensis Sonn.) growth and composition were studied in 4 cultivars; ‘Groff’ in Hawaii, and ‘Shui Dong’, ‘Gui Wei’, and ‘Mei selection’ in Guangdong, China. Fruit and aril growth showed a sigmoidal pattern while skin growth was slower and more linear. Aborted seeds in Groff and Gui Wei ceased growth early in the log growth phase. Normal seeded cultivars showed seed growth paralleling skin growth. Skin chlorophyll began to decrease logarithmically soon after the start of fruit growth increase, with anthocyanin production beginning about halfway through the growth period. During the rapid growth period, due principally to an increase in aril tissue, there was an increase in total sugars from 3% to 16%. The cultivars showed slightly different ratios of the 3 sugars identified: sucrose, glucose, and fructose. Titratable acidity was due mainly to succinic and malic acid. This acidity decreased over 2 weeks in the middle of the fruit growth period from 65 meq/100 g to 15 meq/100 g. Succinic acid decreased in the same period from about 350 meq/100 g to 0.4 meq/100 g and remained low for the remaining 40 days of development. Malic acid declined from 75 meq/100 g to 12 meq/100 g, and citric acid remained constant at around 3 meq/100 g. A major portion of the decline in succinic acid was due to dilution. Total phenols were low throughout the growth of the fruit. Mineral uptake into the fruit paralleled fruit growth, with potassium being the major cation.

Dispersal of Stemmadenia donnell-smithii (Apocynaceae) by Birds

The dispersal ecology of Stemmadenia donnell-smithii was studied in the tropical dry forest zone of northwestern Costa Rica. Fruit was most abundant late in the dry season and was eaten by 22 species of birds, many of which are primarily insectivorous. Stomach-content analyses substantiated our observations. Total crop size per tree and rate of fruit opening were greatest in pasture-edge trees and smallest in forest trees. Rates and percent of seed germination were highest for seeds from which the surrounding aril was removed, scarified seeds, and seeds which had passed through the digestive tract of a bird. The mean compositions of the fruit tissues were, aril: 7.9% ash, 63.9% lipid, 10.9% protein, 16.8% carbohydrate; seed: 3.4% ash, 31.4% lipid, 10.9% protein, 54.2% carbohydrate; husk: 17.0% ash, 24.0% lipid, 11.2% protein, 47.6% carbohydrate. The foraging behavior of birds taking S. donnell-smithii included hovering, and perching and reaching. Rates of pulp utilization in each habitat were relatively constant; all pulp plus seeds were removed in only a few hours. Calculations of daily energy expenditures suggest that Stemmadenia may provide up to 25 percent of the total energy requirement of individuals of several bird species. Interspecific displacements of birds at fruit were rare. Characteristics of S. donnell-smithii that enhance dispersal include peak fruit availability in dry season, slow rate of opening, seed protection until maturation by husk, bright color of arils, relative accessibility and ease of separation of seed from husk and aril from seed, and high nutritive value of aril. Energetically the plant expends the most calories for protection (husk), followed by expenditures for germination (seed) and dispersal (aril). However, on a calorieper-gram, ash-free, dry-weight basis, the plant puts the greatest amount of energy into aril for dispersal, followed by seed for germination, and then husk for protection. Percent nutrient composition and caloric content of seeds and husk were relatively uniform, whereas lipid, protein, and caloric content of aril tissue varied among samples from different fruits, habitats, and years. This variation may be important in allowing the plant to maintain protection and seed quality while maximizing seed production under varying environmental conditions.