Accumulation Of Dehydrins Research Articles

Seedling survival under drought differs between an annual (Hordeum vulgare) and a perennial grass (Dactylis glomerata).

• In semiarid areas, populations of cereal crop plants can be reduced by severe drought occurring during the vegetative stage, leading to subsequent serious yield reduction. This study aimed to analyse and compare survival and dehydration tolerance in two contrasting barley (Hordeum vulgare) cultivars (cvs) and in a drought resistant perennial grass, cocksfoot (Dactylis glomerata). • In pot experiments, seedlings were subjected to intensifying droughts for analysis of adaptive responses and survival following a range of final soil water potentials (SWP). • Survival rates were 100% in cocksfoot and 32% in the drought resistant barley cv. Tadmor at a SWP of -2.5MPa. In cocksfoot, lamina water potentials decreased earlier and water content in enclosed leaf bases stabilized at low SWP. This strategy of dehydration tolerance was associated with high survival. • At moderate water deficit, barley cv. Tadmor exhibited a 5-fold greater osmotic adjustment in lamina, lower senescence and higher accumulation of dehydrins in enclosed leaf bases than the drought sensitive cv. Plaisant. However, under severe drought, water content in enclosed leaf bases declined constantly and was associated with similar mortality in both cvs. Dehydration tolerance was low in barley and not correlated with dehydrin accumulation or resistance to moderate drought.

Dehydrin Expression and Drought Tolerance in Seven Wheat Cultivars

The winter wheat (Triticum aestivum L.) producing region of the U.S. Pacific Northwest (PNW) is subject to periods of water deficit during sowing and grain filling. Improving the genetic adaptation of wheat to drought stress represents one of the main objectives of regional breeding programs. One biochemical response to dehydrative stress is the accumulation of a family of proteins called dehydrins, which are believed to protect membranes and macromolecules against denaturation. Although previous studies demonstrated the accumulation of dehydrins in drought-stressed wheat, little was known about the relation of dehydrin expression to acquisition of drought tolerance in specific varieties adapted to the PNW. We characterized dehydrin accumulation during the exposure of seven cultivars ('Connie', 'Gene', 'TAM105', 'Rod', 'Hiller', 'Rhode', and 'Stephens') to progressive drought stress in four separate experiments. The objective was to identify differences in the nature or timing of dehydrin expression in these cultivars and to learn whether dehydrin expression was associated with the acquisition of stress tolerance during seedling development. Expression of a 24-kDa dehydrin was observed in Connie, TAM105, and Gene after 4 d of stress and at subsequent sampling dates while no dehydrins were detected in nonstress control plants. Dehydrin expression was significantly delayed in the remaining cultivars. The presence of this dehydrin was related to acquisition of drought tolerance characterized by a greater maintenance of shoot dry matter production in Connie, TAM105, and Gene. Although the role of these proteins remains unknown, their association with stress tolerance suggests that dehydrins might be used to improve the adaptation to drought.

Dehydrin Expression and Drought Tolerance in Seven Wheat Cultivars

The winter wheat (Triticum aestivum L.) producing region of the U.S. Pacific Northwest (PNW) is subject to periods of water deficit during sowing and grain filling. Improving the genetic adaptation of wheat to drought stress represents one of the main objectives of regional breeding programs. One biochemical response to dehydrative stress is the accumulation of a family of proteins called dehydrins, which are believed to protect membranes and macromolecules against denaturation. Although previous studies demonstrated the accumulation of dehydrins in drought-stressed wheat, little was known about the relation of dehydrin expression to acquisition of drought tolerance in specific varieties adapted to the PNW. We characterized dehydrin accumulation during the exposure of seven cultivars (‘Connie’, ‘Gene’, ‘TAM105’, ‘Rod’, ‘Hiller’, ‘Rhode’, and ‘Stephens’) to progressive drought stress in four separate experiments. The objective was to identify differences in the nature or timing of dehydrin expression in these cultivars and to learn whether dehydrin expression was associated with the acquisition of stress tolerance during seedling development. Expression of a 24-kDa dehydrin was observed in Connie, TAM105, and Gene after 4 d of stress and at subsequent sampling dates while no dehydrins were detected in nonstress control plants. Dehydrin expression was significantly delayed in the remaining cultivars. The presence of this dehydrin was related to acquisition of drought tolerance characterized by a greater maintenance of shoot dry matter production in Connie, TAM105, and Gene. Although the role of these proteins remains unknown, their association with stress tolerance suggests that dehydrins might be used to improve the adaptation to drought.

Drought survival, summer dormancy and dehydrin accumulation in contrasting cultivars of Dactylis glomerata.

To study survival under prolonged and severe drought in the perennial grass Dactylis glomerata we compared dormant, resistant and sensitive cultivars (cvs.) in both field and glasshouse experiments. Water status, membrane stability and expression of dehydrins were assessed in the immature leaf bases, which are the last surviving organs. Analysis of leaf elongation and senescence of aerial tissues showed that dormancy was exhibited by the potentially dormant cultivar (cv.) only in the field. This cultivar exhibited a high survival rate, similar levels of dehydration and expression of a low-molecular weight (22-24 kDa) dehydrin in both drought and irrigated plants, whether fully dormant or not. At the same level of soil water deficit, there were no differences between the non-dormant drought resistant and drought sensitive cultivars in plant water status and membrane stability. However, the accumulation of dehydrins as drought progressed was markedly different between these cultivars and was associated with their contrasting survival. The possible role of the major low-molecular dehydrins in maintenance of cell integrity under dehydration is discussed with reference to both summer dormancy and survival under severe drought.

Drying rate and dehydrin synthesis associated with abscisic acid-induced dehydration tolerance in Spathoglottis plicata orchidaceae protocorms.

Dehydration tolerance of in vitro orchid protocorms was investigated under controlled drying conditions and after abscisic acid (ABA) pretreatment. Protocorms were obtained by germinating seeds on Murashige and Skoog (MS) medium containing 10% (v/v) coconut water, 2% (w/v) sucrose and 0.8% (w/v) agar, and were dehydrated in relative humidities (RH) ranging from 7% to 93% at 25 degrees C. The critical water content of dehydration tolerance was determined, using the electrolyte leakage method. Drying rate affected the critical water content. Slow drying under high RH conditions achieved the greatest tolerance to dehydration. ABA pretreatment decreased the drying rate of protocorms, and increased dehydration tolerance. Improved tolerance to dehydration after ABA treatment was correlated with the effect of ABA on drying rate of protocorms. When critical water content of protocorms dried under different RH was plotted as a function of actual drying rate, no significant difference in tolerance to dehydration was observed between ABA-treated and control protocorms. ABA pretreatment and dehydration of orchid protocorms induced the synthesis of dehydrin, especially under the slow drying conditions. ABA pretreatment also promoted dry matter accumulation such as carbohydrates and soluble proteins and increased the concentration of K(+) and Na(+) ions in protocorms. The ABA-induced decrease in drying rate was correlated with lower osmotic potential, the enhanced maturity of protocorms and the accumulation of dehydrin in protocorms during pretreatment.

Accumulation of soluble sugars, heat-stable proteins and dehydrins in cryopreservation of protocorm-like bodies of Dendrobium candidumby the air-drying method

Summary Protocorm-like bodies (PLBs) of Dendrobium candidum were successfully cryopreserved by the air-drying method. The optimal water content before freezing seemed to be at the range of 0.1 g H 2 O/g DW (11 % on fresh weight basis) to 0.5 g H 2 O/g DW (33 % on fresh weight basis). Changes in soluble sugars, heat-stable proteins and dehydrins during desiccation of PLBs were analyzed. Extensive accumulation of soluble sugars was observed at water content of about 7.2 g H 2 O/g DW (after 24 h desiccation), and the sugars content did not increase further during the following desiccation. The amount of heat-stable protein increased significantly when water content decreased to 1.0 g H 2 O/g DW (after approximately 66 h desiccation). Results from immunological detection showed that two bands of the heat-stable proteins with respective molecular masses of 28.7 and 34.3 kDa were dehydrins which appeared when water content dropped to 1.0 g H 2 O/g DW. Therefore, it seemed that accumulation of dehydrins happened later than that of soluble sugars. Interestingly, exogenous ABA treatment of PLBs before desiccation could also induce the accumulation of soluble sugars, heat-stable proteins and dehydrins. The possible roles of these substances in the acquisition of dehydration and freezing tolerance were discussed.

Accumulation of dehydrins and ABA-inducible proteins in wheat seedlings during low-temperature acclimation

Using one-dimensional SDS-PAGE and immunochemical methods, we detected the presence and estimated the content of dehydrins and ABA-inducible (RAB) polypeptides in etiolated seedlings of four spring and three winter wheat (Triticum aestivum L.) cultivars differing in frost hardiness. We hardened three-day-old seedlings at 4°C for nine days or grew them at 22°C for a day (control seedlings). We established that heat-stable cold-regulated (COR) polypeptides with mol wts of 209, 196, 169, 66, 50, and 41 kD, which are characteristic of hardened wheat seedlings, were homologous to polypeptides from a dehydrin family and polypeptides with mol wts of 209, 196, 66, 50, and 41 kD were immunologically related to RAB-proteins. We supposed that these COR polypeptides were involved in the prevention of local protein dehydration and denaturation during hypothermia. Analysis of the relative content of COR proteins revealed a close correlation between the cultivar frost hardiness and the concentration of these proteins. It seems evident that different accumulation of dehydrins and RAB polypeptides in different cultivars of a single species is one of the causes for different plant frost hardiness.

Wheat dehydrin accumulation in response to drought stress during anthesis.

The winter wheat (Triticum aestivum L.) producing region of the US Pacific Northwest (PNW) is often subject to water deficits at sowing and during grain filling. Improved genetic adaptation of wheat cultivars to drought stress is one objective of breeding efforts in the region. Consequently, there is interest in identifying molecular markers associated with drought tolerance. Dehydrins, a family of proteins that accumulate in response to dehydrative stress, may provide a suitable marker for use in breeding programs. Seven cultivars (Connie, Gene, TAM105, Rod, Hiller, Rhode and Stephens) were evaluated in two experiments in which dehydrin accumulation and their association to stress tolerance during grain filling were characterized during progressive drought stress. A24-kDa dehydrin was present in leaves at each sampling date in all seven cultivars. Quantitative differences in accumulation of this protein were observed between cultivars on the third sampling date (4 d of stress). This differential accumulation was associated with stress tolerance characterized by a lower yield reduction and a lowered rate of decrease in leaf water potential in Connie, TAM105 and Gene. In contrast to leaves, an increased number of dehydrins were observed in grains under stress and non-stress treatments. Despite the number of dehydrins detected, there was no apparent association between drought stress and dehydrin expression in grains. Although the specific role of these proteins remains unknown, their association with stress tolerance suggests that dehydrins have utility in improving adaptation to drought and as markers for drought tolerance.

Accumulation and disappearance of dehydrins and sugars depending on freezing tolerance of winter wheat plants at different developmental phases

Several heat-stable dehydrins with mol. wts of 209, 196, 66, 50 and 41 kD characteristic of hardened winter wheat ( Triticum aestivum L.) plants were detected by PAGE and Western blotting. These proteins together with sugars were accumulated under field conditions during low temperature adaptation and disappeared during spring. Their content depended on developmental phase and was connected with plant winter tolerance. Seemingly, more tolerant winter wheat plants have more effective mechanism of additive action of these protecting compounds.

Effect of cold and drought stress on blueberry dehydrin accumulation

SummaryDehydrins are a group of plant proteins which respond to any type of stress that causes dehydration at the cellular level, such as cold and drought stress. Previously, three dehydrins of 65, 60, and 14.kDa were identified as the predominant proteins present in cold acclimated blueberry (Vaccinium corymbosumLinn.) floral buds. Levels were shown to increase with cold acclimation and decrease with deacclimation and resumption of growth. In the present study, to determine if dehydrins are induced in other organs in response to low temperature treatment (48C) and in response to drought, accumulation of dehydrins was examined in leaves, stems, and roots of two cultivars and one wild selection (a V. corymbosum cultivar, a V. ashei Reade cultivar, and a V. darrowi Camp selection) of blueberry by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting. Cold treatment involved placing plants in a cold room maintained at 48C for five weeks; drought stress was imposed by withholding water from potted, greenhouse-grown plants for 34.d. Relative water content (RWC) of shoots was determined periodically throughout the drought treatment. Dehydrins accumulated with both cold and drought stress but their molecular masses varied depending upon blueberry species. Dehydrins accumulated to higher levels in stems and roots than in leaves with cold stress and to higher levels in stems than in either roots or leaves with drought stress. Furthermore, cold treatment combined with dark treatment induced higher levels of dehydrins than cold treatment combined with a 10.h light/14.h dark photoperiod, suggesting that dehydrins may be responsive to changes in photoperiod as well. In the cold-stress experiment, the level of dehydrin accumulation was correlated with expected level of plant cold hardiness in the three genotypes. In the drought stress experiment, dehydrins accumulated prior to significant changes in RWC, and dehydrin levels did not appear to be closely correlated with RWC either among or within genotypes.

Drought survival and dehydration tolerance in Dactylis glomerata and Poa bulbosa

To analyse the contribution of dormancy and dehydration tolerance to drought survival of perennial grasses, we compared Poa bulbosa L., which is classified as a resurrection plant, with one of the most drought resistant cultivars of MediterraneanDactylis glomerata L. Comparing periods when dormancy was induced in Poa (summer) and not induced (winter), we aimed to ascertain the presence of differential plant responses between dormancy and dehydration tolerance and to characterise water status, sugar and dehydrin accumulation in surviving organs of Poa and Dactylis, in relation to their ability to survive intense drought. Irrespective of the dormancy status of Poa, the bulbs of this species had a final water content lower than 10% and survived an extreme drought. This could be associated with the accumulation of sucrose and the expression of a high number (>10) of dehydrins that peaked when the water content of the bulbs fell below 50%, whether this dehydration was due to dormancy induction or increasing soil water deficit. The independence of dormancy to dehydration tolerance was reinforced by the expression of a specific dehydrin (approx. 28 kDa) found only in irrigated, but dormant, tissues of Poa. The Dactylis exhibited contrasting survival between experiments (46 and 0% after a summer and winter drought, respectively). The mortality was associated with a significantly higher rate of decrease of the membrane stability of leaf bases of Dactylis in winter and with barely detectable amounts of sucrose contents in droughted roots. However, neither the water-soluble carbohydrate concentration in leaf bases nor the overall accumulation of dehydrins could be related to the contrasting survival of this Dactylis between the two seasons. Since in seeds of Poa and Dactylis, the accumulation of dehydrins was comparable with that found in droughted aerial tissues of the same species, the expression of these proteins must interact with other mechanisms to confer dehydration tolerance.

Stress-induced accumulation and tissue-specific localization of dehydrins in Arabidopsis thaliana.

Stress-induced accumulation of five (COR47, LTI29, ERD14, LTI30 and RAB18) and tissue localization of four (LTI29, ERD14, LTI30 and RAB18) dehydrins in Arabidopsis were characterized immunologically with protein-specific antibodies. The five dehydrins exhibited clear differences in their accumulation patterns in response to low temperature, ABA and salinity. ERD14 accumulated in unstressed plants, although the protein level was up-regulated by ABA, salinity and low temperature. LTI29 mainly accumulated in response to low temperature, but was also found in ABA- and salt-treated plants. LTI30 and COR47 accumulated primarily in response to low temperature, whereas RAB18 was only found in ABA-treated plants and was the only dehydrin in this study that accumulated in dry seeds. Immunohistochemical localization of LTI29, ERD14 and RAB18 demonstrated tissue and cell type specificity in unstressed plants. ERD14 was present in the vascular tissue and bordering parenchymal cells, LTI29 and ERD14 accumulated in the root tip, and RAB18 was localized to stomatal guard cells. LTI30 was not detected in unstressed plants. The localization of LTI29, ERD14 and RAB18 in stress-treated plants was not restricted to certain tissues or cell types. Instead these proteins accumulated in most cells, although cells within and surrounding the vascular tissue showed more intense staining. LTI30 accumulated primarily in vascular tissue and anthers of cold-treated plants. This study supports a physiological function for dehydrins in certain plant cells during optimal growth conditions and in most cell types during ABA or cold treatment. The differences in stress specificity and spatial distribution of dehydrins in Arabidopsis suggest a functional specialization for the members of this protein family.

Survival strategies under extreme and complex environmental conditions: The aquatic resurrection plant Chamaegigas intrepidus

Chamaegigas intrepidus D inter is a tiny poikilohydric member of the Scrophulariaceae growing endemically in ephemeral rock pools on granite outcrops in Central Namibia. Habitat conditions are characterised by (1) frequent and fast desiccation and rehydration during the rainy summer season, (2) complete dehydration during the dry winter season lasting up to 11 months, (3) intensive solar irradiation and high temperatures during the dry season, (4) diurnal oscillations of pH in the pool water up to 6 units, (5) extreme nutrient deficiencies, especially nitrogen. Anatomical, biochemical and physiological adaptations to this complex of extreme environmental conditions are discussed such as contractive xylem, accumulation of abscisic acid, dehydrins and carbohydrates during desiccation, and the role of amino acids, ammonium, urea and urease for nitrogen nutrition.

602 Sequencing and Characterizing Blueberry (Vaccinium section Cyanococcus) Dehydrins

The blueberry industry experiences significant losses every year due to environmental factors with a dehydrative component, such as drought and freezing stress. In a recent survey of blueberry research and extension scientists in the United States, lack of cold hardiness and susceptibility to spring frosts were identified as the most important genetic limitations of current cultivars. For these reasons, cloning and characterization of expression of dehydration-responsive genes (dehydrins) have been ongoing in our laboratory. To date, one full-length (2.0 kb bbdhn1 gene) and four partial-length dehydrin cDNAs have been cloned and sequenced. Very high homology at the DNA and protein levels were found among the blueberry dehydrin clones, particularly at the 3' ends. From DNA blots, it appears that blueberry dehydrins are encoded by about three genes with high homology to the full-length 2.0 kb bbdhn1 cDNA clone and a few other less related genes. The 2.0 kb bbdhn1 gene was mapped in a blueberry population segregating for cold hardiness and chilling requirement. Expression studies indicated that dehydrins are induced by cold and drought stress. In general, dehydrins were induced in all organs examined in response to cold stress, including floral buds, leaves, stems, and roots. Under drought conditions, dehydrins were induced primarily in stems and their levels declined in roots. Some of the induced dehydrins were the same for drought and cold stress, whereas others were unique to a given stress. Levels of dehydrin accumulation correlated positively with cold hardiness; however, levels of dehydrins did not correspond precisely to the degree of drought avoidance.

A 25-kDa dehydrin associated with genotype- and age-dependent leaf freezing-tolerance in Rhododendron: a genetic marker for cold hardiness?

Dehydrins are plant proteins that may play a critical role in stabilizing cell functions during freezing and other dehydrative stresses. This study examines whether dehydrin expression in leaves is associated with varying levels of freezing-tolerance among F2 segregants, species, and cultivars of evergreen Rhododendron. Experiments were also conducted to determine whether physiological and chronological aging affects freezing-tolerance and dehydrin accumulation in Rhododendron leaf tissues. Our results indicate that in cold-acclimated F2 populations, levels of a 25-kDa dehydrin were closely associated with differences in leaf freezing-tolerance (LFT) among segregants. Studies of wild and cultivated plants indicated that LFT increased with both chronological age and developmental phase-change (juvenile to mature plants) and that this trend was accompanied by increased accumulation of the 25-kDa dehydrin. It is suggested that presence or absence of the 25-kDa dehydrin could serve as a genetic marker to distinguish between super cold-hardy and less cold-hardy rhododendron genotypes. Similarly, the relative level of this protein within a genotype can serve as a physiological indicator of freezing-tolerance status under a range of phenological (acclimation) or developmental (age) conditions.

Temporal accumulation and ultrastructural localization of dehydrins in Zea mays

Immunolocalization using polyclonal antibodies raised against a conserved dehydrin amino acid sequence was used to establish the temporal and spatial patterns of dehydrin accumulation in embryo tissue of Zea mays L. (var. Ohio 43) kernels imbibed in the presence of abscisic acid. The temporal pattern of accumulation indicated an increase in dehydrins over time (particularly between 15 and 30 h) and with maximum levels detected 48 h after the onset of imbibition. Dehydrins were first evident, and also the most concentrated, in the cytosol throughout the accumulation period suggesting that the primary function of dehydrins involves the cytosol and the structures contained therein. Only after an accumulation of dehydrins in the cytosol was there an increase in the abundance of nuclear dehydrins. In addition, dehydrins were also observed in association with the proteinaceous matrix of protein bodies and membranes of protein and lipid bodies; these findings have not been reported previously. The observed localization at a number of sites indicates that the specific biochemical roles of dehydrins are likely to be diverse.

Temporal accumulation and ultrastructural localization of dehydrins in Zea mays

Temporal accumulation and ultrastructural localization of dehydrins in Zea mays

Water-stress response in aspen ( Populus tremula): Differential accumulation of dehydrin, sucrose synthase, GAPDH homologues, and soluble sugars

Summary In a previous study we identified a novel 66-kD boiling-stable protein (BspA) that accumulates in cultured shoots of aspen ( Populus tremula L.) in response to gradual water stress and ABA application, as well as to osmotic and cold stresses (Altman et al., 1996; Pelah et al., 1995). BspA was found to be the major heat-stable water stress-responsive protein in aspen. Here, the expression of other water-stress responsive proteins — DSP 16 (dehydrin), cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and sucrose synthase — was studied in aspen roots and shoots. These proteins were identified immunologically using polyclonal antibodies isolated from the resurrection plant Craterostigma plantagineum . A 43-kD homologue and a 31-kD homologue of dehydrin were found to accumulate in roots and shoots of aspen after water stress in a tissue specific manner. Shoots and roots of intact plantlets subjected to ABA application accumulated a 33-kD dehydrin homologue. A sucrose synthase homologue (90 kD) accumulated in water-stressed shoots and was constitutively present at high levels in control and water-stressed roots harvested from intact plandets. GAPDH, a key enzyme in the glycolysis and gluconeogenesis pathways, exhibited some accumulation in shoots in response to water stress. Sugar analysis revealed that water stress results in increased sucrose and decreased glucose levels in the aspen leaves. The data presented here suggest that the water-stress-response mechanisms present in herbaceous plants are also present in woody plants. Woody plants subjected to water stress accumulate dehydrin-like proteins and specific enzymes such as sucrose synthase and GAPDH, which may play a dominant role in sugar metabolism under these conditions.

Accumulation of a 60-kD Dehydrin Protein in Peach Xylem Tissues and Its Relationship to Cold Acclimation

The seasonal pattern of dehydrin accumulation was characterized during cold acclimation and deacclimation in the xylem tissues of genetically related (sibling) deciduous and evergreen peach (Prunus persica L.). Immunological studies indicate that a 60-kD polypeptide in peach xylem tissues is a dehydrin protein. Comparison of its accumulation pattern with seasonal fluctuations in cold hardiness indicate that dehydrin accumulated to high levels during the peak of cold acclimation. However, its accumulation was only weakly associated with cold hardiness during early stages of cold acclimation and during deacclimation. Our results indicate that factors related to supercooling rather than dehydrin accumulation may be primarily responsible for determining levels of cold hardiness during transition periods.

Development of Desiccation Tolerance during Embryogenesis in Rice (Oryza sativa) and Wild Rice (Zizania palustris) (Dehydrin Expression, Abscisic Acid Content, and Sucrose Accumulation).

The ability of seeds to withstand desiccation develops during embryogenesis and differs considerably among species. Paddy rice (Oryza sativa L.) grains readily survive dehydration to as low as 2% water content, whereas North American wild rice (Zizania palustris var interior [Fasset] Dore) grains are not tolerant of water contents below 6% and are sensitive to drying and imbibition conditions. During embryogenesis, dehydrin proteins, abscisic acid (ABA), and saccharides are synthesized, and all have been implicated in the development of desiccation tolerance. We examined the accumulation patterns of dehydrin protein, ABA, and soluble saccharides (sucrose and oligosaccharides) of rice embryos and wild rice axes in relation to the development of desiccation tolerance during embryogenesis. Dehydrin protein was detected immunologically with an antibody raised against a conserved dehydrin amino acid sequence. Both rice and wild rice embryos accumulated a 21-kD dehydrin protein during development, and an immunologically related 38-kD protein accumulated similarly in rice. Dehydrin protein synthesis was detected before desiccation tolerance had developed in both rice embryos and wild rice axes. However, the major accumulation of dehydrin occurred after most seeds of both species had become desiccation tolerant. ABA accumulated in wild rice axes to about twice the amount present in rice embryos. There were no obvious relationships between ABA and the temporal expression patterns of dehydrin protein in either rice or wild rice. Wild rice axes accumulated about twice as much sucrose as rice embryos. Oligosaccharides were present at only about one-tenth of the maximum sucrose concentrations in both rice and wild rice. We conclude that the desiccation sensitivity displayed by wild rice grains is not due to an inability to synthesize dehydrin proteins, ABA, or soluble carbohydrates.