Effects of Environment on the Metabolism and Germination of Crested Wheatgrass Seeds

Wilson, A. D.; Nelson, Jack R.; Goebel, Carl J.

doi:10.2307/3896222

Cited by 14 publications

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“…After periods of severe drought, crested wheatgrass seeds resume synthesis of both ATP (19) and a-amylase (Fig. 5).…”

Section: Discussionmentioning

confidence: 99%

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Amylase Synthesis and Stability in Crested Wheatgrass Seeds at Low Water Potentials

Wilson

1971

Plant Physiol.

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Drying of seeds of Agropyron desertorum (Fisch. ex Link) Schult. did not result in breakdown of a-amylase nor impair the ability of seeds to resume its synthesis when moistened again. p-Amylase activity did not change during 5 days of germination at a water potential of 0 atmosphere nor during 40 days of incubation at -40 atmospheres. Seeds synthesized cx-amylase at 0, -20, and -40 atmospheres, but not at -60 atmospheres. At 0 and -20 atmospheres, the log of a-amylase activity was linearly related to hastening of germination. But at -40 atmospheres, seeds synthesized a-amylase during a time when there was little hastening of germination. Thu, it appears that other biochemical reactions are less dronghttolerant than synthesis of a-amylase. It is concluded that inhibition of a-amylase synthesis is not a controlling factor in the germination of these seeds at low water potentials.The objective of this study was to determine if inhibition of a-amylase synthesis might be a mechanism by which drought retards or prevents the germination of crested wheatgrass seeds. The hypothesis motivating this work is that seeds differing in their ability to germinate at low water potentials also differ in their ability to carry on drought-intolerant metabolic reactions. I selected a-amylase for study because its synthesis in barley half-seeds is intolerant to drought (6).Experiments concerned with the effects of chemical inhibitors support the view that a-amylase synthesis and starch breakdown are essential steps in germination. For example, abscisic acid inhibits growth response and a-amylase synthesis in intact barley seeds (9); benzyladenine delays the production of amylase and the concomitant breakdown of starch in pea seeds (15); salinity decreases germination, early seedling growth, release of reducing sugars, and synthesis of amylase in wheat (12).Swain and Dekker (17) have concluded from enzyme studies that a-amylase action is the first step in the hydrolytic breakdown of starch in pea cotyledons. Murata et al. (11) may account for much smaller amounts of starch breakdown, as compared to the amounts hydrolyzed by a-amylase.Cell enlargement and, consequently, seed germination are dependent on the availability of substrates for metabolism and of solutes for maintaining positive turgor potentials. Chen and Varner (3) have concluded that starch breakdown, synthesis of sucrose, and translocation of sucrose to cells of the embryo are essential processes in the germination of Avena fatua. They suggested that lack of sucrose synthesis, rather than of starch breakdown, is the explanation for dormancy in this species. It seems probable that one or more of these processes may be related to the germination of seeds at low water potentials.This paper reports (a) the stability of a-amylase during drought, (b) the resumption of a-amylase synthesis after drought, and (c) the effects of constant water potentials on the relationship between synthesis of a-amylase and hastening of germination. Crested wheatgrass, the test species, is ...

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“…After periods of severe drought, crested wheatgrass seeds resume synthesis of both ATP (19) and a-amylase (Fig. 5).…”

Section: Discussionmentioning

confidence: 99%

“…Crested wheatgrass, the test species, is adapted for germination and establishment on semiarid lands and is often exposed to severe drought and fluctuating moisture conditions (19).…”

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confidence: 99%

Amylase Synthesis and Stability in Crested Wheatgrass Seeds at Low Water Potentials

Wilson

1971

Plant Physiol.

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“…Seeds which remained ungerminated on the control treatment 3 months after sowing in summer had a mean laboratory germination of 15%, which indicated that "weathering" greatly reduced viability (Wilson et al, 1970). Table 2 shows that percentage radicleentry was higher on the winter control than on the spring or summer control, due most likely to low strength and moisture tension of the soil surface in winter (Fig.…”

Section: Seeds Taken By Antsmentioning

confidence: 97%

“…To increase productivity on these areas it would be necessary to establish improved perennial pastures by aerial methods. However, establishment of perennial pasture species from surface-sowing has been disappointing (Campbell, 1968;Nelson et al, 1970;Dowling et al, 1971). Attention has been drawn to the dearth of information explaining the reasons for such disappointing results (Cullen, 1965;McWilliam et al, 1970;Wilson et al, 1970).…”

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confidence: 99%

Factors Causing Losses during the Establishment of Surface-Sown Pastures

Campbell¹,

Swain²

1973

Journal of Range Management

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Seeds of four pasture species were surface-sown in winter, spring, and summer and losses of seeds, seedlings, and plants during germination, radicle-entry, establishment, and survival noted under various treatments. On an unprotected soil surface losses during germination, radicle-entry and establishment were least in winter and greatest in summer. Dead plant cover on the surface reduced losses during germination and radicle-entry in the summer, while sub-irrigation reduced losses during germination in summer and radicle-entry and establishment in spring and summer. Losses during survival were heavy in all seasons, usually because of moisture stress. Other reasons for losses included harvesting of seeds by ants, damage by soil fauna, residual herbicides, and competition from weeds.

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“…Seeds begin metabolism during the early stages of imbibition (Mayer and Poljakoff-Mayber 1982). Wilson et al ( 1970) measured the synthesis of phosphate esters in crested wheatgrass (Agropyron desertorum) seeds at various intervals after planting to evaluate the sensitivity of seeds to environmental changes and their readiness to germinate. Marked increases in ester production were measurable after 4.3 mm of rainfall.…”

Section: °C Soil Surface Temperaturementioning

confidence: 99%

Effects of Pattern and Amount of Simulated Rainfall on Seedling Dynamics of Weeping Lovegrass and Kleingrass¹

Wester¹,

Dahl²,

Cotter

1986

Agronomy Journal

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Range seeding is a common improvement practice for revegetating abandoned cultivated land or following mechanical brush control. However, seeding failure is frequent because of unfavorable moisture and temperature conditions. The objective of this research was to study weeping lovegrass (Eragrostis curvula) and Kleingrass (Panicum coloratum) seedling emergence and survival in response to 16 different patterns and amounts of irrigation at 38, 30 and 24°C soil surface temperatures in a dry sand in a growth room. Watering treatments consisted of different sequences of wet and dry days; each watering day provided 5 mm. Pattern and amount of water affected seedling emergence and survival. Both species required 2 days of water to emerge at 30 and 24°C; there was no emergence at 38°C. Seedlings which emerged soonest within a treatment tended to survive longer than seedlings which emerged later. When treatment moisture was not sufficient to stimulate high emergence, seeds remained viable and emerged later when additional adequate moisture was provided. Field trails were established in a second phase of this research; growth-room results were confirmed under natural and simulated rainfall. These results suggest that rainfall in specific patterns and amounts is important in determining seeding success.

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Effects of Environment on the Metabolism and Germination of Crested Wheatgrass Seeds

Cited by 14 publications

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Amylase Synthesis and Stability in Crested Wheatgrass Seeds at Low Water Potentials

Amylase Synthesis and Stability in Crested Wheatgrass Seeds at Low Water Potentials

Factors Causing Losses during the Establishment of Surface-Sown Pastures

Effects of Pattern and Amount of Simulated Rainfall on Seedling Dynamics of Weeping Lovegrass and Kleingrass¹

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Effects of Environment on the Metabolism and Germination of Crested Wheatgrass Seeds

Cited by 14 publications

References 0 publications

Amylase Synthesis and Stability in Crested Wheatgrass Seeds at Low Water Potentials

Amylase Synthesis and Stability in Crested Wheatgrass Seeds at Low Water Potentials

Factors Causing Losses during the Establishment of Surface-Sown Pastures

Effects of Pattern and Amount of Simulated Rainfall on Seedling Dynamics of Weeping Lovegrass and Kleingrass1

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Effects of Pattern and Amount of Simulated Rainfall on Seedling Dynamics of Weeping Lovegrass and Kleingrass¹