Patterns of variation in Ontario wild rice (Zizania Aquatica L.).2. Differential responses of populations to varying cultivation conditions

1988 ◽  
Vol 31 (1-2) ◽  
pp. 23-36 ◽  
Author(s):  
R.L. Counts ◽  
P.F. Lee
Keyword(s):  
Wild Rice ◽  
Cultivation Conditions ◽  
Zizania Aquatica ◽  
Differential Responses

The morphology of grain abscission in Zizania aquatica

1980 ◽  
Vol 58 (21) ◽  
pp. 2269-2273 ◽  
Author(s):  
H. B. Hanten ◽  
G. E. Ahlgren ◽  
J. B. Carlson
Keyword(s):  
Wild Rice ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Embryo Sac ◽  
Middle Lamella ◽  
Abscission Zone ◽  
Rice Grains ◽  
Zizania Aquatica ◽  
Parenchyma Cells ◽  
Anatomical Evidence

The anatomical development of the abscission zone in grains of Zizania aquatica L. was correlated with development of the embryo. The abscission zone is well developed when the embryo sac is mature. Soon after pollination, the first anatomical evidence of abscission appears as plasmolysis of the separation layer parenchyma cells. This is followed by separation of the layers by dissolution of the middle lamella and fragmentation of cell walls. Persistence of intact vascular tissue and presence of a surrounding cone-shaped mass of lignified cells may be involved in abscission of wild rice grains.

A DEVELOPMENTAL STUDY OF WILD RICE, ZIZANIA AQUATICA L.

1960 ◽  
Vol 38 (5) ◽  
pp. 719-741 ◽  
Author(s):  
Cynthia E. Weir ◽  
Hugh M. Dale
Keyword(s):  
Wild Rice ◽  
Embryo Sac ◽  
Developmental Study ◽  
Abscission Layer ◽  
Potential Yield ◽  
Zizania Aquatica ◽  
History Of ◽  
Nuclear Changes ◽  
Well Differentiated ◽  
The Many

The life history of wild rice is traced from the appearance of the first submersed leaves in the spring until the seed of this annual plant is buried at the bottom of a lake in the fall. The characteristics of the three types of leaves are discussed. The change from the simple vegetative apex to the many-tipped, young inflorescence occurs early. Thus the potential yield in rice grains is determined as the tips of the upright leaves reach the surface of the water and before the stem elongates. The inflorescence develops acropetally as does each spikelet. Only at the later stages can the pistillate and staminate spikelets be distinguished. The development of the microspores and the nuclear changes in the embryo sac have been elucidated. In Zizania the embryo development has been found to be a variant of that found in Poa while the endosperm develops chiefly from the outside. A well-differentiated abscission layer develops at the base of each spikelet.

Potential for nitrogen fixation in the rhizosphere and habitat of natural stands of the wild rice Zizania aquatica

1979 ◽  
Vol 57 (11) ◽  
pp. 1285-1291 ◽  
Author(s):  
M. T. Ogan
Keyword(s):  
Nitrogen Fixation ◽  
Water Column ◽  
Acetylene Reduction ◽  
Wild Rice ◽  
Heterotrophic Bacteria ◽  
Nitrogenase Activity ◽  
Early Summer ◽  
Zizania Aquatica ◽  
Natural Stands ◽  
Root Surfaces

The potential for nitrogen fixation in the rhizosphere and habitat of natural stands of Zizania aquatica (L) was studied by the acetylene reduction method. The data obtained suggested that this potential exists in the water column, the rhizosphere soil of the wild rice habitat, and on the root surfaces of the plants.In situ determination of rates of nitrogen fixation in the water column showed low but significant levels only in late spring – early summer and the rate was thought to be dependent on the presence of the blue-green algae Aphanizomenon. Laboratory experimental evidence showed that acetylene reduction by rhizosphere surface soil was attributable to Oscillatoria species while bacteria were more active in the subsurface soil and on the root surfaces. The bacteria-mediated nitrogenase activity was often preceded by a long lag period. The heterotrophic bacteria involved were enumerated, isolated, and characterised and they belong to the genera Azotobacter and Clostridium. Algal components of blooms occurring within the stands of Zizania at various times were identified.

Ecological relationships of wild rice, Zizania aquatica. 7. Sediment nutrient depletion following introduction of wild rice to a shallow boreal lake

1988 ◽  
Vol 66 (2) ◽  
pp. 236-241 ◽  
Author(s):  
T. J. Keenan ◽  
P. F. Lee
Keyword(s):  
Wild Rice ◽  
Paired Comparison ◽  
Dry Weight ◽  
Nutrient Depletion ◽  
Ecological Relationships ◽  
Manganese Zinc ◽  
Northwestern Ontario ◽  
Zizania Aquatica ◽  
Marked Decline ◽  
Growth Changes

A marked decline in wild rice production was observed 5 years after a northwestern Ontario lake was seeded. A paired-comparison t-test detrmined that sediment manganese, zinc, copper, magnesium, and potassium had all declined in concentration, but nitrogen showed the greatest decrease. Discriminant analysis indicated that sediment nitrogen contributed most to a function distinguishing between years. A controlled experiment using several fertilizer formulations also found that addition of nitrogen to sediment from the lake promoted the greatest increase in wild rice growth. Changes in distribution of wild rice and in values of water depth, organic matter, dry weight of other macrophytes, and wild rice density and dry weight indicated that the decrease in sediment nitrogen was probably associated with movement of wild rice straw within the lake.

Ecological relationships of wild rice, Zizania aquatica. 5. Enhancement of wild rice production by Potamogeton robbinsii

1987 ◽  
Vol 65 (7) ◽  
pp. 1433-1438 ◽  
Author(s):  
P. F. Lee
Keyword(s):  
Discriminant Analysis ◽  
Bulk Density ◽  
Wild Rice ◽  
Organic Content ◽  
Loss On Ignition ◽  
Sediment Samples ◽  
Ecological Relationships ◽  
Zizania Aquatica ◽  
Limiting Nutrient ◽  
Clay Sediment

Production of wild rice in a lake with clay sediment was examined inside and outside clumps of Potamogeton robbinsii (L.). Dry weights of wild rice plants were 10–15 times greater inside than outside these clumps. Analyses of variance of sediment samples revealed that values of loss on ignition, phosphorus, manganese, and zinc were higher inside the clumps of P. robbinsii, while values of bulk density, pH, and water depth were higher outside the clumps. Discriminant analysis was able to separate the samples on the basis of the values of phosphorus, manganese, and zinc relative to bulk density, copper, calcium, and depth. Experiments with various fertilizer treatments under controlled conditions determined that the primary limiting nutrient in the sediment outside the P. robbinsii clumps was phosphorus. It was proposed that as Potamogeton robbinsii decayed, it increased the organic content of the clay sediment, thereby lowering the pH and increasing the availability of nutrients.

Ecological relationships of wild rice, Zizania aquatica. 4. Environmental regions within a wild rice lake

1986 ◽  
Vol 64 (9) ◽  
pp. 2037-2044 ◽  
Author(s):  
P. F. Lee
Keyword(s):  
Cluster Analysis ◽  
Discriminant Analysis ◽  
Wild Rice ◽  
Rice Plant ◽  
Plant Competition ◽  
Organic Content ◽  
Ecological Relationships ◽  
Zizania Aquatica ◽  
Low Phosphorus ◽  
Phosphorus Levels

Four environmental regions with similar characteristics were identified within a lake that had been uniformly seeded with wild rice. Q-type cluster analysis was used to identify the environmental regions and discriminant analysis verified their existence. The regions differed from one another in the amount of plant competition and the phosphorus, zinc, and organic content of the sediment. By superimposing weight per wild rice plant categories with the locations of the environmental regions, it was found that the environmental regions were related to wild rice production. Low weights per wild rice plant were due to low phosphorus levels, low organic content of the sediment, or high plant competition values. Only where these variables were at suitable levels were high weights per wild rice plant obtained.

The effect of flooding on wild rice, Zizania aquatica L.

1988 ◽  
Vol 32 (3) ◽  
pp. 283-290 ◽  
Author(s):  
Eva Pip ◽  
Jeffray Stepaniuk
Keyword(s):  
Wild Rice ◽  
Zizania Aquatica

Ecological relationships of wild rice, Zizania aquatica. 8. Classification of sediments

1989 ◽  
Vol 67 (5) ◽  
pp. 1381-1386 ◽  
Author(s):  
W. R. Day ◽  
P. F. Lee
Keyword(s):  
Bulk Density ◽  
Wild Rice ◽  
Dry Weight ◽  
Loss On Ignition ◽  
Ph Values ◽  
High Phosphorus ◽  
Sediment Types ◽  
Zizania Aquatica ◽  
Density Values ◽  
Organic Clay

Cluster and discriminant analysis classified sediments from potential and existing wild rice lakes into three major and three hybrid types. The three major sediment types were described as clay, organic, or flocculent, and the three hybrid types as organic – flocculent, organic – clay, or organic over clay. The major differences among the six sediment types were the percent loss-on-ignition, bulk density, phosphorus, cation, and pH values. Organic sediments were characterized by high phosphorus, cation, and loss-on-ignition values, and lower pH values. Clay sediments had the highest bulk density values, but were low in phosphorus. Flocculent sediments exhibited the lowest bulk density, phosphorus, and cation values, and the highest loss-on-ignition and pH values. The three hybrid sediment types had values for these variables intermediate to their parent types. Flocculent, clay, and organic–flocculent sediment types produced the lowest dry weights of individual wild rice plants. Best production (in terms of dry weight) occurred in organic, organic–clay, and organic over clay sediments that had loss-on-ignition values ranging from 29 to 49%, were slightly acidic (pH values of 5.9 −6.2), and had high phosphorus (> 1.0 g ∙ m−2) and cation values.

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