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Eski 30-10-2008, 08:37   #4
oceanheart
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Giriş Tarihi: 15-02-2008
Şehir: İZMİR-İSTANBUL
Mesajlar: 448
Sn. Tugo,
Aşağıda sucul bitkilerin tohumdan üretimi konusunda ABD üniversitelerinden birisinin bilimsel çalışması var,Hpsinin çevirisini yapmaya zamanım yok ama özetlemek gerekirse özellikle nilüfer tohumlarının belli bir süre soğuk suda bekletilmesi gerekiyor

Storage and Germination of Seeds of Aquatic Plants
W.C. Muenscher

Excerpted from:
Muenscher, W.C. 1936. Storage and germination of seeds of aquatic plants. New York (Cornell University) Agr. Exp. Sta. Bul. 652, pp. 1-17.

Note: This is an excellent early reference for germinating aquatic plants. It is probably difficult to find this reference (1936), so I have abstracted parts of it here.

Information set within “ “ are direct quotes, the remainder is abstracted. Square brackets [ ] indicate additional information, abstracted from the article. Current family/genus/species corrections, indicated by { }, are according to GRIN (USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network) (http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl).

Currently restricted species that are state noxious weeds were not abstracted. They included: Butomus umbellatus [Flowering Rush], Najas minor [{brittle} Naiad], Trapa natans (Water Chestnut).

Donald Stevens, Hamilton, Ontario, Canada


The seeds tested were of 43 species, representing 30 genera in 20 families of aquatic or marsh plants growing wild in New York State and harvested in 1935.

The following seed storage conditions were used:
1. 1. Stored in tap water at 1-3C.
2. 2. Stored in tap water, in diffuse light at room temperature (18 - 20C) but subject to extreme fluctuations between 10-22C.
3. 3. Stored air-dry at 1-3C.
4. 4. Stored air-dry at room temperature.

Germination testing was done after the seeds had been stored approximately 2, 5 and 7 months. “Duplicate lots of 100 seeds were placed in germinators, 2-quart jars filled nearly full with tap water. The jars were placed in diffuse light on a bench in a plant house with approximate day temperature of 18-21C and a night temperature of 13-16C. The germinated seeds were counted and removed at intervals within 2 to 5 days after germination. The earlier cultures were mostly run as long as seeds continued to germinate”


SUMMARY

“The results of germination tests made on seeds of each series after about 2, 5 and 7 months in storage indicate that storage in water at a temperature just above freezing is the best of the treatments applied to insure viability and quick germination in most of the species tested.

With few exceptions, seeds of most of the species would not germinate after 2 to 5 months of storage in water at room temperature. Seeds so treated entered a rest period but they cold be induced to germinate by subsequently chilling them for 30 days. Seeds of Vallisneria [Wild Celery, Eel-grass], Orontium [Golden Club] and Nasturtium [Water Cress] germinated well within 2 months after harvest, without chilling.

The seeds of most species failed to germinate after 2 to 5 months in dry storage at 1-3C or at room temperature. In some species such as those of Orontium, Pelandra [Arum], Vallisneria and Zizania [Wild Rice {northern}], drying the seed killed the embryo. In others, drying prolonged the dormant state of the seed or, largely through changes in the seed coat or pericarp, caused it to enter a long rest period.

…The storage conditions after which the best germination results were obtained approach nearest to the conditions to which sees of aquatic plants are subjected when they are shed naturally, in water at low temperature from late autumn until early spring.

The results of the germination tests here reported lead to the suggestion that seeds of most aquatic plants intended for planting should never be allowed to dry, but should be stored in water just above freezing temperature, until time for planting in the spring. Such treatment should provide a source of viable seed that can be shipped for some distance with the assurance that the seeds will germinate soon after they are planted in a suitable habitat.”


RESULTS

NYMPHAEACEAE
{Nuphar variegata} "Nymphozanthus variegatus (yellow pond lily). Seeds stored in cold water for 7 months gave 43 per cent germination, mostly between 15 to 24 days after the germination test was begun. Seeds stored for 2 to 7 months dry or in water at room temperature, did not germinate even after subsequent chilling or puncturing of the seed coats.”

{Nymphaea odorata subsp. tuberosa} “ Nymphaea tuberosa (white water-lily) seeds gave fair germinations, 16 to 56 per cent, after 2 to 7 months of storage in cold water. Seeds stored dry or in water at room temperature did no germinate evens after subsequent chilling or puncturing of the seed coats… [another lot of seeds] placed in cold storage in water gave 44 per cent germination within 10 days.”


ARACEAE
“Acorus calamus (Sweet Flag) … seeds… were tested after 2, 5, and 7 months of storage in water at 1 - 3C.; 54 per cent germination was obtained from seeds stored for 7 months, but noNe was obtained from seeds stored for a shorter period. Seeds stored in water at room temperature for 7 months did not germinate, but when such seeds were later chilled at 1 - 3C for 30 days, 26 per cent of them germinated within 12 days. No germination was obtained from seeds kept in dry storage even after subsequent chilling in water.”

“Calla palustris. [Calla] Good germination was obtained from seeds which had been in cold storage in water for 5 to 7 months. Seeds stored dry in the laboratory for 7 months gave 27 per cent germination, whereas those stored only 5 months did not germinate. When the seed coats of the dried seeds were cut open, 65 per cent of these seeds germinated within 18 days. Apparently Call seeds can withstand drying for some time but cold storage in water insures a greater viability and quicker and more uniform germination.”

“Orontium aquaticum (Golden Club) seeds germinate soon after they mature, without chilling or drying… When the seeds were harvested, most of them had already fallen into the moist muck at the base of the plants. Germination had already begun in 71 per cent of the seeds when they were gathered. The 29 per cent of ungerminated seeds were used in the germination tests. Of the seeds stored in cold water, when tested ..[after 2, and 5 months].. 88 and 92 per cent, respectively, germinated within 4 days. The seeds stored in water in the laboratory nearly all germinated within 6 days, 86 per cent, and the remainder decayed. None of the dry seeds germinated; all of them decayed soon after they were placed in germinators.”

“Peltandra virginica [Arum] seeds germinated well after 5 to 7 months of cold storage in water. Most of the seeds germinated within 10 to 15 days. Seeds stored at room temperature in water did not germinate but decayed … Drying apparently killed the seeds, since none of them germinated but all soon decayed.”


ALISMACEAE {ALISMATACEAE}
“Alisma plantago-aquatica. [Water Plantain] Seeds stored in cold water for 1, 4, and 6 months gave good germination within 4 to 6 days … If the seeds are not allowed to dry out they do not enter a long rest period. Seeds stored in water at room temperature did not germinate when tested after 2, 5, or 7 months, but 3 per cent of the seeds germinated while in storage, within a month after harvest. This indicates that some of the embryos at least are not dormant and are not prevented from germinated by the mechanical restrictions of the seed coat… when seeds, which had been stored in water at room temperature for 5 months, were transferred to 1-3C for 30 days and then placed on the plant-house bench, 82 per cent germination was obtained within 6 days. In all the tests with dry seeds, only 1 seed germinated. … Seeds stored dry for some time appear to be unable to absorb enough water to permit the embryo to grow unless the seed coat is ruptured… IN seeds which were never permitted to dry out, neither pericarp nor seed coat seemed to offer restrictions to prevent germination. Such seeds… germinate freely without first entering a long rest period as do seeds which have been dried.”

“Sagittaria latifolia. [{Common} Arrow-head] No seeds germinated unless they were first stored in cold water for 5 to 7 months….”

{Sagittaria motevidensis subsp. spongiosa} “Lophotocarpus spongiosus. The seeds failed to germinate after all storage treatments …”


CERATOPHYLLACEAE
“Ceratophyllum demersum (Hornwort) seeds gave good germination after 5 to 7 months of cold storage in water. By cutting a slit in the pericarp after 3 months of cold storage in water, 65 per cent germination was obtained within 7 days. None of the dried seeds germinated, even after subsequent chilling or cutting of the pericarp.”


CRUCIFERAE {BRASSICACEAE]
{Nasturtium officinale} “Nasturtium Nasturtium-aquaticum (WaterCress) seeds gave good germination when tested after all storage treatments…[a second lot of seeds] gave rather low germination after the short cold-storage treatment, either dry or in water. The seeds remain viable for at least 9 months wen stored dry. The seeds germinate best if the germinators are exposed to alternating high and low temperatures.”


CYPERACEAE
{Schoenoplectus acutus} “Scirpus acutus. [{Hardstem} Bulrush] No germination was obtained after any of the storage treatments.”

{Schoenoplectus americanus] “Scirpus americanus [Shore Rush{American Bulrush}] “and {Schoenoplectus tabernaemontani} “Scipus validus [Great Bulrush] Only a few seeds germinated after they had been stored in water. Dried seeds of S. americanus gave even less, 1 to 2 per cent germination, after 5 to 7 months in storage.”

{Eleocharis geniculata} “Eleocharis calva. [Spike Rush] Only 6 per cent germination was obtained from seeds stored in cold water for 7 months. None of the seeds germinated until they had been in the germinator for 40 days or more. Seeds stored dry or in water at room temperature did not germinate.”


ELATINACEAE
“Elatine americana (Waterwort) seeds were stored only in water. A high percentage of germination was obtained after 4 to 6 months in cold storage, but none form the unchilled seeds.”


ERIOCAULACEAE
{Eriocaulon aquaticum} “Eriocaulon septangulare (Pipewort). A high percentage of germination was obtained after 5 to 7 months in cold storage in water. Seeds stored in water in the laboratory did not germinate, but after chilling them for 30 days, 27 per cent germinated. Dried seeds did not germinate even after subsequent storage in water.”


GRAMINEAE {alternate} {POACEAE]
“Glyceria striata.[Manna Grass] Some germination was obtained after 2 months with all storage treatments but best results were obtained after 5 to 7 months of storage in water.”

{Zizania palustris var. palustris} “Zizania aquatica ({Northern} Wild Rice). After the seeds had been stored in cold water for 5 to 7 months, good germination was obtained within 3 days. Seeds kept in water at 1-3C began to germinate…”


HYDROCHARITACEAE
“Vallisneria americana (Wild Celery) [Eel-grass] fruits were harvested and allowed to decompose in glass jars. The seeds which settled to the bottom to the jar were used for the storage tests. Of seeds stored in water at room temperature, 71 per cent germinated…, nearly all the remaining ungerminated seeds were immature or decayed. The seeds in cold storage in water gave good germination after 2, 5 or 7 months. Seeds exposed to bright light in the laboratory are slow to germinate, whereas those kept in diffuse light germinate more uniformly. Dried seeds gave almost no germination.”


JUNCACEAE
“Juncus articulatus ({Jointed} Rush).. Of the seeds stored in cold water for 5 or 7 months, 96 to 97 per cent germinated with 2 or 3 days. Of those stored in water at room temperature for 7 months, 61 per cent germinated, but when such seeds were chilled for 30 days, 86 per cent germinated. Dried seeds gave very poor germination”


LOBELIACEAE {? family}
“Lobelia Dortmanna. [Water Lobelia] Seeds stored in cod water for 2 to 7 months gave good germination. Dried seeds lose their viability…”


NAJADACEAE
“Potamogeton spp. …pondweed.. the results from the five species … indicate that seeds of Potamogeton germinate readily if first subjected to several months of cold storage in water without first allowing them to dry. Seeds stored in water without chilling germinated very slowly and irregularly. Seeds stored in water for 5 months at room temperature and then chilled of 39 days a 1-3C gave good germination within 10 days. Dry seeds showed almost no germination. The seeds with thin pericarps do not withstand drying but usually die. Those with a thick boy pericarp, upon drying, enter a long dormant period. Such seeds, when subsequently placed in water, germinate very irregular. Seeds of all five species were cut open after 5 months of dry storage. Only two gave any germination, P. pectinatus, 21 per cent and P. americanus {P. nodosus}, 19 per cent”

“Najas flexilis. [{Slender} Naiad] No germination was obtained from dried seeds or from seeds stored in water. Seeds chilled in water for one month germinated very slowly, a few at a time, for a period of 6 months. Seeds chilled for 7 months germinated uniformly and quickly, 87 per cent within 6 days”

“Najas marina," [{holly-leaf or marine} Naiad]… Water-stored chilled seeds germinated very poorly and irregularly. This may have been owing at least in part to immaturity of the sees used. Dried seeds did not germinate."


POLYGONACEAE
“Polygonum amphibium (Water Smartweed) seeds were slow to germinate. The only germination obtained was 26 per cent from seeds that had been in cold storage in water for 7 months. None of the seeds germinated until 45 days after they were placed in the germinator. … Seeds from each of the four storage treatments were cut open after 5 months in storage, and placed in germinators, but none germinated.”


PONTEDERICEAE {PONTEDERIACEAE]
“Heteranthera dubia ({water star-grass} Mud Plantain) gave good germination after 2 to 7 months in cold storage in water. Most of the seeds germinated within 10 days after were placed in the germinators. Unchilled water-stored seeds did not germinating, but when such seeds were chilled for 30 days after 7 months in storage, 86 per cent of them germinated within 10 days. Seeds stored dry failed to germinate even after subsequent chilling in cold water for 30 days.”

“Pontederia cordata (Pickerel-Weed) gave good germination after 5 to 7 months in cold storage in water. Water storage in the laboratory and dry storage of the seeds for 5 to 7 months did not kill the seeds but induced dormancy. When dried seeds were soaked and placed in cold storage for 30 days and then placed in germinators, 51 to 71 per cent of them germinated within 15 days.”


SCROPHULARIACEAE
“Veronica anagallis-aquatica.[{water speedwell} Brooklime] Seeds stored in water did not germinate until after 4 months of chilling. Seeds stored dry gave some germination after 2 months and good germination after 7 months in storage. Apparently these seeds withstand drying without going into a long dormant period.”


SPARGANIACEAE
“Sparganium spp. The seeds of Bur-reed are enclosed within a rather thick hard pericarp. Of the five species tested, only one germinated. Sparganium americanum gave 6 to 9 per cent germination after 5 to 7 months in cold storage in water. None of the seeds of any species stored dry or in water without chilling gave any germination. Sparganium eurycarpum seeds from which the pericarp had been removed decayed within a few days after placing them in the germinator. The results from Sparganium are inconclusive.”


TYPHACEAE
“Typha latifolia. The seeds of {common} Cattail are wind-disseminated and appear to withstand drying for a considerable time without losing their vitality. Of these dried seeds, after 5 to 8 months of storage without subjecting them to low temperature, 42 to 65 per cent germinated. Most of the seeds germinated within 10 to 12 days but some continued to germinate 30 days after the beginning to the test. No tests were made with water-stored seeds.”

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