zunia.vn

Tuyển sinh 2024 dành cho Gen-Z

zunia.vn

» Luận Văn - Báo Cáo

» Báo cáo khoa học

Báo cáo lâm nghiệp: "Storage of non-dormant hardwood seeds"

Chia sẻ: Nguyễn Minh Thắng | Ngày: | Loại File: PDF | Số trang:3

Báo xấu

27
lượt xem 1
download

Download Vui lòng tải xuống để xem tài liệu đầy đủ

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Storage of non-dormant hardwood seeds...

Chủ đề:

Bình luận(0) Đăng nhập để gửi bình luận!

Lưu

Nội dung Text: Báo cáo lâm nghiệp: "Storage of non-dormant hardwood seeds"

Storage of non-dormant hardwood seeds: trends new M. Bonnet-Masimbert 2 C. Muller 1 1 Laboratoire de Graines, For6t d’Amance Champenoux, BP 35, 54280 Seichamps, INRA-CRF and 1NRA, 2 Station dAmelioration des Arbres Forestiers, Ardon 45160 Olivet, France dium at 3-4°C), is limited in dealing with the Introduction heterogeneity within a seed lot. A new and original methodology has been More than 60% of forestry seeds, espe- developed on the basis of Polish research work to beechnuts (Suszka, 1975). It elimi- applied cially hardwood species, are in a more or nates the dormancy before storage, allowing a less deep dormancy state. As a con- continuous supply of non-dormant seeds ready sequence of its important genetic variabili- to germinate. Dormancy is eliminated by pre- ty, this dormancy is very heterogeneous: it treatment without medium. Seeds are hydrated, maintained at a controlled level of moisture can vary from year to year, from seed lot content (permitting the removal of dormancy to seed lot and between seeds within a without allowing germination) and finally de- seed lot. Generally, it is a type of physio- hydrated to below 10% moisture content (% logical dormancy caused by a germi- MC) before storage. This method allows a fast nation-inhibiting mechanism in the embryo and uniform germination in the laboratory as well as in the nursery. which often requires a long prechilling pe- We have developed this methodology further riod (1-8 months) to eliminate it. Some- in our laboratory and report here the results times, this physiological dormancy can be Fagus obtained with: silvatica, Fraxinus excel- associated with a physical impermeability sior and Prunus ;3vium. of the seed coat to water or with a morphological underdevelopment of the embryo. Nurserymen are generally una- Results ware of the dormancy requirements of their seeds, which has resulted in an Fagus silvatica enormous waste of seeds and mediocre yields in the nurseries. Beechnuts are typical examples of seeds with a variable but often very deep dor- mancy. Long-term storage of the seeds is Materials and Methods now possible. However, due to dormancy problems, nurserymen still have some dif- ficulty producing the desired number of The classical method of breaking the dormancy, seedlings even from high quality seed lots. stratification (i.e., pretreatment on a wet me-
cal stratification procedure. Pretreatment There are 3 possible methods of break- before storage produced significantly bet- ing the dormancy of beechnuts: before, ter results. We are now storing more than after or during storage. A dormancy- 30 non-dormant seed lots, some of them breaking treatment applied before storage is the only one providing a constant supply for nearly 6 yr. of dried, non-dormant beechnuts that are Of special interest are the results for able to germinate without any pretreat- nursery bed emergence, probably indi- ment (Muller and Bonnet-Masimbert, cating a good adaptation of the treated 1985). seeds to irregular environmental condi- tions in a nursery (Muller and Bonnet- optimum conditions of the treatment The Masimbert, 1989). hydration of the seeds to 30% mois- are: ture content (fresh weight basis) and maintaining the seeds at 3°C for a period Fraxinus excelsior 2 wk longer than the classical cold stratifi- cation method. This precise 30% MC of the seed is enough for the dormancy Samaras of Fraxinus excelsior present a breaking process to function. However, it physiological dormancy combined with an does not allow the seeds to germinate underdeveloped embryo. For breaking the and, after pretreatment, seeds be dormancy of this species, it was necessa- can dried and stored for several years. ry to apply a warm + cold phase treatment for 32 wk. Non-dormant beechnuts have been test- ed in the laboratory and in the nursery. As for beechnuts, we have different TableI shows the results for pretreatment ways to combine the dormancy breaking of seeds without medium, either before or treatment after collection and storage after storage, in comparison to the classi- (Table 11). The dormancy can be removed
before (i.e., after collection), after or after storage periods of up to 5 yr without during storage. It is now possible to elim- any pretreatment represents real progress inate prestorage dormancy after col- in the technology of forestry seed hand- lection, either by affecting underdevelop- ling. Especially well-adapted to the normal ment (i.e., warm phase) or under- heterogeneity of forest seeds, this new methodology has been tested on a large development + dormancy (i.e., warm + cold phase). scale with Fagus silvatica in the seed plant of the French Office National des For6ts with high hopes of yielding sub- Prunus avium stantial improvement in production of beech seedlin It is presently the best s. d For this species, an important dormancy method for the nurseryman who can now problem also exists, which results in poor choose the date of sowing in relationship control of germination, a huge waste of to good climatic; conditions, whereas form- seeds and poor yields in the nursery, rare- erly the date was determined by the ly exceeding 15-20%. The deep dorman- beginning of the pretreatment (hence 1-8 cy which affects the seeds can be earlier). mo removed with an alternate warm and cold Moreover, with reduced failure at the treatment applied with or without medium. time of germination, a decrease in waste For the last few years, we have tried to of forestry seeds and probably in waste of determine the optimal treatment conve- important genotypes may be a reasonable nient for all seed lots. Presently, the best expectation. one is 3 warm and 3 cold phase treat- ments. Although this protocol yields a complete and uniform germination, it is very long and often needs 20-24 wk befo- References re the beginning of the germination. For interested in this we were reason, applying the new methodology before Muller C. & Bonnet-Masimbert M. (1985) Levee storage. Good results have been obtained de dormance des faines avant leur conserva- after 1 yr of storage with non-dormant tion: r6sultats preiiminaires. Ann. Sci. For. 42, stones. 385-396 Muller C. & Bonnet-Masimbert M. (1989) Break- ing dormancy before storage: an improvement to processing of beechnuts (Fagus silvatica). Conclusion Seed Sci. Techno,’. (in press) Suszka B. (1975) Cold storage of after-ripened Today, the ability supply, at any time, to beech (Fagus silvatica) seeds. Arbor. Kornickie non-dormant seeds, ready to germinate, 299-315 5

CÓ THỂ BẠN MUỐN DOWNLOAD

LV.26: Bộ 320 Luận Văn Thạc Sĩ Y Học

320 tài liệu

1257 lượt tải

THÔNG TIN

TRỢ GIÚP

HỖ TRỢ KHÁCH HÀNG

Theo dõi chúng tôi

Chịu trách nhiệm nội dung:

Nguyễn Công Hà - Giám đốc Công ty TNHH TÀI LIỆU TRỰC TUYẾN VI NA

LIÊN HỆ

Địa chỉ: P402, 54A Nơ Trang Long, Phường 14, Q.Bình Thạnh, TP.HCM

Hotline: 093 303 0098

Email: support@tailieu.vn

Giấy phép Mạng Xã Hội số: 670/GP-BTTTT cấp ngày 30/11/2015 Copyright © 2022-2032 TaiLieu.VN. All rights reserved.