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تبادل المعلومة عبر المواقع الإجتماعية
Culture in vitro du palmier dattier (suite)
Thesis
title: Improvement of the multiplication methods of date palm (Phoenix dactylifera L.) by culture of embryogenic
cell suspensions and application of arbuscular mycorrhizes in growth and protection of young plants
Abstract
The date palm (Phoenix dactylifera L.), a lon lived monocotyledon, is
facing various biotic and abiotic stresses. Urgent actions are needed
to improve the multiplication methods of this species. Date palm micropropagation
through culture of embryonic cell suspension and the application of
arbuscular mycorrhizes in growth and protection of seedling plants,
constitute promising tools for quick multiplication and protection
date palm plants.
The in vitro propagation of two date palm cultivars growing in Morocco,
Bou-Feggous (BFG) and Bouskri (BSK) was carried out using Murashige
and Skoog medium (MS) containing 5 mg/l of 2,4-dichlorophenoxyacetic
acid (2,4-D) and 5 mg/l of benzyl-6-aminopurine (BAP) to obtain callus.
This latter, was transferred on the same medium containing low concentrations
of 2,4-D (0.1 mg/l ) and BAP (0.5 mg/l) to obtain embryonic callus.
Using liquid media (cell suspension) to obtain somatic embryogenesis
needs the development of new culture media for the physiological maturation
and germination of somatic embryos. The study realized on embryogenic
cell suspensions revealed that the tissue and media browning is one
among other factors limiting somatic embryogenesis of date palm in
liquid media. This phenomenon was more or less controlled by the renewal
of culture medium each week interval during 45 days of suspension
culture. Addition of activated charcoal to liquid culture medium led
to decreased in tissue and medium browning and reduced phenolics and
peroxidase activity, in comparison with medium without charcoal. Addition
of gultamine (100 mg/l) to the culture medium of somatic embryos led
to decreased peroxidase activity and increased proteins content, when
compared with medium without glutamine.
The liquid medium with 0.3 mg/l BAP, allowed cell suspension cultures
to produce the greater globular embryos and the highest number of
somatic embryos in comparison with the other treatment for BFG and
BSK date palm cultivars.
Detailed morophological observations have revealed that the cells
destined to become somatic embryos divided into spherical proembryos
within 7-15 days, with subsequent development including the appearance
of globular, elongation and cotyledonary stage embryos. Somatic embryos
were conducted on MS liquid medium diluted a half, without plant growth
regulator and then transferred and cultured on MS solid medium supplemented
with NAA (0.1 mg/l). This protocol led to improve the embryo germination
ratio, which reached 22%.
The other method of multiplication and protection of date palm corresponded
to apply the arbuscular mycorrhizal fungi (AMF) on date palm seedlings.
After ten months of colonization, mycorrhizal plants showed a significant
increase in their growth expressed as shoot height, number of leaves
per plant, shoot weight, root weight and the total biomass. Mycorrhizal
and non-mycorrhizal (controls) date palm seedlings showed great differences
in their leaf contents of phosphorus (P), potassium (K+) and sodium
(Na+). When compared with controls, P increased more than two folds
in mycorrhizal plants, while the values of K+ and Na+ doubled.
When inoculated with Fusarium oxysporum f. sp. albedinis
(Foa, causal agent of Bayoud) by injecting roots with an Foa spore
suspension, mycorrhizal (M + Foa) and non-mycorrhizal (+ Foa) date
palm seedlings showed significant increases in their root total phenols
and peroxidase activities during the first month after inoculation.
The highest increases were found in mycorrhizal seedlings accompanied
by limited plant death. Mycorrhization alone did not affect significantly
total phenols and peroxidase activities during the first week of culture.
Plant death decrease in plant lots subjected to root inoculation with
the AMF fungus. As revealed by mycorrhization of date palm seedlings,
these results supported the hypothesis that induced resistance to
Bayoud disease is mediated by high increases in phenolic compounds
and peroxidase activities.
Liens utiles:
- Variétés (cultivars) de palmier dattier
- Pieds mâles et femelles
du palmier dattier. Peroxydases
- Culture des tissus chez le palmier dattier
- vitro-clones de palmier dattier au Maroc
- Palmier dattier au Maghreb
- Sauver les palmiers au Maroc
- Palmier dattier au Maghreb. principaux stress
- Embryogenèse somatique, mycorhization du palmier dattier
- Prémunition du palmier dattier contre le Bayoud -
Cerisiers à cerises sans pédoncules. Le pour et le contre
Le
cerisier (Prunus cerasus) appartient à la famille des
Rosacées. Le fruit est une drupe (fruit charnu) dont le noyau
lignifié est très solide. Il contient une ou deux graines
appelées amandes. Contrairement aux autres fruits comme les fraises,
les cerises ne poussent pas sur une longue période. La plupart
des cerises sont toutes prêtes en même temps.
Le
cerisier Prunus cerasus est une espèce allotétraploïde (AAFF) et comme l'évolution procède en général de types ayant moins de chromosomes vers des polyploïdes, l'hypothèse
fut faite que Prunus cerasus (AAFF) pourrait résulter d'une
hybridation naturelle entre le merisier P. avium, diploïde
(AA, 2n = 2x = 16) et le cerisier des steppes P. fruticosa
tétraploïde (FFFF, 2n = 4x = 32). Lors de cette fécondation,
P. avium aurait produit des gamètes non réduits
(AA) et P. fruticosa des gamètes normalement réduits
(FF).
Pour beaucoup de consommateurs de cerises, lefruit est indissociable
de son pédoncule (queue) qui est signe de la fraîcheur
de collecte. Cependant, la 'société de consommation'
peut nous présenter des cerises sans pédoncule pour
une consommation ambulatoire. Ainsi, le sélectionner doit puiser
dans la diversité génétique de tous les cerisiers
(loins ou proches génétiquement) les gènes
en faveur d'un détachement pédonculaire aisé
lors de la récolte et une aptitude à la subérisation
au niveau de la zone d'abscission. Cette aptitude au détachement,
mesurée par un dynamomètre numérique, permet
d'assurer un gain de temps dans la récolte et une préservation
meilleure du fruit. Les agriculteurs expérimentés peuvent
avoir une idée contraire. En effet, ils savent que lors de
la cueillette, il est très important d'enlever le pédoncule
avec la cerise afin de permettre à l'arbre de produire de façon
maximale l'année suivante. Si la queue reste dans l'arbre à
l'automne, il est probable que l'arbre donne moins de fruits lors
de la prochaine récolte, disent-ils. N'oublions pas, non plus,
les vertus des pédoncules (queues). Depuis des temps immémoriaux,
l'Homme a appris à faire sécher les queues pour en faire
des médicaments. Ce savoir ancestral a été confirmé
par la pharmacie moderne qui a constaté que les pédoncules
sont riches en flavonoïdes et sels de potassium. Notons que l'amélioration génétique du cerisier est
confrontée au phénomène de l'incompatibilité
pollinique. En effet, chez le cerisier, existe une incompatibilité
pollinique (inhibition de la croissance du tube pollinique). Les cerisiers
du même groupe d'incompatibilité ne peuvent se féconder
entre eux. Cette incompatibilité est liée à l'action
d'un locus S sui comprend deux parties, l'une exprimée dans
le style, et l'autre complémentaire exprimée dans le
pollen. Les groupes d'incompatibilité polliniques peuvent être
déterminés par PCR (développement d'amorces reconnaissant
des séquences des allèles
Sources :
- Filleron E. 2011. La cerise sans pédoncule : une innovation sur le marché de la cerise. Innovations Agronomiques 17 (2011),
227-240
Biotechnologies modernes. 'Protato', une pomme de terre (potato) génétiquement
modifiée riche en protéines : A Protein Rich GM Potato
The
recent issue of the Proceedings of the National Academy of Sciences (PNAS) reports the development of a genetically modified (GM) potato rich in protein by a team of scientists led by Dr. Subhra Chakraborty of the National Institute of Plant Genome Research (NIPGR) in close collaboration with the Central Potato Research Institute (CPRI) of India. The genetically modified potato is named 'Protato' which
contains 60% increase in total protein content developed by introducing
AmA1 gene (Amaranth Albumin 1) from edible amaranth plant into seven commercial varieties of potatoes.
The
GM potato plants were tested at three locations in India and the trial results demonstrated greater harvest and moderate increase in tuber
yield. Data on field performance and safety evaluation indicates that
the transgenic potatoes are suitable for commercial cultivation and have no negative effects on animal health. In addition, the concentrations
of several essential amino acids were increased significantly
in transgenic tubers which are otherwise limited in potato, resulted
in a significant increase in yield and enhanced nutrition. The article
also reported that the expression of AmA1 has potential for the nutritional
improvement of other food crops.
Full article: 'Next-generation protein-rich potato expressing
the seed protein gene AmA1 is a result of proteome rebalancing in
transgenic tuber' is available +html Supporting information on safety and efficacy of the protein
rich GM potato is available
For more information about biotech development in India contact b.choudhary@cgiar.org
and k.gaur@cgiar.org ........................ by Udupa
An
Alternative Approach to Genetically-Engineered Crops for Enhancing
Drought Tolerance
To
survive and flourish in rapidly changing environmental conditions, plants
use a complex family of hormones to regulate growth and reproduction.
One plant hormone, abscisic acid (ABA), coordinates responses
to stressors such as drought, extreme temperature and high salinity,
as well as regulating non-stress responses including seed maturation
and bud dormancy (for review, Aaron Santner & Mark Estelle, Nature
459, 1071-1078 (25 June 2009)).
In
a 2009 study published in Nature, showed precisely how the plant hormone
abscisic acid (ABA) works at the molecular level to help plants respond
to environmental stresses such as drought and cold. A family of proteins
recently identified as ABA receptors (Karsten Melcher et al.
Nature 462, 602-608 (3 December 2009),
), which modulate these stress tolerance response. These findings
could help engineer crops that thrive in harsh environments.
One
of ABA's effects is to cause plant stomata (pores) to close when plants
are stressed so that they can retain water. In the new study published
about 5 weeks ago (Karsten Melcher et al. Nature Structural &
Molecular Biology 17, 1102 (2010)
), researchers identified several synthetic compounds that fit well
with ABA's many receptors, or cellular "docking stations,"
to have the same effect. By finding compounds that can close these
stomata, researchers' findings could lead to sprays that use a plant's
natural defenses to help it survive harsh environmental conditions.
Spraying these compounds during drought situations would allow plants
to be more adaptable to drought. This approach could be more effective
than genetically engineered crops, said Karsten Melcher, one of the
authors of the paper.
Palmier dattier نخيل التمر
Date palm
Olivier الزيتون Olive
Pin d'Alep الصنوبر الحلبي
Aleppo pine
Atriplex القطف Atriplex
Céréales الحبوب
Cereals
Cactus الصبار Cactus
