Summary This study was conducted to examine the effect of biotin and thiamine concentrations on callus growth and somatic embryogenesis
of date palm (Phoenix dactylifera L.). Embryogenic callus derived from offshoot tip explants was cultured on hormone-free MS medium containing biotin at 0,
0.1, 1, or 2 mg l−1 combined with thiamine at 0.1, 0.5, 2, or 5 mg l−1. Embryogenic callus weight, number of resultant embryos, and embryo length were significantly influenced by thiamine and
biotin concentration. The optimum callus growth treatment consisted of 0.5 mg l−1 thiamine and 2 mg l−1 biotin. This treatment also gave the highest number of embryos. Embryo elongation was greatest at 0.5 or 2 mg l−1 thiamine combined with 1 mg l−1 biotin. Embryos from all treatments germinated and regenerants exhibited normal growth in soil. This study provides an insight
into the importance of optimizing various culture medium components to overcome in vitro recalcitrace of date palm. 相似文献
In Vitro Cellular & Developmental Biology - Plant - Plants that produce bioactive chemicals provide a viable in vitro method for producing key nutraceutical substances, especially in the... 相似文献
Summary A plant regeneration system applicable to 17 cowpea genotypes was developed. Cotyledons were initiated on 1/3 MS medium containing
15 to 35 mg N6-benzyladenine (BA) per 1 (66.6 to 155.3 μM) for 5 to 15 d. For shoot regeneration, the explants were transferred to a medium containing 1 mg BA per 1 (4.4 μM). Within 1 wk, shoot formation was visible at the proximal end of the cotyledons. Regeneration percentages (1% to 11%) and
the numbers of shoots (4 to 12 per explant) were significantly influenced by genotype. Culture duration and BA concentration
in the initiation stage significantly affected regeneration capacity. Explants initiated on media containing 15 mg BA per
1 for 5 d resulted in the highest percentage of explants capable of regeneration. Conversely, the highest number of shoots
was obtained from explants initiated on media supplemented with 35 mg BA per 1. Whole plants were obtained on a plant growth
regulator-free medium. To our knowledge, this is the first report of plant regeneration from U.S. commercial cowpea cultivars
and breeding lines. This system is adaptable to diverse cowpea genotypes and will facilitate cowpea genetic transformation.
Published with the approval of the Director of the Arkansas Agricultural Experiment Station. 相似文献
Summary A micropropagation system was developed forAcacia mearnsii De Wild., which is the principal source of the world’s tanbark and an excellent firewood. Shoot tips 5-mm long from 3-wk-old
seedlings germinated in vitro served as explants. The seeds were germinated on hormone-free MS medium and the shoot tips were
cultured on three-fourth-strength MS medium supplemented with combinations of auxins [indole-3-butyric acid (IBA) andα-naphthaleneacetic acid (NAA)] and cytokinins [kinetin and benzylaminopurine (BAP)]. Cultures were maintained at 25° ± 5°
C and exposed to 12-h photoperiods of cool-white fluorescent light (70 μEm−2·s−1). Multiple shoot formation was promoted by BAP at 2 mg · liter−1 (8.87μM) and higher combined with or without 0.01 mg · liter−1 (0.049μM) IBA. Cytokinins at concentrations of less than 1 mg · liter−1 combined with 0.01 to 0.1 mg · liter−1 auxin inhibited multiple shoot formation and promoted rooting of the shoot tip explants. Shoot multiplication cultures were
maintained by transferring segments of multiple-shoot clusters onto a medium containing 2 mg · liter−1 BAP and 0.01 mg · liter−1 IBA. Although higher levels of BAP promoted more multiple shoot formation, this BAP level allowed shoot elongation as well
as multiplication. In-vitro-produced shoots were induced to root on a range of NAA concentrations (0.0 to 0.8 mg · liter−1[4.3μM]) supplemented to half- or full-strength MS medium. The highest frequency of root proliferation was on half-strength MS medium
supplemented with 0.6 mg · liter−1 (3.22μM) NAA. Plantlets survived in potting soil and exhibited normal growth under greenhouse conditions. 相似文献
Summary Ethylene is a plant growth regulator that is known to influence in vitro morphogenesis. This study investigated the effects
of three ethylene inhibitors, silver nitrate (AgNO3), 2,5-norbornadiene, and cobalt chloride (CoCl2), on the regeneration of cowpea from cotyledon explants. Significant increases in the percentage of regeneration occurred
as a result of adding either 50 μM AgNO3 or 100 μM 2,5-norbornadiene. The number of shoots produced per explant was enhanced by adding 25 μM CoCl2 or 100 μM norbornadiene. Maximum shoot elongation was obtained with 25 μM of either CoCl2 or norbornadiene. The effect of the duration of exposure to AgNO3 was also determined. The greatest percent regeneration was obtained with the addition of 60 μM AgNO3 either to both the initiation and regeneration stages, or to only the regeneration stage. The promotive effects on organogenesis
in response to ethylene inhibitors suggests an important role for ethylene in the process of in vitro morphogenesis of cowpea
and may contribute to its normally low regeneration frequency. 相似文献
Summary Shoot multiplication was induced in cowpea, cv. Georgia-21, from shoot tip explants. Shoot tips, 5 mm long, were isolated
from in vitro-grown seedlings and cultured on MS medium containing N6-benzyladenine (BA) at 1, 2.5, or 5 mg/liter (4.4, 11.1, or 22.2 μM) or 6-furfurylaminopurine (kinetin) at 1, 2.5, or 5 mg/liter (4.6, 11.6, or 23.2 μM) combined with 2,4-dichlorophenoxyacetic acid (2,4-D) at 0.01, 0.1, or 0.5 mg/liter (0.05, 0.5, or 2.3 μM) or naphthaleneacetic acid (NAA) at 0.01, 0.1, or 0.5 mg/liter (0.05, 0.5, or 2.7 μM). Cultures were maintained at a 12-h photoperiod (40 μmol·m−2·s−1) and 23 ± 2° C. Treatments with BA induced greater shoot proliferation than those with kinetin. The highest number of shoots
was produced on 5 mg (22.2 μM) BA per liter in combination with NAA or 2,4-D at 0.01 mg/liter (0.05 μM). Callus proliferated from the basal ends of shoot pieces in all treatments. The cultures also formed roots in the presence
of kinetin, but not on BA-containing medium. To produce whole plants, the shoots were separated and rooted on 0.1 mg (0.5
μM) NAA per liter. Resulting plants grew normally under greenhouse conditions. Shoot tips provide an excellent explant source
for cowpea micropropagation and can be used for callus induction. 相似文献
Rice stem borer (Chilo agamemnon Bles.) is a primary insect pest of rice and is a major limiting factor to rice
production. Breeding for insect-resistant crop varieties has been an economic way of integrated pest management
(IPM) as it offers a viable and ecologically acceptable approach. This study was aimed to evaluate rice genotypes
for their resistance against rice stem borer. Seven parental genotypes with twenty one F1 crosses were evaluated
for genotypic variation in field experiments. Analysis of variance revealed significant differences for the studied
traits in almost all crosses and parents. In addition, the mean squares of parents versus their crosses were signifi-
cant for stem borer resistance and other associated traits. Moreover, both general combining ability (GCA) and
specific combining ability (SCA) variances were highly significant for all characters studied in the F1 generation.
Based on GCA, 4 genotypes (Sakha101, Gz6903-3-4-2-1, Gz9577-4-1-1 and Hassawi) exhibited highly significant
negative values for stem borer resistance (–0.53, –1.06, –0.18 and –0.49, respectively) indicating they are the best
combiners for stem borer resistance. Based on SCA analysis, nine cross combinations showed highly significant
negative effects for stem borer resistance. Similarly, the cross Giza178 Hassawi was the best combination with
significantly highest value for early maturity. In addition, seven crosses showed highly significant negative
SCA for plant height trait. On the other hand, for panicle length, number of primary branches/panicle, panicle
weight and 1000-grain weight, seven, four, eight and six crosses showed highly significant positive SCA, respectively. The result further revealed that the non-additive dominance genetic variance was higher than the additive
variance for all evaluated traits indicating that non-additive genetic variances have a role in their inheritance. The
broad-sense heritability estimates were high for all the studied traits. The stem borer resistance was significantly
correlated with panicle weight and 1000-grain weight, which also showed a highly significant correlation with
grain yield/plant. Thus these traits can be effectively employed in a breeding program to confer resistance against
stem borer infestation in rice. It was further supported by biplot analysis, which clustered these potentially important traits into two quadrants showing their importance in any future breeding program to control stem borer
infestation. This study has contributed valuable information for evaluation of genetic diversity in the local rice
germplasm and its utilization in futuristic rice genetic improvement programs. 相似文献
A common modern cultivation practice is bagging the fruit bunch if date palm (Phoenix dactylifera L.) which may influence fruit maturity and nutraceutical quality. Exposure of fruits to photooxidative stress induces changes in the endogenous concentrations of plant hormones and other metabolites, which may cause accelerated fruit maturity. This study was conducted to examine the effect of exposure to direct and indirect sunlight on date palm fruit development. The indirect sunlight treatment was simulated by fruit bunch bagging, a common practice in modern date production. The exposure of date palm fruits to direct sunlight-induced photooxidative stress causing an increased concentration of ascorbic acid and decreased content of chlorophyll, anthocyanins, carotenoids, and phenols compared to the fruit bagging treatment. Direct sunlight also reduced the concentration of phytohormones, including indoleacetic acid, gibberellin, and zeatin, but increased abscisic acid accumulation. The directly-exposed fruits reached a partially-mature stage (Rutab) in August, whereas the bagged fruits remained at the immature stage (Khalal). This study is the first to describe the biochemical basis of the observed improvement of date palm fruit development in response to reduced light intensity. Besides, it provides insights into controlling date palm fruit maturity and subsequently prolonging the shelf life dates on the tree; thus, extending the marketing period for the benefit of the farmers.
Appropriate knowledge of the parental cultivars is a pre-requisite for a successful breeding program. This study
characterized fruit yield, quality attributes, and molecular variations of ten tomato cultivars during three consecutive generations under greenhouse conditions. Peto 86, Castle Rock, and Red Star cultivars showed the highest
fruit yield (kg/plant), total phenolic compounds (TPC), and sap acidity. Principal component analysis categorized
the evaluated fruit yield into three groups based on their quality attributes. A robust positive correlation appeared
among traits inside each group. A positive correlation was likewise noticed between the first and the second
groups. However, a negative correlation was detected between the first, the second and the third group. Molecular
profiling, using seven inter-simple sequence repeat (ISSR) primers, produced 60 loci, including 49 polymorphic
loci. The molecular analysis also pinpointed the highest genetic similarity (0.92) between P73 and Moneymaker,
while the lowest genetic similarity (0.46) was observed between Castle Rock and Moneymaker. The cultivars
P73 and Moneymaker showed the lowest genetic distance (2.24), while the highest genetic distance (5.92) was
observed between Super Marmand and Peto86, on the one hand, and between Castle Rock and Moneymaker,
on the other hand. The chemical analysis of fruit sap indicated the highest levels of TPC, total flavonoids, anthocyanin, ascorbic acid and total soluble solids in Peto 86 and Castle Rock cultivars. Phylogeny analysis of tomato
cultivars based on morphological and molecular attributes indicated four distinct clades. Peto 86, Castle Rock, and Red star cultivars can be recommended for the tomato hybridization breeding programs in the future, with other
tomato cultivars as potentially high-yielding parents. 相似文献
Summary A system for the regeneration of spinach (Spinacia oleracea L.) from mature dry seed explants has been established. The response of two commercial spinach cultivars, ‘Grandstand’ and
‘Baker’, was examined. Callus proliferation was most prominent on MS medium supplemented with 9.3 μM of 6-furfurylaminopurine (kinetin) and 3.39 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Adventitious shoot formation was observed within 8 wk after callus was transferred
onto regeneration medium. Shoot regeneration was best from callus induced on 9.3 μM kinetin and 4.56 μM 2,4-D. The regeneration medium contained 9.3 μM kinetin, 0.045 μM 2,4-D, and 2.89 μM gibberellic acid (GA3). Shoots were rooted on hormone-free medium, and plants grown in a greenhouse showed normal phenotype. This system is beneficial
in rapid propagation of spinach plants, particularly when only a limited number of seeds are available. 相似文献