Age Of Mother Plants Research Articles

Standardization of grafting technique in Kusum [Schleichera oleosa (Lour.) Oken

The species, Schleichera oleosa (Kusum), holds an important place in the livelihood of tribal farmers in eastern region of India. It is getting popular due to its ethnobotanical values and its potential use as host plant for lac production. Its natural population and genetic variability is declining at faster rate due to deforestation and human interventions. Mass production of Kusum seedlings is a major challenge and moreover, auto-generation of heterozygous nature in plants calls for long term experiments for its genetic improvement which require huge monetary investments. Moreover, the factors like low quality and quantity planting materials and the problem of restricted growth in plants raised from seeds hinder the interest of the farmers. Hence, clonal propagation through grafting could be an option. The scientific knowledge on application and standardization of various approaches like girdling of scionstick branches, age of mother plant, rootstocks, etc. of Kusum are extremely limited. Keeping these in view, an experiment was conducted during 2018–2021 to standardize grafting technique in Kusum. The result revealed that grafting methods affected the graft’s success significantly. Cleft grafting was found to be the most successful (72.38% graft) than veneer grafting (64.46%). Moreover, the scions collected from tree aged <15 years showed maximum success in grafting (upto 86.23%). This study revealed the importance of girdling of scionstick branches, girdling age (3 months), girdling-ring thickness (6–8 mm), and selection of two years old rootstock to maximize graft success upto 86.25% in Kusum. Furthermore, season also play an important role in successful grafting. The period from April to June was the best time for grafting with 73.31% success.

Late-Autumn Ramet Sprouting of Three Arable Creeping Perennial Weed Species

Elymus repens (L.) Gould), Cirsium arvense (L.) Scop. and Sonchus arvensis L. are important arable creeping perennial weeds in Europe. These are clonal plants with subterranean reproductive organs (E. repens, rhizomes, the two dicots, horizontal creeping roots) sprouting from ramets. We tested the sprouting ability and early growth of ramet sprouts at temperatures typical for Nordic autumn climate and with different preconditions of the mother plant (time in autumn, mother plant age, climate change experiences of the mother plants (two experiments)). The species reacted differently, with S. arvensis not sprouting at all, and C. arvense ramets sprouting at higher temperatures than those of E. repens, which sprouted at all tested temperatures. Plant age affected only the ramet sprout biomass of E. repens. Climate change during mother plant growth only affected C. arvense, with the highest above-ground biomass of the sprouted ramets at an elevated temperature and ambient CO2. Testing earlier in autumn showed more sprouting and biomass for C. arvense and E. repens than testing later in the season. The observed temperature responses confirmed more and bigger sprouts with higher autumn temperatures. Controlling the sprouted ramets in autumn is easier for E. repens than for C. arvensis. Due to their low/no sprouting ability in autumn, the ramets of S. arvensis cannot be controlled in autumn.

Fire Severity Drives the Natural Regeneration of Cytisus scoparius L. (Link) and Salix atrocinerea Brot. Communities and the Germinative Behaviour of These Species

Research Highlights: Data indicated that fire severity modulates natural regeneration of Cytisus scoparius and Salix atrocinerea communities and drives much stronger effects on the germination of the dominant species. Background and Objectives: Previous studies demonstrated that fire severity induces different behaviours in plant species. Mother plant age is an important feature that must also be considered in plans of forest restoration. The objectives were to determine, in field studies, the effect of fire severity on the natural regeneration of C. scoparius and S. atrocinerea communities, to know the role of mother plant age on the germination of seeds of C. scoparius and S. atrocinerea, and to quantify their germination response at different levels of fire severity, in laboratory settings. Material and Methods: We have analysed the role of fire severity on the natural regeneration of C. scoparius and S. atrocinerea communities considering cover and height. Forty 30 × 30 m plots were randomly located in C. scoparius and S. atrocinerea communities. Fire severity on the germination of dominant species was tested through different levels of smoke, charcoal, ash, and heat. Results: High severity reduced the vertical cover and growth in height of the two communities and favoured the increase of cover of woody species in the C. scoparius community and herbaceous species in the S. atrocinerea community. Mother plant age determined germination percentages of C. scoparius seeds. Germination of C. scoparius was increased by moderate heat, and heat and smoke; and fire severity greatly reduced germination of S. atrocinerea. Conclusions: The regeneration responses after fire were largely controlled by interactions between the fire severity and the individual species regeneration strategies. For restoration purposes, C. scoparius seeds should be treated with 80 °C and smoke for 10 min, in order to increase germination; however, Salix seeds should be used without treatment and immediately after dispersion.

A leaf bud technique for rapid propagation of cassava (Manihot esculenta Crantz)

The slow rate of multiplication is one of the main constraints on the production of cassava (Manihot esculenta Crantz). This work aimed to evaluate the use of leaf buds for rapid propagation of cassava varieties. Leaf buds were excised from three cassava varieties (BRS Kiriris, 98150-06 and 9624-09) for plantlet generation. The experiment was completely randomized with a 5 (age of mother plant) × 3 (position of the leaf buds on the stems) × 2 (agrochemical treatments) factorial design. Data were collected on leaf sprouting percentage (Spro.Per), plantlet height (Plant.Hei) and total dry mass of plantlets (Dry.Mass.Plant). There was a difference between the three traits for most of the varieties, demonstrating significant effects on the agronomic attributes evaluated. Better agronomic performance (higher sprouting percentage, plantlet height and total dry mass) in plantlets was observed in leaf buds of: i) maturing plants up to six months old; ii) more herbaceous (upper) parts; and iii) plants treated with agrochemicals (fungicides and insecticides). Considering four-month-old plants, three annual cycles, and an 81 % average sprouting, it would be possible to reach an annual multiplication rate of 1:72, which is much higher than that achieved by traditional methods using mature stem cuttings from 12-month-old plants (around 1:5). These results are important because they demonstrate the possibility of using cassava leaf buds to produce high-quality plantlets rapidly for greater multiplication and diffusion of new varieties and cultivation on a larger scale.

Role of serotiny on Pinus pinaster Aiton germination and its relation to mother plant age and fire severity

Abstract: Serotiny degree may hypothetically depend on mother plant age and fire severity, and fire severity can strongly affect the regeneration of Pinus pinaster Aiton, which is an obligate seeder species with aerial seed banks stocked in cones showing a certain degree of serotiny. The main objective of this study was to evaluate the effect of serotiny and mother plant age on seed germination of P. pinaster in relation to fire severity. For this purpose, cones were collected in two stands from mother trees of different ages. Serotinous cones were opened in oven at increasing temperatures to determine the number of seeds released. The length of cones and the number and weight of seeds were measured. Seeds from both classes of mother plant age were subjected to 34 different treatments simulating different fire severity levels, and their germination was recorded. The results showed that serotiny was significantly higher in cones from young mother trees. Seed germination in the control groups from serotinous cones was always higher than that from non-serotinous cones without thermal shock. Fire severity decreased seed germination as fire severity increases in both mother age classes. Mother plant age was related to the serotiny level, which was higher in young than in old trees, suggesting a strong selection in the population due to a recent fire.

Repeated Stand-Replacing Crown Fires Affect Seed Morphology and Germination in Aleppo pine.

Post-fire reproductive niche of Aleppo pine (Pinus halepensis) is deeply interlaced with fire products. Indeed, the high pH and low osmotic potentials of ash beds under burnt crowns constitute the main constraints to seed germination. In this study, we aim to investigate whether fire recurrence, through the physico-chemical constraints imposed by the ash beds, affects the reproduction ability of P. halepensis at the germination stage. To this aim, Aleppo pine seeds were collected in neighboring even-aged stands subjected to 0, 1, or 2 fires (namely fire cohorts), and seed morphology and germination performance, in terms of cumulative germination and germination kinetics, were studied under increasing osmotic potentials (from 0.0 to −1.2 MPa) and pH (from 6 to 11). Besides fire history, the role of ontogenetic age of mother plants on seed morphology and germination was also investigated. Differences in seed morphology among the three cohorts have been highlighted in a multivariate context, with anisotropic enlargement of the seeds produced by pine stands experiencing repeated fires. The patterns of seed germination varied primarily in relation to the fire cohort, with seeds from the pine stand experiencing repeated fires exhibiting enhanced tolerance to pH stress. Conversely, germination performances under osmotic constraints mainly depends on tree ontogenetic stage, with an involvement of fire history especially in the timing of seed germination. Our results suggest that, at least in the short term, fire recurrence does not constrain the reproduction ability of Aleppo pine. These results highlight the need for further research to elucidate the mechanisms behind these responses to recurrent fires.

Ontogenetic and trans-generational variation of essential oil composition in Agastache rugosa

Agastache rugosa is an important medicinal and aromatic crop cultivated in East Asia and an ornamental in other temperate regions. The factors influencing the diversity of volatile profiles in this and many other aromatic plants remain largely undiscovered. In this study, a relationship between the age of mother plants and the volatiles profile of the progeny was investigated using Gas Chromatography–Mass Spectrometry, both in plants cultivated conventionally for three years and in vitro shoot cultures.The essential oil contains a major phenylpropanoid methyl chavicol (estragole) as well as minor mono- and sesquiterpenoids but the composition is very variable. The variability of composition in the progeny was indeed different in plants obtained from seeds coming from one-, two- and three-year old parents but also between young (one-year-old) and older (two- and three-year-old) plants. The quantitative variation among individuals was mainly in the content of methyl chavicol (from ca. 1% up to over 90%), menthone/isomenthone pair in leaves (from traces to 59%), and additionally pulegone (traces to 51%) in inflorescences. Limonene was least variable averaging between 8% and 25%. The variability tended to decrease and the proportion of methyl chavicol increased along with the age of parent plants. Two- and three-year-old plants were also producing higher yields of essential oil with average of 2.1% and 2.6%, respectively, compared with 1.2–1.9% in one-year old plants.In conclusion, the comparative analysis of essential oil and headspace revealed that volatile organic compounds profile of A. rugosa was dependent on the age of parent plants.

Can the mother plant age of Acacia melanoxylon (Leguminosae) modulate the germinative response to fire?

Acacia melanoxylon R.Br. (Leguminosae) is one of the most widely distributed tree species in the world. It has significant commercial use but can be a danger to natural ecosystems as an invader species. For these reasons it is necessary to have a deep knowledge about its germinative response to fire and the role the mother plant age plays in that response. In this work we assessed the effects of the interaction of the mother plant age with the main fire agents (smoke, charcoal, ash and heat) on the germinative response of A. melanoxylon. To reach this aim, germination tests were conducted with seeds from young, intermediate and mature mother plants, with 20 treatments each applied. Results show that fire can act as a great stimulator of the germination of A. melanoxylon but it can also strongly inhibit it. The mother plant age does not modify the final germination values, but it influences the time in which the first germinations occur after fire. This trait can be more important than the final germination percentage when looking at the success of post-fire regeneration. These results have important implications for A. melanoxylon management, for both species control and ecological restoration purposes.

Effects of maternal environmental factors on physical dormancy of Astragalus nitidiflorus seeds (Fabaceae), a critically endangered species of SE Spain

The viability and seed dormancy of the critically endangered species Astragalus nitidiflorus were tested during eight consecutive years (2006–2013) in order to determine if the high physical seed dormancy described in a previous study is affected by annual or seasonal environmental conditions. Also, the effects of maternal factors – such as fruit position in the inflorescence or seed position in the fruit, the age of the mother plants, and water stress – on seed viability and dormancy were tested. In order to determine the variation in the degree of germinability between years, ripe seeds were harvested each July from 2006 to 2013 and their viability and dormancy were tested. Moreover, in 2013 new seeds were collected to check the effects of the maternal factors mentioned above. A trial with potted plant in greenhouse was performed to corroborate the observed field data about the effect of water stress suffered by the mother plant on seed dormancy. The results show a high variability over the years in the physical dormancy of A. nitidiflorus seeds because maternal environmental factors such as drought or mother plant age influence the proportion of seeds that enter dormancy. This in turn determines the proportion of seed that becomes part of the seed bank each year and also the age structure of the natural population. The conservation programs for this critically endangered species should consider these results to implement measures to prevent the extinction of the species.

Some propagation methods for cloning holm oak (Quercus ilex L.) plants

Abstract Holm oak (Quercus ilex L.), a typical evergreen tree of the Mediterranean area, is very important due to its ecological and economical values. Propagation of this species is extremely difficult and traditionally carried out only by seed germination. In this work, mature acorns were germinated in vitro and in peat substrate in aseptic and non-aseptic conditions. Explants from the seedlings obtained were propagated in vitro in WPM plus 4 µM BA. Plant regeneration was achieved from hypocotyls and root segments cultured in vitro on modified Gamborg medium plus 20 µM BA and 20 µM NAA. 13.8% of the hypocotyls and approximately 30% of the root segments developed both shoots and roots after 30 days of culture. Rooting of stem segments was obtained both in vitro and ex vitro by basal dipping in IBA solutions. Within ex vitro rooting, mother plant age had major influence on the percentage of rooting of the cuttings as the younger plants showed higher ability to root. In this way, Q. ilex plants could be propagated and cloned. The procedure described here would be a very useful tool for breeding programs since vegetative propagation of selected individuals can be achieved.

Effect of mother plant age on germination and size of seeds and seedlings in the perennial sedge Carex secalina (Cyperaceae)

The performance of seeds and seedlings in relation to the age of the mother plant was studied in Carex secalina. Seeds of this sedge can differ substantially in size. We planted 100 C. secalina individuals from three populations in a common garden and followed them for four years. We found that mean seed mass varied with plant age, but the pattern of variation was population-specific, with only one population showing significant reduction in seed mass with age. Similarly, germination frequency changed with age differently in different populations. The relationship between the age of the mother plant and the height of emerged seedlings did not differ between populations. In spite of the fact that plant size and mean seed mass exhibited similar patterns of variation within populations, there was no correlation between these two variables at the level of individuals. This means that the size of C. secalina tufts does not determine how big the seeds will be. Moreover, there was no relationship between mean seed mass and the height of seedlings. Presumably, factors intrinsic to each plant determine the production of either small or large seeds in a population-specific way.

Seed germination in sedges: a short review

Seed germination in sedges: a short review Five patterns of seed germination in the sedges of the genus Carex are presented, based on the literature data and the results of the authors' own research. They include the pattern of C. acutiformis, C. arenaria, C. remota, C. flava and C. communis. These patterns were constructed on the basis of seed specific requirements for development, such as stratification, temperature, dormancy and time of germination. Majority of sedges follow the pattern of C. acutiformis or C. remota. In both cases, stratification and either high or low temperature are essential for seed germination. Seeds that start to germinate early (C. remota pattern) are characterized by the absence of the distinct peaks of germination, as opposed to the C. acutiformis pattern with the germination peak in March. Our long-term investigations, conducted on the group of individuals in controlled conditions, revealed significant differences in seed size and the ability of seeds to germinate depending on the age of mother plants. We postulate that mother plant age is a new factor that should be considered in the construction of seed germination patterns.

Mother plant age and seasonal influence on in vitro propagation of Quercus euboica Pap., an endemic, rare and endangered oak species of Greece

A micropropagation method for Quercus euboica Pap. was developed. Nodal explants from seedlings gave higher multiplication rates than explants from adult plants. Cultures initiated at the beginning of May produced the highest percentage of shoot forming explants and multiplication rate. Woody Plant Medium (WPM) salts, with 100 mg l−1 myoinositol, 1 mg l−1 thiamine, 0.5 mg l−1 pyridoxine, 0.5 mg l−1 nicotinic acid and 3% sucrose was used as basal medium and several cytokinins at various concentrations were evaluated for their effect on shoot multiplication. The highest shoot multiplication rate was obtained with 4.44 μΜ BA. IBA at 9.84 μΜ in the culture medium during the first week of culture, and if followed by culture in hormone-free medium, gave the best rooting results. Darkness at the beginning of the rooting period did not improve rooting. The use of plastic wrap as a cover material of the culture vessels enhanced rooting percentage and root number. Plantlets acclimatized ex vitro in soil from the natural environment of the species survived at a higher percentage (up to 93%) and had more vigorous growth than plantlets grown in a compost–perlite (2:1 v/v) medium (up to 36%).

Reproductive capacity of Pinus nigra ssp. salzmannii in relation to mother plant age

This paper analyses the possible reduction of fertility in Pinus nigra ssp. salzmanii as trees age in the managed forests of Cazorla mountain range (Southern Spain). Fertility was assessed by the combined values: frequency of empty seeds and viability of full seeds. Performance of one year seedlings was also evaluated. Plant material came from reproductive trees of up to 120 years old (the rotation period in the study area), and from older trees of over 1000 years old. The older tended to produce larger quantities of empty seeds than the younger ones, and their filled seeds tended to be lighter and slower to germinate. Nevertheless, the difference in these parameters shown by the trees studied was not so great so as to establish that ageing Salzmann pines are unable to regenerate managed forests. The growth of first year seedlings was positively correlated to seed weight and, therefore, negatively correlated to mother plant age. However, these factors could only account for a small amount of the variability in the size of first-year seedlings. Results suggest that reproductive function works normally in the very old (senescing) Salzmann pines, this being important in relation to the maintenance of biodiversity in the managed mountain forests of Southern Europe.

In vitro multiplication of cashew ( Anacardium occidentale L.) using shoot node explants of glasshouse-raised plants

Using glasshouse-raised plants (1 month, 1 year and 5 years old), factors affecting shoot development from shoot nodes of two Brazilian and one Tanzanian elite selections of cashew (Anacardium occidentale L.) were assessed. Sprouting of buds decreased strongly with increasing age of mother plants. Solidified media, mainly when purified agar was used, gave better results than liquid medium. Murashige and Skoog salts containing 1/2-strength macroelements were the most suitable for bud sprouting and shoot elongation. Vitamins and sucrose concentration did not have a significant effect but by replacing 20 g/l sucrose with glucose or maltose all estimated parameters were improved. Gibberellins supported bud sprouting and shoot elongation but blocked rooting. Shoots developed in the presence of cytokinins were short and produced axillary branches. Activated charcoal, cultivation of explants in darkness for the first 7 days and superoptimal temperature (35 °C) decreased bud sprouting and supported shoot elongation. Microshoots rooted in vitro at a frequency of 42% when cultured for 5 days with 100 μμ indole-3-butyric acid. Over 40% of rooted microshoots survived weaning.

The growth and form of potted mother plants of Eucalyptus globulus Labill. ssp. globulus in relation to the rooting ability of stem cuttings

SummaryClonal mother plants of Eucalyptus globulus were grown in 10 l pots in a Portuguese nursery and lightly harvested for stem cuttings every 2±4 weeks. Shoot length, within a crown size and across crown sizes, was poorly related to the rooting ability of derivative cuttings. The chronological age of mother plants, at least up to two years, also had little effect on the propagation traits of cuttings, and variation between individual mother plants was generally non-significant. Rooting of cuttings was strongly related to pre-harvest shoot extension rates (cm per shoot per week), the cuttings productivity of mother plants in the previous interval (cuttings per plant per week), and to the reciprocal of a shoot dominance index at harvest (principal shoot length/number of cuttings harvested). These variables were easy to measure and accounted for nearly all of the variation in rooting ability between harvests of cuttings within the clone.

Influences of Environmental and Physiological Conditions on Floral Bud Formation of Torenia Stem Segments Cultured in vitro

Internodal segments of Torenia fournieri Lind. differentiated floral buds when they were grown on a defined nutrient medium lacking NH 4 NO 3 . Two environmental factors, temperature and light, strongly affected floral bud formation. A temperature of 25 ± 2 °C, 8 hr short day photoperiod, and a light intensity of 5000 lux gave the best flowering response. Physiological factors such as the size of explants, the age of mother plants and the stem portions from which explants were taken, also influenced floral bud formation. The highest percentage of floral bud formation was obtained with 4 mm long explants prepared from the 2nd stem internodes of 12 week old plants, of which 91% of cultures produced floral buds.