In vitro germination of Abricó-de-Macaco (Couroupita guianensis aubl.)zygotic embryos in different culture media and light spectra

ABSTRACT: Couroupita guianensis Aubl. is an Amazonian forest species with important medicinal and ornamental value. This study evaluated the effect of different culture media and light spectra on the in vitro germination and development of the zygotic embryos of C. guianensis. The culture media, MS and WPM, were evaluated without the addition of plant growth regulators and were associated with four LED light spectra: white (CW), 70% red + 30% blue (R2B), 100% red (R), and 100% blue (B). One hundred percent of the seeds successfully underwent in vitro germination, and the culture media did not interfere with embryo development. In addition to this, the different light spectra induced in vitro morphogenesis and R2B treatment significantly promoted the production of secondary roots. This effect may aid in the rooting and acclimatization of seedlings of this species.

Halotolerant Microbial Consortia for Sustainable Mitigation of Salinity Stress, Growth Promotion, and Mineral Uptake in Tomato Plants and Soil Nutrient Enrichment

Salinity significantly impacts the growth, development, and reproductive biology of various crops such as vegetables. The cultivable area is reduced due to the accumulation of salts and chemicals currently in use and is not amenable to a large extent to avoid such abiotic stress factors. The addition of microbes enriches the soil without any adverse effects. The effects of microbial consortia comprising Bacillus sp., Delftia sp., Enterobacter sp., Achromobacter sp., was evaluated on the growth and mineral uptake in tomatoes (Solanum Lycopersicum L.) under salt stress and normal soil conditions. Salinity treatments comprising Ec 0, 2, 5, and 8 dS/m were established by mixing soil with seawater until the desired Ec was achieved. The seedlings were transplanted in the pots of the respective pH and were inoculated with microbial consortia. After sufficient growth, these seedlings were transplanted in soil seedling trays. The measurement of soil minerals such as Na, K, Ca, Mg, Cu, Mn, and pH and the Ec were evaluated and compared with the control 0 days, 15 days, and 35 days after inoculation. The results were found to be non-significant for the soil parameters. In the uninoculated seedlings’ (control) seedling trays, salt treatment significantly affected leaf, shoot, root dry weight, shoot height, number of secondary roots, chlorophyll, and mineral contents. While bacterized seedlings sown under saline soil significantly increased leaf (105.17%), shoot (105.62%), root (109.06%) dry weight, leaf number (75.68%), shoot length (92.95%), root length (146.14%), secondary roots (91.23%), and chlorophyll content (−61.49%) as compared to the control (without consortia). The Na and K intake were higher even in the presence of the microbes, but the beneficial effect of the microbe helps plants sustain in the saline environment. The inoculation of microbial consortia produced more secondary roots, which accumulate more minerals and transport substances to the different parts of the plant; thus, it produced higher biomass and growth. Results of the present study revealed that the treatment with microbial consortia could alleviate the deleterious effects of salinity stress and improve the growth of tomato plants under salinity stress. Microbial consortia appear to be the best alternative and cost-effective and sustainable approach for managing soil salinity and improving plant growth under salt stress conditions.

Effect of growth regulators (IBA and NAA) on rooting and survival of guava air layers

The present investigation was conducted at Fruit Nursery, Department of Horticulture, College of Agriculture, Gwalior during the year 2015-16 on guava cv. Gwalior-27. The treatment combinations comprised with four concentration of IBA viz., 0ppm (I0), 7500ppm (I1), 10000ppm (I2) and 15000ppm (I3) and four concentration of NAA viz., 0ppm (B0), 50ppm (N1), 100ppm (N2) and 150ppm (N3). Results revealed that higher concentration of IBA (15000 ppm) and NAA (150 ppm) gave significantly highest results on callusing, number of primary and secondary roots, root weight per air layer, rooting and survival percentage over other lower concentrations while, combined application of higher concentration of both the growth regulators (I3N3) also gave higher results for all the parameters however, it was statistically at par with application of IBA @ 15000 ppm + NAA @ 100 ppm (I3N2) for all the parameters except survival percentage.

Rooting in the Desert: A Developmental Overview on Desert Plants

Plants, as sessile organisms, have evolved a remarkable developmental plasticity to cope with their changing environment. When growing in hostile desert conditions, plants have to grow and thrive in heat and drought. This review discusses how desert plants have adapted their root system architecture (RSA) to cope with scarce water availability and poor nutrient availability in the desert soil. First, we describe how some species can survive by developing deep tap roots to access the groundwater while others produce shallow roots to exploit the short rain seasons and unpredictable rainfalls. Then, we discuss how desert plants have evolved unique developmental programs like having determinate meristems in the case of cacti while forming a branched and compact root system that allows efficient water uptake during wet periods. The remote germination mechanism in date palms is another example of developmental adaptation to survive in the dry and hot desert surface. Date palms have also designed non-gravitropic secondary roots, termed pneumatophores, to maximize water and nutrient uptake. Next, we highlight the distinct anatomical features developed by desert species in response to drought like narrow vessels, high tissue suberization, and air spaces within the root cortex tissue. Finally, we discuss the beneficial impact of the microbiome in promoting root growth in desert conditions and how these characteristics can be exploited to engineer resilient crops with a greater ability to deal with salinity induced by irrigation and with the increasing drought caused by global warming.

Impact of Auxins on Rooting and Establishment of Seedless Lemon (Citrus limonL. Burm.) Air-layers for Successful Propagation

Study Design: Randomized Block Design. Place and Duration of Study: Department of Horticulture, College of Agriculture, RVSKVV, Gwalior, MP between 2018 - 2019. Methodology:In 2018-19 the study conducted amidst rainy season and Gird agro-climatic context of Madhya Pradesh to evaluate the effect of phytohormones on rooting and establishment of seedless lemon air layers. Experiment consisting nine treatments replicated three times under Randomized Block Design. Treatments comprising of two plant hormones namely IBA and NAA each with four concentration levels i.e. 1250, 2500, 3750 and 5000ppm including control. Plants age were seven years. Results:The results revealed maximal rooting percentage (92.00), number of primary roots (22.72) and secondary roots (49.97), length of primary roots (5.05 cm) and secondary roots (2.25 cm), diameter of primary roots (1.68 mm) and secondary roots (0.84 mm) and dry weight of roots (2.32g) and planted air-layers (89.21 %) were recorded with application of IBA @ 5000ppm. Conclusion:Indole-3-butyric acid performed better than naphthalene acetic acid for promoting rooting and establishment in seedless lemon air-layers. Application of IBA @ 5000ppm significantly increased rooting characters followed by NAA @5000ppm for better establishment of Lemon air layers for its propagation.

EFFECT OF VARIOUS CONCENTRATIONS OF ROOTING HORMONES ON MULTIPLICATION OF BUTTON WOOD TREE (CONOCARPUS ERECTUS L.)

The present investigation entitled “Effect of IBA and NAA on vegetative propagation of button wood tree (Conocarpus erectus L.)” was carried out during 2019 - 2020 at Dr. Y.S.R. Horticultural University, College of horticulture, Anantharajupeta, Y.S.R Kadapa district, Andhra Pradesh. Semi hard wood stem cuttings of Conocarpus erectus were treated with 1000, 2000, 3000 ppm IBA and NAA solutions by quick dip method. Cuttings were then subjected to rooting in a media consisting of sandy soil, farm yard manure, single super phosphate in a ratio of 2:1:1 mixture in black polythene bags. Among all the treatments, number of sprouted cuttings, length of sprout per cutting, diameter of sprout per cutting, number of leaves per cutting, percentage of rooted cutting, number of primary roots per cutting, number of secondary roots per cutting, length of roots per cutting, number of plants transplanted and number of plants established were higher in IBA 3000 ppm.

Transgenerational Induction of Resistance to Phytophthora cinnamomi in Holm Oak

The maternal environment of a tree species can influence the development and resistance of its offspring. Transgenerational induction of resistance is well known in plants but its occurrence in forest tree species has been less reported. Quercus ilex L. (holm oak) is a widespread Mediterranean tree species threatened by the invasive Phytophthora cinnamomi Rands pathogen. The influence of P. cinnamomi on the offspring of infected Q. ilex mother trees has not been studied. This study compared the performance and tolerance to P. cinnamomi of seedlings from non-infected and P. cinnamomi-infected trees. Acorns from Q. ilex trees were collected from five forests. After isolations were conducted in the rhizosphere of several trees, in each forest, three trees were selected as non-infected and three were selected as P. cinnamomi-infected. Forty acorns per tree were weighed and sown under greenhouse conditions, and when plants were aged ~9 months they were challenged with P. cinnamomi. Plant mortality was higher in the offspring of non-infected trees than in the offspring of P. cinnamomi-infected trees (26.2% vs. 21.1%, respectively). Consistently, survival probabilities of seedlings from P. cinnamomi-infected trees were higher than those of seedlings from non-infected trees, particularly in seedlings with reduced growth. Although acorns from healthy Q. ilex trees were heavier than acorns from P. cinnamomi-infected trees, the time to death of inoculated seedlings was not influenced by seed weight. The time to death of seedlings was positively related to belowground mass, particularly to an increased proportion of fine secondary roots. We report transgenerational-induced resistance to P. cinnamomi in Q. ilex triggered by an unknown mechanism independent of acorn mass. Information about the persistence of transgenerational effects in Q. ilex offspring and the influence of these effects on plant fitness is crucial to improve the management and regeneration of this declining species.

Cold stress at seedlings stage of buckwheat optimizes development of both roots and aboveground biomass and limits the excessive vegetative growth interfering with seed formation (an analytical review)

<p>Buckwheat, sown in warmed soil, quickly sprouts, grows and successfully competes with annual weeds. However, such agronomic practice does not always lead to a good grain yield, because a powerful, abundantly flowering buckwheat plants often give only a minimal amount of seeds due to a lack of moisture in the upper layer of soil during flowering. This behavior of buckwheat is described as "overgrowth (with poor seed formation)". This phenomenon is caused by the relative weakness of the root system of this species: the specific feature of buckwheat is a very fast transition to formation of secondary roots, which gives advantages at the first stages of development, but restricts the roots growth later. Buckwheat flowering is stretched in time. First half of this developmental stage which is most important for the grain yield is coincided with the most intensive vegetative growth. The lowered temperature at the seedlings stages slows the growth of the aboveground biomass and accelerates the growth of the roots that at later stages favorably affects the conditions for seeds development and, respectively, the grain yield. It explains why early sowing time is favorable for the grain yield of buckwheat.</p>

Effect of Nitrogen Fertilizer on Growth, Flowering, Fruiting and Nodulation of Three Varieties of Common Bean in the Arid Region of Aïn Naga (Biskra, Algeria)

Field experiments were conducted to investigate the response of common bean (Phaseolus vulgaris L.) to nitrogen fertilizer. The main factor included the fertilizer (Granular Urea 46% N), was made up of two levels: no fertilization (0 kg/plot: control) and fertilization (0.4 kg/plot), while the secondary factor was the variety (three varieties of common bean: Djedida, Nelson and Jalila). The experimental design was a randomized complete block design with split plot arrangement and replicated four times. The effect of fertilization was evaluated during two development stages (flowering and fruiting) for each variety and this on the total dry biomass, the length of the aerial and root parts, as well as on the number of secondary roots. On the other hand, the combined effect of fertilization and variety was studied on some yield parameters per plant, such as the number of flowers, pods, seeds and the harvest index. In addition, the number of nodules at the end of seed maturation was evaluated. The results indicated that the nitrogen fertilizer application significantly reduced the root length, the number of nodules and secondary roots in most of the common bean varieties. However, fertilizer application significantly increased dry matter in both flowering and fruiting stages, for the three studied varieties. Pod number per plant and seed yield was increased by the application of N fertilizer, depending on varieties and the parameters being measured. Djedida and Jalila varieties gave the best yield and can therefore be recommended to farmers. According to our results, the percentage of improvement by N fertilization on one parameter or another does not exceed an average of 20%, compared to the control. Indeed, the effect of fertilization is positive and seems to increase the harvest index by 18% in Djedida and by 20% in Jalila, compared to non-fertilized plants. Unfertilized plants of the variety Nelson showed the highest ability to nodulate.