scholarly journals Substrate Type Influences the Structure of Epiphyte Communities and the Growth of Posidonia oceanica Seedlings

2021 ◽  
Vol 12 ◽  
Author(s):  
Davide De Battisti ◽  
Elena Balestri ◽  
Giuseppina Pardi ◽  
Virginia Menicagli ◽  
Claudio Lardicci

Epiphytes colonizing adult seagrasses highly contribute to seagrass ecosystem functioning and plant growth. Yet, little information exists on epiphytic communities developing on seagrass seedlings. Moreover, for some species our knowledge about seedling performance is limited to early establishment phases, and the role of substrate type in affecting their growth is still unclear. These are considerable knowledge gaps, as seedlings play an important role in meadow expansion and recovery from disturbance. In this study, seedlings of Posidonia oceanica, a keystone species of the Mediterranean, were grown in a shallow (1.5 m deep) coastal area along the Tuscany coast (Italy). After five years of growth (July 2009), seedlings were collected and, through multivariate analysis, we examined whether the epiphytic communities of leaves (both internal and external side) and rhizomes, as well as the growth characteristics differed between rock and sand substrate. The epiphytic communities of seedlings largely reflected those found on adult shoots. Epiphyte cover was similar between the two leaf sides, and it was higher on seedlings grown on rock than on sand, with encrusting algae dominating the community. No differences in epiphyte cover and community structure on rhizomes were found between substrates. Seedling growth characteristics did not differ between substrates, apart from the number of standing leaves being higher on rock than on sand. No correlation was found among epiphyte communities and seedling growth variables (i.e., leaf area, maximum leaf length, number of leaves, total number of leaves produced, rhizome length, total biomass, and root to shoot biomass ratio). Results indicate that epiphytes successfully colonize P. oceanica seedlings, and the surrounding micro-environment (i.e., substrate type) can influence the leaf epiphytic community. This study provides new valuable insights on the biological interactions occurring in seagrass ecosystems and highlights the need for better understanding the effects of seedling epiphytes and substrate on the formation of new meadows.

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 294
Author(s):  
Ma Claudia Castañeda-Saucedo ◽  
Ernesto Tapia-Campos ◽  
Jessica del Pilar Ramírez-Anaya ◽  
Jaqueline Beltrán

Stevia is an important non-caloric sweetener that has health-beneficial properties. The objective is to evaluate growth, development, and rooting of stevia plants during different seasons of the year using growth hormones. Eight experiments were set up in Ciudad Guzman, Jalisco, Mexico, with three treatments (T): T1, indol-3 butyric acid (IBA) 7.4 mM; T2, alphanaphthylacetamide (ANA) 6.4 mM + IBA 0.3 mM; and T3, control. The variables evaluated were rooted plantlets, plant height, root length, number of leaves, stem diameter, leaf dry weight, stem dry weight, root dry weight, leaf area, shoot biomass, total biomass, as well as development and growth indexes. Four samplings were conducted in each experiment. The results show that the most appropriate months for propagating stevia cuttings are February, March, April, May, and July, when 96% to 99% of the cuttings rooted. The hormones had the best results related to production of root development. The control was outstanding only in variables related to production of shoot biomass and not to root development. It is concluded that stevia can be propagated vegetatively using cuttings treated with IBA 7.4 mM or ANA 6.4 mM + IBA 0.3 mM, preferable in the period from February to July, with the exception of June.


2017 ◽  
Vol 23 (1) ◽  
Author(s):  
ASTHA GUPTA ◽  
RAMAKANT TEWARI ◽  
S. L. MEENA

The study was conducted at National Research Centre for Agroforestry, Jhansi (U.P.) India. Fresh seeds of Bahera were sun dried, depulped and subjected to three soil media [Red soil+FYM (1:1), Black soil+FYM (1:1) and Red+Black soil+FYM(1:1:1)] and three sowing depths (2.0, 3.0 and 4.0cm) for seed germination in April month. Results indicated that maximum seed germination (94%) was obtained in Red soil + FYM mediaat 2.0cm sowing depth. This treatment recorded quickest initiation and completion of germination(11and 21 days respectively). Seedling growth in terms of plant height, collar diameter and canopy spread and number of leaves was maximum under Red soil+FYM and minimum under Black soil+FYM. In general, plant growth reduced with increase in depth of sowing. However, the differences among various treatments were largely non-significant. Total biomass air dry ranged between 10.52 to 13.90g/plant across the treatments at 6 months stage.


2021 ◽  
Vol 25 (6) ◽  
pp. 969-975
Author(s):  
M.K. Peter ◽  
SIN Agera ◽  
J.I. Amonum

This study investigated the effects of potting media on seed germination and early seedling growth of Pterocarpus erinaceus Poir at the Forestry Nursery in Jos, Nigeria. Using Completely Randomized Design (CRD) with three replicates, laboratory-tested soil samples, top soil, sharp sand, sharp sand + top soil, sharp sand + top soil + cow dung and sharp sand + top soil + poultry droppings were used in various combinations to assess the growth parameters of P. erinaceus (germination percentage, emergence, plant height, number of leaves, length of leaves and stem diameter) for 12 weeks. Descriptive and inferential statistics were employed to analyze collected data. Result indicated that sharp sand + top soil + poultry droppings had the highest nitrogen concentration (2.19%), sharp sand + top soil + cow dung (2.07%), sharp sand + top soil (1.50%), top soil (0.72%) and Sharp sand (0.38%). Potting media with poultry droppings recorded an overall higher percentage germination of 42.9% by the end of the germination period. Analysis of variance (ANOVA) of collected data on combined soil aggregate on growth parameters indicated a significant (p<0.05) difference in plant height, number of leaves, leaf length and stem diameter. Potting with poultry dropping gave the best potting media growth results when compared to other treatments that enhanced seed germination and seedling growth of P. erinaceus. This superior observation of the poultry droppings incorporated potting mixtures over the cow dung provides an outstanding potentials to enhance P. erinaceus plantation establishment. Consequently, recommended for raising seedlings in the nursery as well as ensuring sustainable management.


Author(s):  
J. Ambujavalli ◽  
K. Santhiya ◽  
K. Rohini ◽  
V. Kumaresan

Aim: To study the effect of shade net on the growth characteristics of two medicinal plants viz., Tulsi and Indian Borage in terms of plant height, number of leaves, leaf area and flowering in relation to open condition. Place and Duration of Study: Lawspet, Puducherry, India between June 2018 and October 2018. Methodology: Tulsi and Indian Borage plants were grown in similar type of soil. The potted plants were kept in open, 35% and 75% shade net conditions and studied for 3 months. The plant height, number of leaves, and leaf area were measured including number of inflorescence branches for Tulsi. Results: The average air temperature was lower under shade net. Relative humidity was more in shade net conditions with maximum in 75% shade and least in open conditions. The number of leaves of Tulsi and Indian Borage recorded was maximum when grown under 35% shade and least in open conditions. Plant height was maximum in 75% shade for Tulsi and 35% shade in Indian Borage and least in open conditions on both the cases. Leaf area was maximum for both Tulsi and Indian Borage in 75% shade. Conclusion: Growth of the two medicinal plants was influenced by the microclimate conditions. The present study shows that the medicinal plants can be grown in shade net conditions to increase the yield of medicinally useful parts.


2020 ◽  
Vol 115 (2) ◽  
pp. 247
Author(s):  
Daniel B. ADEWALE ◽  
Beatrice A. NDUKA

<p>The probable role of within-pod microenvironment on seed sizes, seedling vigour and biomass yield of four cocoa genotypes was investigated for two years. The respective main, sub and sub-sub plots in the split-split plot experimental design were years, genotypes and within-pod bean positions. Data were taken on cocoa bean length, width and thickness after each pod was opened. Four weekly periodic data were obtained for plant height (PH), stem girth (SG) and number of leaves (NOL); root and shoot biomass yield were also recorded. Analysis of variance revealed significant (p ≤ 0.05) bean position, genotypes, years and some interaction on the studied traits. Means of the levels of the three factors differed significantly (p ≤ 0.05). Proximal, middle and distal positions were distinct within-pod microenvironments. The pod middle cavity housed the longest, widest and heaviest beans. Trend analysis of the growing sequences of NOL, PH and SG by the four genotypes differed with bean locations. For bean length, GGE biplot respectively identified CRIN Tc1, CRIN Tc2 and CRIN Tc3 as the best genotype for middle, proximal and the distal positions. The intra-locular space within the pod enhanced differential seed development and maturation; this was evident in the seedling vigour.</p>


2021 ◽  
Author(s):  
Xuemei Wang ◽  
Bangguo Yan ◽  
Liangtao Shi ◽  
Gangcai Liu

Abstract Biotic plant-soil feedback has been widely studied, and may be particularly important in resource-poor areas. However, the roles of soil nutrient cycling in affecting plant growth in this process still remained unclear. The aim of this study was to explore the roles of soil biota in regulating nutrient cycling by conducting a two-phase feedback experiment in a dry-hot valley, with a conditioning phase during which there were Dodonaea viscosa or no D. viscosa growing in the soil, and a feedback phase in which the effect of the conditioned soil biota on D. viscosa performance was measured. The growth of D. viscosa significantly reduced soil N after the conditioning phase. However, D. viscosa showed a positive plant-soil feedback. In the feedback phase, the D. viscosa conditioned soil promoted the stem diameter, leaf area, and leaf dry mass content of D. viscosa. Total biomass was also significantly higher in D. viscosa conditioned soil than that in not conditioned soil. In contrast, soil sterilization had a negative effect on the growth of D. viscosa, with a significant reduction in plant biomass, especially in D. viscosa conditioned soil, and soil sterilization significantly increased the root: shoot biomass ratio and litter mass. Furthermore, we showed that although the biota-driven changes in enzyme activities correlated with the leaf N and P amount especially P amount, the enzyme activity was not the main reason to promote D. viscosa growth in the conditioned soil.


2014 ◽  
Vol 1073-1076 ◽  
pp. 1099-1103
Author(s):  
Guo Jun Zhang ◽  
Cheng He Wang ◽  
Min Hua Zhao ◽  
Wan Qi Wang ◽  
Jun Ming Yang

Seedling growth traits of 24 provenances of Larix principis-rupprechtii were analyzed to select superior provenances. Variance and correlation on height, basal diameter, root length, root and stem fresh weight of 1-year old and 2-year old seedlings of those provenances were analyzed. Then correlation coefficients between these growth traits and membership value of height and basal diameter of 24 provenances were carried on. Results showed that variance on growth traits of 1-year old seedlings among 24 provenances were only significant for height, but for basal diameter, height, root and stem fresh weight of 2-year old seedlings. Based on correlation coefficients between growth traits, height and basal diameter were selected for comprehensive evaluation. The top 5 provenances of Larix principis-rupprechtii were Neimeng Balinzuo, Hebei Weichang 1-21, 7-46, 8-75, and Beijing, according to average of membership value of height and basal diameter.


HortScience ◽  
2018 ◽  
Vol 53 (5) ◽  
pp. 710-714 ◽  
Author(s):  
Huixia Li ◽  
Zhujun Chen ◽  
Ting Zhou ◽  
Yan Liu ◽  
Sajjad Raza ◽  
...  

The interaction between potassium (K) and magnesium (Mg) in plants has been intensively studied. However, the responses of different tomato (Solanum lycopersicum L.) cultivars to high K levels at low temperatures remained unclear. Herein, a complete randomized hydroponic experiment was conducted to evaluate the effects of temperature (25 °C day/18 °C night vs. 15 °C day/8 °C night) and K concentrations (156 mg·L−1 vs. 468 mg·L−1) on the growth and Mg nutrition of tomato cultivars Gailiangmaofen (MF) and Jinpeng No. 1 (JP). Compared with the control temperature (25 °C day/18 °C night), the low temperature decreased total biomass, shoot biomass, and Mg uptake in shoot by 17.3%, 24.1%, and 11.8%, respectively; however, the root/shoot ratio was increased. High K had no significant effect on plant growth or biomass compared with the control K concentration (156 mg·L−1); however, Mg concentrations and uptake in shoot were significantly lower under high-K treatment. Significant difference was observed for K uptake, but not for Mg uptake, between the two cultivars. There was no significant interaction between temperature and high K on Mg uptake of tomato, so a combined stress of low temperature and high K further inhibited Mg uptake and transport. Low temperature and high K increased the risk of Mg deficiency in tomato.


2020 ◽  
Vol 48 (1) ◽  
pp. 234-244
Author(s):  
Edinéia M.M. BARTIERES ◽  
Silvana P.Q. SCALON ◽  
Daiane M. DRESCH ◽  
Edvânia A.S. CARDOSO ◽  
Mailson V. JESUS ◽  
...  

In this research it was hypothesized that Campomanesia xanthocarpa can overcome some level of water deficiency by adjusting physiological parameters and that shading minimizes the water deficit effects while maintaining elevated photosynthetic rates and relative water content of the leaves and makes a resumption of metabolism and growth when the water supply is normalized. The seedlings were submitted to two water regimes (continuous irrigation - CI and intermittent irrigation - II), three shading percentages (0, 30 and 70%) and six evaluation times (Start - T0, 1st Photosynthesis Zero - 1st P0, 1st Recovery - 1st REC, 2nd Photosynthesis Zero - 2nd P0, 2nd Recovery - 2nd REC and END). Plants under water deficit at 0% shading led to a reduction in photosynthetic metabolism, relative water content (RWC), leaf area, number of leaves, and height, especially during the stress periods 1st and 2nd P0. The 30 and 70% shading mitigated the stressful effect of water deficit on C. xanthocarpa seedlings. The results did not confirm the hypothesis that C. xanthocarpa seedlings are intolerant to water deficit since, although sensitive, they presented a potential for recovery of photosynthetic and growth characteristics under all cultivation conditions. It was concluded that that shading minimizes the stressful effects of water deficit.


2019 ◽  
Vol 37 ◽  
Author(s):  
A.A.M. BARROSO ◽  
P.S.H. FERREIRA ◽  
D. MARTINS

ABSTRACT: Weeds reduce the productive potential of crops. Plants of the Ipomoea genus, besides competing for water, light, space and nutrients, create problems in crop harvests due to their volatile stems. The objective of this work was to evaluate the growth and development of five Ipomoea species. For such, Ipomoea grandifolia, Ipomoea hederifolia, Ipomoea nil, Ipomoea purpurea and Ipomoea quamoclit plants were analyzed during the summer and winter season. Five destructive and periodic growth evaluations were carried out for each study, where leaf number, leaves, stems, roots and the total biomass were analyzed. Phenological stages of the plant development were also evaluated for emergence, flowering and maturation sub-periods by degree-days, totalizing five treatments, conducted in a completely randomized design with four replicates. The phenology averages were analyzed according to the Hess scale, and the growth data through nonlinear regressions. I. quamoclit and I. grandifolia obtained the highest number of leaves in the summer and the winter, respectively. I. nil obtained greater accumulation of leaf and stem dry biomass in both seasons. I. grandifolia obtained greater root development in both periods. I. quamoclit presented reduced cycle times when compared to the other species, especially I. hederifolia and I. grandifolia, which presented larger cycles. Based on the results, I. grandifolia probably shows greater interference with agricultural crops due to high root growth, high leaf production and longer cycle. Shorter-cycle species, such as I. quamoclit, when present, should require shorter residual control periods.


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