scholarly journals Disturbance is required for CO2-dependent promotion of woody plant growth in grasslands

2010 ◽  
Vol 37 (6) ◽  
pp. 555 ◽  
Author(s):  
Beth R. Loveys ◽  
John J. G. Egerton ◽  
Dan Bruhn ◽  
Marilyn C. Ball

The relative effects of disturbance (here defined as bare soil), competition for edaphic resources, thermal interference and elevated [CO2] on growth of tree seedlings in grasslands were studied under field conditions. Snow gum (Eucalyptus pauciflora Sieb. ex Spreng.) seedlings were grown in open-top chambers flushed with either ambient or elevated [CO2] from March 2004 to January 2005 (autumn to summer). These seedlings were planted into three treatments (i.e. bare soil, soil covered with straw or soil supporting a sward of live pasture grass) to separate effects of grass on seedling growth into those due to competition with grass for soil resources or to alteration of the thermal environment caused by a grassy surface (Ball et al. 2002). After the first major autumn frost, seedlings growing in competition with grass lost 59% of their canopy area, whereas those growing in bare soil or straw suffered negligible damage. These results reveal the complexity of competitive inhibition of plant growth in which ineffective competition for resources such as soil water enhances the vulnerability of the plant to abiotic stress, in this case frost. Tree seedlings growing in bare soil and straw commenced growth earlier in spring than those growing in competition with grass, where soil moisture was consistently lowest. Under ambient [CO2], growth was greater in bare soil than in straw, consistent with thermal interference, but these differences disappeared under elevated [CO2]. Elevated [CO2] significantly increased biomass accumulation for seedlings growing in bare soil and straw treatments, but not in grass. Thus, elevated [CO2] alleviated apparent thermal interference of seedling growth in spring but did not overcome adverse effects on seedling growth of either competitive reduction in soil resources or competitive enhancement of environmental stress. Nevertheless, elevated [CO2] could promote invasion of grasslands due to enhancement of woody plant growth in bare soil created by disturbances.

Author(s):  
Raeya Jackiw

In response to ecological disturbances, sedge species like Carex pensylvanica form dense monocultures on the forest floor. These “sedge mats” have been shown to severely inhibit plant growth, and limit understory species diversity. In recent years, concern has grown that they may also be restricting the regeneration of economically valuable tree species like sugar maple through belowground competition. To determine if and how Carex pensylvanica may be impacting tree seedling growth through belowground competition I located and exclosed 44 tree seedlings in areas of representatively dense sedge at two forest sites at the Queen’s University Biological Station. I removed sedge from half the plots, and measured soil resource availability and seedling growth response at all plots throughout the growing season. I predicted that sedge would negatively impact the growth of tree seedlings by decreasing the availability of soil resources. I found that the presence of sedge did not affect seedling growth over one growing season, but that it did impact soil resource availability by increasing the availability of surface soil moisture and decreasing the availability of soil nitrate, changes which may have implications for seedling growth beyond the single growing season studied. My results were also site specific, indicating that location is important when managing sedge impact on tree regeneration. Understanding the impact of sedge on tree seedling regeneration is important for predicting changes in the trajectory of forest communities and for informing the management of economically valuable species like sugar maple.


2018 ◽  
Vol 6 (2) ◽  
pp. 73
Author(s):  
Dewa Putu Yoga Gautama ◽  
I Made Anom S. Wijaya ◽  
I Wayan Widia

Pemberian gelombang suara dengan frekuensi tinggi dapat merangsang mulut daun  (stomata) tetap terbuka, akibatnya laju dan efisiensi penyerapan pupuk meningkat yang bermanfaat bagi tanaman. Hasil penggunaan sonic bloom pada tanaman adalah mampu menstimulir metabolisme sel-sel tanaman, sehingga terjadi peningkatan penyerapan nutrisi dan uap air lewat daun yang berpengaruh pada pertumbuhan dan produktivitas tanaman. Tujuan dari penelitian ini yaitu (1) untuk mengetahui pengaruh pemberian musik Gamelan Bali terhadap pertumbuhan dan produktivitas tanaman sawi pakcoy dan (2) untuk menentukan jenis musik Gamelan Bali yang memberikan pertumbuhan dan produktivitas sawi pakcoy yang terbaik. Penelitan ini menggunakan tanaman sawi pakcoy (Brassica Rafa L.).  Perlakuan yang diberikan  dalam penelitian adalah pemberian musik gamelan bali dengan nuansa musik yang berbeda. Perlakuan 1 menggunakan musik gamelan Angklung, Perlakuan 2 menggunakan musik gamelan Semarpagulingan dan Perlakuan 3 menggunakan musik gamelan Gong Kebyar. Data yang diperoleh dianalis ANOVA dengan program IBM SPSS 20. Variabel yang diamati yaitu tinggi tanaman, luas kanopi daun tanaman, tingkat kehijauan daun tanaman, dan berat kering. Hasil penelitian menunjukan bahwa pemberian musik gong kebyar menghasilkan nilai tertinggi pada variabel tinggi tanaman, luas kanopi daun, tingkat kehijauan daun, dan berat kering yang  masing menghasilkan nilai yaitu yaitu 29,98 cm, 1684 cm2, 186,79, dan 68,61 gr. Pemberian musik memberikan pengaruh yang positif dan berbeda nyata pada pertumbuhan tanaman sawi pakcoy. Semakin tinggi frekuensi musik yang diberikan maka semakin baik pertumbuhan tanaman sawi pakcoy yang dihasilkan.  High frequency sound waves can stimulate the mouth of leaf (stomata) remains opened.The stomata remains open leading to efficient absorption of fertilizer. The purposes of this research were (1) to find out the effect of Balinese instrument music on the growth and productivity of pakcoy mustard plant and (2) to determine the type of Balinese instrument music that gives the best growth and productivity of mustard pakcoy. The treatment of this research was the application of Balinese instrument music with different musical nuances for 3 hours. Treatment 1 was using Angklung instruments music, treatment 2 was using Semarpagulingan instrument music and treatment 3 using Gong Kebyar instrument music. The obtained data was analized by ANOVA with the IBM SPSS 20 program. The observed variables include plant height, canopy area of plant leaf, green leaves level and dry weight. The results showed that Gong Kebyar instrument music application produces the highest value of 29.98 on the height of the plant variables, the widest value of 1684 cm2  on the canopy area variables, the biggest value that is 68,61 gr on the dry weight variables and the largest value of 186.79 on the green leaves level variables. Balinese instrument music application effect to the growth of pakcoy mustard plant. The best plant growth was the plant with gong kebyar instrument music application from all observed variables.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 939
Author(s):  
Yoko Watanabe ◽  
Kiyomi Hinata ◽  
Laiye Qu ◽  
Satoshi Kitaoka ◽  
Makoto Watanabe ◽  
...  

To elucidate changes in the defensive traits of tree seedlings under global environmental changes, we evaluated foliar defensive traits of the seedlings of successional trees, such as beech, oak, and magnolia grown in a natural-light phytotron. Potted seedlings were grown under the combination of two CO2 concentrations (360 vs. 720 ppm) and two nitrogen (N) treatments (4 vs. 15 kg N ha−1 yr−1) for two growing seasons using quantitative chemical analyses and anatomical method. We hypothesized that the effects of CO2 and N depend on the successional type, with late successional species providing greater defense of their leaves against herbivores, as this species exhibits determinate growth. Beech, a late successional species, responded the most to both elevated CO2 concentration (eCO2) and high N treatment. eCO2 and low N supply enhanced the defensive traits, such as the high leaf mass per area (LMA), high carbon to N ratio (C/N ratio), and increase in the concentrations of total phenolic and condensed tannin in agreement with the carbon–nutrient balance (CNB) hypothesis. High N supply decreased the C/N ratio due to the high N uptake in beech leaves. Oak, a mid–late successional species, exhibited different responses from beech: eCO2 enhanced the LMA, C/N ratio, and concentration of total phenolics of oak leaves, but only condensed tannin increased under high N supply. Magnolia did not respond to all treatments. No interactive effects were observed between CO2 and N supply in all species, except for the concentration of total phenolics in oak. Although the amounts of phenolic compounds in beech and oak varied under eCO2 and high N treatments, the distribution of these compounds did not change. Our results indicate that the changes in the defensive traits of forest tree species under eCO2 with N loading are related to the successional type.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mulla S. Ayesha ◽  
Trichur S. Suryanarayanan ◽  
Karaba N. Nataraja ◽  
Siddegowda Rajendra Prasad ◽  
Ramanan Uma Shaanker

Pre-sowing seed treatment with systemic fungicides is a firmly entrenched practice for most agricultural crops worldwide. The treatment is intended to protect the crop against seed- and soil-borne diseases. In recent years, there is increasing evidence that fungicidal applications to manage diseases might inadvertently also affect non-target organisms, such as endophytes. Endophytes are ubiquitously present in plants and contribute to plant growth and development besides offering resistance to biotic and abiotic stresses. In seeds, endophytes may play a role in seed development, seed germination, seedling establishment and crop performance. In this paper, we review the recent literature on non-target effects of fungicidal applications on endophytic fungal community and discuss the possible consequences of indiscriminate seed treatment with systemic fungicide on seed endophytes. It is now well recognized that endophytes are ubiquitously present in all parts of the plant, including the seeds. They may be transmitted vertically from seed to seed as in many grasses and/or acquired horizontally from the soil and the environment. Though the origins and evolution of these organisms in plants are a matter of conjecture, numerous studies have shown that they symbiotically aid in plant growth and development, in nutrient acquisition as well in protecting the plants from abiotic and biotic stresses. Against this background, it is reasonable to assume that the use of systemic fungicides in seed treatment may not only affect the seed endophytes but also their attendant benefits to seedling growth and establishment. While there is evidence to indicate that fungicidal applications to manage plant diseases also affect foliar endophytes, there are only few studies that have documented the effect of seed treatment on seed-borne endophytes. Some of the convincing examples of the latter come from studies on the effect of fungicide application on rye grass seed endophyte AR37. More recently, experiments have shown that removal of seed endophytes by treatment with systemic fungicides leads to significant loss of seedling vigour and that such losses could be partially restored by enriching the seedlings with the lost endophytes. Put together, these studies reinforce the importance of seed endophytes to seedling growth and establishment and draw attention on how to trade the balance between the benefits of seed treatments and the direct and indirect costs incurred due to loss of endophytes. Among several approaches, use of reduced-risk fungicides and identifying fungicide-resistant endophytes are suggested to sustain the endophyte contribution to early seedling growth.


HortScience ◽  
2017 ◽  
Vol 52 (12) ◽  
pp. 1650-1654
Author(s):  
Margarita Pérez-Jiménez ◽  
Almudena Bayo-Canha ◽  
Gregorio López-Ortega ◽  
Francisco M. del Amor

Enrichment with CO2 and a commercial mix of plant growth regulators were tested to improve the plant quality and survival of pregerminated cherry tree seedlings. Pregerminated seeds were transferred from a cold chamber to a climatic chamber where the CO2 was set at 800 µmol·mol−1 CO2 or at the ambient CO2 concentration. Also, half of the plants were sprayed with the mix of plant growth regulators and disposed randomly. The experiment lasted 18 days and physiological measurements, such as plant physiological status and growth, number of leaves, net CO2 assimilation (ACO2), internal CO2, stomatal conductance, and transpiration, were taken every 4 days. Also, at the end of the experiment, other parameters—such as total leaf area, photosynthetic pigments, soluble sugars, and starch—were recorded or quantified. During the experiment, plants cultured under CO2 enrichment exhibited a rapid increase in their photosynthetic rates, height, and leaf number; the commercial mix also increased plant height but inhibited leaf expansion and growth. At the end of the experiment, the amounts of starch and soluble sugars had increased in the plants grown under elevated CO2, compared with those plants grown in control conditions or with the commercial mix. Thus, culture at elevated CO2 achieved higher percentages of plant survival and of plants in active growth. We suggest that CO2 plays an important role—by increasing ACO2, water use efficiency, soluble sugars, and starch—which results in plants that are physiologically more prepared for transfer to the field.


2020 ◽  
Vol 12 (18) ◽  
pp. 7457
Author(s):  
Jie Xu ◽  
Yi Liu ◽  
Chao Zhu ◽  
Honglei Jia ◽  
Changyan Tian ◽  
...  

Halophytes have been studied as a model for morphological traits of adaptation to saline environments. However, little information has been given on plant growth, chlorophyll fluorescence responses, and change of ion content in halophytes grown in an aniline–salinity coexistent environment. This study hypothesized that aniline could induce alterations in plant growth, chlorophyll fluorescence, and ion content in Suaeda salsa, but salinity could promote the tolerance of halophytes to aniline. A 6 (aniline) × 3 (NaCl) factorial experiment (for a total of 18 treatments) was conducted to test the above hypothesis. After 30 d of cultivation, roots and shoots were harvested separately to analyze the effects of salinity on the seedling growth under aniline stress. Biomass accumulation was inhibited by aniline treatment, and the inhibition was significantly alleviated by 200 mM NaCl. The change in chlorophyll fluorescence in leaves with aniline stress was moderated by the addition of NaCl. The removal efficiency of aniline was significantly enhanced by moderate salinity. Aniline stress decreased the accumulation of Mg2+, but various concentrations of NaCl increased the accumulation of Mg2+, especially with 200 mM NaCl in both roots and shoots. Both aniline and salinity decreased the content of Ca2+. There was a negative correlation between the K+ and NaCl concentrations and between the Cl− and aniline concentrations. Our results indicated that Suaeda salsa may be suitable for the remediation of salinity and aniline-enriched wastewater.


Oikos ◽  
2013 ◽  
Vol 123 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Glenn R. Moncrieff ◽  
Simon Chamaillé-Jammes ◽  
William J. Bond

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