Shoot Matter Research Articles

Impact of goat manure application on growth of wild watermelon under shade house cultivation

The continuous use of inorganic fertilizers in agriculture poses detrimental effects on soil health and future crop yields. Therefore, alternative sources of plant nutrients that are environmentally friendly and cost-effective for use in crop production, especially with the escalating cost of inorganic fertilizers, are necessary. A shade-house study was designed to determine the effect of different quantities of goat manure applications on growth attributes and yield of wild watermelon (Citrullus lanatus subsp.). A randomized complete block design (RCBD) was used to arrange the treatments, with fourteen (14) replications (n = 84). Six (6) treatments consisting of various quantities (v/v) of river sand, Hutton soil, and goat manure (T0 -1:3:0, T1 -1:3:1, T2 -1:3:2, T3 -1:3:3, T4 -1:3:4, and T5 -1:3:3) were used, with T0 -1:3:0 constituting the control. Treatments had a highly significant (P ≤ 0.01) effect on dry shoot mass (65%), fruit weight (75%), and fruit diameter (75%) except for the dry root mass (44%), vine length (47%), chlorophyll (47%), number of fruit (27%) and stem diameter (22%) of wild watermelon plants. Dry shoot mass was the highest (11.14 g) in T4 -1:3:4, and the lowest dry shoot mass (6.57 g) was obtained in T1 -1:3:1 when compared to the control. The fruit fresh weight of the wild watermelon was reduced in all the treatments, when compared to the control. The biggest fruit diameter (66.66 mm) was observed in T4 -1:3:4, and the lowest (14.4 mm) was observed in T5 -1:3:5. In conclusion, T4 -1:3:4 enhanced greater vegetative growth (dry shoot matter) and yield attributes (fruit diameter and weight) of the wild watermelon.

Genome-Wide Identification, Characterization, and Expression Analysis of the HD-Zip Gene Family in Lagerstroemia for Regulating Plant Height.

The Homeodomain leucine zipper (HD-Zip) family of transcription factors is crucial in helping plants adapt to environmental changes and promoting their growth and development. Despite research on the HD-Zip family in various plants, studies in Lagerstroemia (crape myrtle) have not been reported. This study aimed to address this gap by comprehensively analyzing the HD-Zip gene family in crape myrtle. This study identified 52 HD-Zip genes in the genome of Lagerstroemia indica, designated as LinHDZ1-LinHDZ52. These genes were distributed across 22 chromosomes and grouped into 4 clusters (HD-Zip I-IV) based on their phylogenetic relationships. Most gene structures and motifs within each cluster were conserved. Analysis of protein properties, gene structure, conserved motifs, and cis-acting regulatory elements revealed diverse roles of LinHDZs in various biological contexts. Examining the expression patterns of these 52 genes in 6 tissues (shoot apical meristem, tender shoot, and mature shoot) of non-dwarf and dwarf crape myrtles revealed that 2 LinHDZs (LinHDZ24 and LinHDZ14) and 2 LinHDZs (LinHDZ9 and LinHDZ35) were respectively upregulated in tender shoot of non-dwarf crape myrtles and tender and mature shoots of dwarf crape myrtles, which suggested the important roles of these genes in regulate the shoot development of Lagerstroemia. In addition, the expression levels of 2 LinHDZs (LinHDZ23 and LinHDZ34) were significantly upregulated in the shoot apical meristem of non-dwarf crape myrtle. These genes were identified as key candidates for regulating Lagerstroemia plant height. This study enhanced the understanding of the functions of HD-Zip family members in the growth and development processes of woody plants and provided a theoretical basis for further studies on the molecular mechanisms underlying Lagerstroemia plant height.

Ethylene Action Inhibition Improves Adventitious Root Induction in Adult Chestnut Tissues.

Phase change refers to the process of maturation and transition from the juvenile to the adult stage. In response to this shift, certain species like chestnut lose the ability to form adventitious roots, thereby hindering the successful micropropagation of adult plants. While auxin is the main hormone involved in adventitious root formation, other hormones, such as ethylene, are also thought to play a role in its induction and development. In this study, experiments were carried out to determine the effects of ethylene on the induction and growth of adventitious roots. The analysis was performed in two types of chestnut microshoots derived from the same tree, a juvenile-like line with a high rooting ability derived from basal shoots (P2BS) and a line derived from crown branches (P2CR) with low rooting responses. By means of the application of compounds to modify ethylene content or inhibit its signalling, the potential involvement of this hormone in the induction of adventitious roots was analysed. Our results show that ethylene can modify the rooting competence of mature shoots, while the response in juvenile material was barely affected. To further characterise the molecular reasons underlying this maturation-derived shift in behaviour, specific gene expression analyses were developed. The findings suggest that several mechanisms, including ethylene signalling, auxin transport and epigenetic modifications, relate to the modulation of the rooting ability of mature chestnut microshoots and their recalcitrant behaviour.

High-resolution gene expression atlases of two contrasting major Greek olive (Olea europaea L.) tree cultivars for oil and table olive production.

Olive (Olea europea L.) is one of the most economically important tree crops worldwide, especially for the countries in the Mediterranean basin. Given the economic and nutritional importance of the crop for olive oil and drupe production, we generated transcriptional atlases for the Greek olive cultivars "Chondrolia Chalkidikis" and "Koroneiki" which have contrasting characteristics in terms of fruit development, oil production properties, and use. Our analysis involved 14 different organs, tissue types, and developmental stages, including young and mature leaves, young and mature shoots, open and closed flowers, young and mature fruits (epicarp plus mesocarp), young and mature endocarps, stalks, as well as roots. The developed gene expression atlases and the associated resources offer a comprehensive insight into comparative gene expression patterns across several organs and tissue types between significant olive tree cultivars. The comparative analyses presented in this work between the "Koroneiki" cultivar, which performs better in olive oil production, and the "Chondrolia Chalkidikis," which grows larger fruits, will be essential for understanding the molecular mechanisms underlying olive oil production and fruit shape and size development. The developed resource is also expected to support functional genomics and molecular breeding efforts to enhance crop quality and productivity in olive trees. The transcriptome data were generated using paired-end Illumina Next-Generation Sequencing technologies. The sequencing yielded approximately 13 million reads per sample for "Chondrolia Chalkidikis" and around 24 million reads per sample for "Koroneiki." The transcriptomes were comparatively analyzed to reveal tissue-specific and differentially expressed genes and co-expression gene modules within and between cultivars. The comparative analysis unveiled tissue-specific and differentially expressed genes within and between cultivars. Hierarchical gene clustering revealed intra- and inter-cultivar expression patterns, particularly for the endocarp and fruit tissues relevant to olive oil production and fruit development. Additionally, genes associated with oil production and fruit size/shape development, including those in fatty acid metabolism and developmental regulation, were identified. To facilitate accessibility, the GrOlivedb (www.GrOlivedb.com) database was developed, housing the comprehensive transcriptomic data for all of the analyzed organs and tissue types per cultivar. This resource will be a useful molecular tool for future breeding studies in olive oil production and fruit development and a valuable resource for crop improvement.

Arabidopsis response to copper is mediated by density and root exudates: Evidence that plant density and toxic soils can shape plant communities.

Plants grown at high densities show increased tolerance to heavy metals for reasons that are not clear. A potential explanation is the release of citrate by plant roots, which binds metals and prevents uptake. Thus, pooled exudates at high plant densities might increase tolerance. We tested this exclusion facilitation hypothesis using mutants of Arabidopsis thaliana defective in citrate exudation. Wild type Arabidopsis and two allelic mutants for the Ferric Reductase Defective 3 (FRD3) gene were grown at four densities and watered with copper sulfate at four concentrations. Plants were harvested before bolting and dried. Shoot biomass was measured, and shoot material and soil were digested in nitric acid. Copper contents were determined by atomic absorption. In the highest-copper treatment, density-dependent reduction in toxicity was observed in the wild type but not in FRD3 mutants. For both mutants, copper concentrations per gram biomass were up to seven times higher than for wild type plants, depending on density and copper treatment. In all genotypes, total copper accumulation was greater at higher plant densities. Plant size variation increased with density and copper treatment because of heterogeneous distribution of copper throughout the soil. These results support the hypothesis that citrate exudation is responsible for density-dependent reductions in toxicity of metals. Density-dependent copper uptake and growth in contaminated soils underscores the importance of density in ecotoxicological testing. In soils with a heterogeneous distribution of contaminants, competition for nontoxic soil regions may drive size hierarchies and determine competitive outcomes.

Interação de plântulas de soja com rizobactérias benéficas

Beneficial rhizobacteria are multifunctional microorganisms that stimulate plant growth through direct mechanisms such as the solubilization of phosphorus and potassium present in soil minerals, biological nitrogen fixation and production of plant hormones. The objective of this study was to determine the effect of beneficial rhizobacteria on the initial development, promoting growth and resistance of soybean seedlings, aiming not only for increased production but also for agricultural sustainability through the maximization of biological efficiency in the early development of soybean seedlings. The experiment, under controlled conditions, was conducted in a completely randomized design, with four treatments and ten replications. The treatments consisted in the microbiolization of soybean seeds with: 1. Control (without microorganism); 2. Serratia marcenses (BRM 32114); 3. Bacillus spp. (BRM63573) and 4. BRM 32114 + (BRM63573). After the microbiolization of the seeds, they were sown and placed to germinate, after 12 days, the seedlings were harvested and divided into shoots and roots. The roots were washed and photographed with digital camera. The images were analyzed and determined length, diameter, surface area and volume of roots. Then, root and shoot were dried and weighed for biomass determination. Co-inculation, BRM 32114+ BRM63573, promoted greater robustness of the root system of soybean seedlings with increased length (16.2%), diameter (22.5%), volume (43.4%) and dry biomass (29.7%). The dry matter of shoots and total soybean seedlings was superior to the control treatment in all treatments with rhizobacteria. Therefore, plant growth promoting

Suficiência amostral, correlação e análise de trilha em ervilha forrageira

ABSTRACT: It is important to determine the number of plants to be evaluated to allow accurate inferences about the traits under evaluation. Investigating the linear relations among traits is important for identifying traits for indirect selection. So, the objectives of this study were to determine the sample size (number of plants) necessary to estimate the means of forage pea traits and to investigate the relations among the traits. Experiments were carried out in 2021 with three sowing dates (May 3, May 26 and July 13). Five hundred plants were randomly sampled, 100 plants in each of the five evaluation dates (June 25, August 30, July 24, September 17, September 16). In these 500 plants, the traits plant height, number of branches, number of nodes, number of leaves, number of pods, fresh matter of leaves, fresh matter of stems, fresh matter of pods, fresh matter of shoots, dry matter of leaves, dry matter of stems, dry matter of pods, and dry matter of shoots, were evaluated. The sample size was calculated to estimate the means of these traits, based on Student’s t-distribution, and the relations among traits were investigated through correlation and path analysis. In an experiment, to estimate the means of these 13 traits of forage pea, with an estimation error of approximately 10% of the mean, 99 plants per treatment should be sampled. The numbers of pods and leaves have a positive linear relations with fresh and dry matter of shoots.

The Effect of Planting Deadlines on the Thickness of the Rice Seedling

In this article, a scientific study was carried out on the seedling thickness of the shawl. Experiments were carried out in the conditions of two regions, and elements were studied that ensure the seedling thickness of the shawl in different climates. The dependence of the size of the seeds of the shoot of the plant at the beginning of the generative period in the middle of the shoot phase will be equal to the number of spikes on the mature shoot. High water temperatures and a lack of nitrogen lead to small rovaks and a decrease in the number of grains. The intensity of clumping is considered a varietal sign. But it depends on the irrigation regime, nitrogen nutrition, the amount of oxygen on the soil surface, air temperature, water temperature, Bush thickness. Under production conditions, the yield coefficient corresponds to an average of 1.8-2.2 single plants. The budding phase begins with the formation of additional stems in plants. The formation of a clump joint in a single plant was controlled by lowering the water level during the clumping period, providing light to reach the clump joint of the plant.

Growth of soybean plants cultivated in soil and fertilized with silicon.

Although silicon is not considered an essential element, in some crops such as soybeans, its supply can stimulate plant development and plant production. The growth of soybean cultivars in Cerrado soil subjected to the application of silicon doses was studied. The experiment was conducted in a greenhouse at the Instituto Federal do Amapá - IFAP/Campus Agrícola Porto Grande. The experimental design was completely randomized, arranged in a 5x2 factorial scheme, with four replications. The factors consisted of the control treatment (without Si) and four doses of Si (250, 500, 750 and 1000 mg pot-1 of SiO2), and two soybean cultivars (BRS Tracajá and FTS Paragominas). Growth variables were analyzed, such as: plant height, stem diameter; and dry matter of shoots and roots. Silicon influenced the increase in height when evaluating the cultivars and isolated doses, the same behavior was observed in the dry matter production of the aerial part and total. The element silicon helps in the improvement and gain in height and other evaluated agronomic characteristics, but studies with this element must be more applied, to obtain the answer for other variables and study conditions.

The effect of zinc application on growth and alleviating shoot concentration of cadmium in durum wheat plant growth under conditions of salt and cadmium stress

A study was conducted in a greenhouse to investigate the effect of the combination of cadmium (Cd) and salinity (NaCl) stress in zinc (Zn) deficiency on growth, Cd accumulation in durum wheat (Triticum turgidum L. durum, cv. Balcali-2000), and micro (Zn, Fe, Cu, Mn) minerals differing in salt tolerance. The negative effects of Cd and NaCl stress on plant growth and Cd accumulation detected to alleviate Cd uptake on wheat growth increasing zinc application. The results revealed that Cd, NaCl and their combined stresses reduced shoots dry matter and Cd concentration in shoots increased compared to control pots. In increasing Cd and NaCl treatments, increasing Zn application significantly decreased the Cd concentration in shoot. In particularly, the decrease in Cd concentration was more noticeable with the improvement of Zn nutrition of plants at low doses of NaCl and Cd. The effect of increasing zinc treatments on reducing Cd accumulation decreased to slightly at high doses of Cd and NaCl. According to the results it can be suggested that Zn application to soils with low Cd content and medium salinity can be reduce Cd uptake by durum wheat.

Effect of Spraying with Humic Acid and Active Yeast Suspension on the Growth Indicators and Active Substances of Calendula officinalis L.

The purpose of this study was to examine the impact of spraying C. officinalis L. with Humic acid and active yeast suspension on growth indicators for both the vegetative and floral stages of development. Humic acid was sprayed on the plants in varying quantities (0, 2, or 4 g) in a factorial experiment with 9 treatments (two factors overlapped). and a suspension of live yeast at 3, 6, or 0 mg/L-1, and the treatment consisted of three sprays, with a 15-day gap between each application. Using a Factorial Experiment with three replicates and three plants per experimental unit, I compared means at the 5% probability level using the Revised Least Significant Differences (R.L.S.D.) test. The most significant findings, in her opinion, are as follows: Humic acid spraying at a dosage of 4 mg/L-1. While this concentration greatly slowed flowering, L-1 significantly increased plant height, number of lateral branches, percentage of dry matter of shoot, number of flowers, number of petals, flower diameter, flower stand length, and percentage of dry matter in flowers. The greatest concentration, 6 mg.L-1, was achieved through spraying with an active yeast suspension. Although this concentration greatly slowed flowering enhanced plant height, lateral branching, leaf count, flower count, petal count, flower diameter, and floral dry matter percentage. There was a statistically significant impact on all attributes measured by the binary interactions.

In vitro Regeneration of Multiple Shoots in Abelmoschus esculentus (L.) Moench (Okra) via Apical Shoot Meristem Culture

Introduction: To develop the efficient protocol for multiple shoot regeneration of A.esculentus by apical root culture method. Abelmoschus esculentus L., commonly known as okra, is a member of the Malvaceae family, which is widely consumed due to its high nutrient content and potential therapeutic properties. Okra contains various bioactive compounds that ex-hibit antibacterial properties and may be useful in treating type-2 diabetes, digestive diseases, and liver detoxification. To select the plant for the present and prepare the efficient protocol for the development of multiple shoot regeneration culture method. Methods: In this study, we developed an efficient protocol for multiple shoot regeneration of A. esculentus using the apical shoot culture method. Mature shoot apex explants of the germinated A. esculentus genotype CoBhH1 were cultured on Murashige and Skoog (MS) medium supple-mented with different concentrations of cytokinins (BAP and TDZ) and auxins (IAA and NAA) to determine the optimal conditions for shoot induction. Results: The highest number of multiple shoots (27.04 shoots) was obtained with 0.8 mg/L TDZ. Excised shoots were cultured on MS medium supplemented with GA3, which induced elongation of the shoots to a maximum of 8-10 cm. Regenerated plantlets were successfully transferred to soil, with a 100% survival rate and no differences in morphology or growth characteristics com-pared to control plants. Rooting was achieved with 1 mg/L IBA. Conclusion: This study provides an efficient protocol for multiple shoot regeneration of A. esculentus through apical shoot culture, which has potential applications in plant breeding and genetic engineering.

Nano-zinc and plant growth-promoting bacteria is a sustainable alternative for improving productivity and agronomic biofortification of common bean

Background and aimsNano-zinc (Zn) fertilizer is an easily adaptable and environmentally safe alternative option that can effectively improve growth, yield and biofortification of common bean. Plant growth-promoting bacteria (PGPBs) could promote plant growth and nutrients availability in sustainable manner. Therefore, this study aimed to investigate the influence of foliar nano-Zn application in association with seed co-inoculations of PGPBs on growth, yield, biofortification and Zn use efficiencies in common bean cultivation. Two field experiments were performed with seven co-inoculations of PGPBs and three foliar nano-Zn doses applied 50% at R5 and 50% at R8 stages of common bean to determine plant height, shoot dry matter, grain yield, Zn concentration and uptake in shoot and grains, Zn partitioning index, daily Zn intake and Zn use efficiencies for agronomic biofortification.ResultsThe combined foliar nano-Zn application and co-inoculation of R. tropici + B. subtilis enhance grain yield, leaf chlorophyll index, total protein content, grain Zn concentration and uptake, daily Zn intake, Zn use efficiency, applied Zn recovery and Zn utilization efficiency in common beans in 2019 and 2020 cropping seasons. Foliar nano-Zn application at a dose of 1.5 kg ha−1 increased plant height, shoot dry matter, shoot Zn uptake, Zn partitioning and agro-physiological efficiency under co-inoculation with R. tropici + B. subtilis in both cropping years.ConclusionsThe treatments with foliar nano-Zn application at a dose of 1.5 ha−1 and co-inoculation with R. tropici + B. subtilis improved performance, chlorophyll index, protein content, grain yield, and Zn efficiencies that can lead to better biofortification of common bean in tropical savannah. Therefore, it is recommended that applying nano-Zn via foliar along with co-inoculation of PGPBs could be the better option for productivity and biofortification of common bean.Graphical

Expression of CsSCL1 and Rooting Response in Chestnut Leaves Are Dependent on the Auxin Polar Transport and the Ontogenetic Origin of the Tissues.

The mechanisms underlying the de novo regeneration of adventitious roots are still poorly understood, particularly in trees. We developed a system for studying adventitious rooting (AR) at physiological and molecular levels using leaves excised from chestnut microshoots of the same genotype but with two distinct ontogenetic origins that differ in rooting competence. Leaves were treated with auxin and N-1-naphthyl-phthalamic acid (NPA), an inhibitor of auxin polar transport (PAT). The physiological effects were investigated by recording rooting rates and the number and quality of the roots. Molecular responses were examined by localizing and monitoring the changes in the expression of CsSCL1, an auxin-inducible gene in juvenile and mature shoots during AR. The rooting response of leaves was ontogenetic-stage dependent and similar to that of the donor microshoots. Initiation of root primordia and root development were inhibited by application of NPA, although its effect depended on the timing of application. CsSCL1 was upregulated by auxin only in rooting-competent leaves during the novo root organogenesis, and the expression was reduced by NPA. The inhibitory effect on gene expression was detected during the reprograming of rooting competent cells towards root initials in response to auxin, indicating that PAT-mediated upregulation of CsSCL1 is required in the initial steps of AR in chestnut leaves. The localized expression of CsSCL1 in the quiescent center (QC) also suggests a role for this gene in the maintenance of meristematic competence and root radial patterning.

Stigmaria: on the substrate before in the substrate

Stigmaria is the rooting organ of late Paleozoic arborescent lycopsids. Previous scientific considerations of the stigmarian habit have placed the entire rooting organ shallow beneath the substrate surface, despite the proximal main stigmarian axes radiating outwards orthogonally from the trunk in all known stump casts with attached Stigmaria. Here, we show definitively that stigmarian axes were subaerial proximally given both their preservation within and direct interaction with two independent volcanic ash layers. However, it remains uncertain whether these axes dove under the substrate surface distally and, if so, where along the axes this occurred. We test the aboveground or belowground nature of distal stigmarian axes with comparisons of sampling frequencies of vasculature from different regions of the arborescent lycopsid body plan as preserved in ‘coal ball’ permineralization fossils from the Pennsylvanian of Euramerica. The overabundance of root versus shoot material has previously been recognized as evidence of the enhanced preservation potential of organs growing within, rather than above, the substrate. We find that specifically the terminal stigmarian axis vasculature is overrepresented in the fossil record compared to trunk and proximal stigmarian axis vasculature, suggesting that the primary stigmarian axes and their secondary branches grew on the substrate before eventually going underground distally. Implications for arborescent lycopsid establishment are considered.

Bio-inputs promoting marandu grass growth: productivity, physiological response and nitrogen accumulation

Nutrient replenishment is one of the significant factors limiting the full development of extensive pasturelands. As a result, bio-inputs have been increasingly used under field conditions to improve plant growth in low-fertility soils. This study aimed to evaluate their effects on the productivity, physiological responses to and nitrogen (N) accumulation in marandu grass (Urochloa brizantha cv. marandu). The experiment was carried out using a randomized block design with four treatments and three replicates in a greenhouse under controlled conditions. In low-fertility soils, lower synthetic fertilizer inputs were simulated (40% N-P-K) (Control), and three bio-inputs were additionally applied (bio-inputs + 40% N-P-K): Azo (Azospirillum brasilense seed inoculation); HS+Herb (leaf application of humic substances combined with a cocktail consisting of Herbaspirillum species), and Coinoc (a combination of Azo and HS+Herb). We evaluated the plant biometrics (shoot and root dry matter, stem diameter and height) and physiological parameters (CO2 assimilation rate, internal CO2 concentration, transpiration, instantaneous carboxylation efficiency, and the maximum quantum yield of photosystem II), as well as the N accumulation 45 days after seedling emergence. Azo-treatment did not differ from the control in most of the variables studied. HS+Herb and Coinoc significantly (p ≤ 0.05) increased the dry matter of shoots (+237% and +255%, respectively) and roots (+106% and 83%, respectively) compared to the control. These treatments (HS+Herb and Coinoc) significantly (p ≤ 0.05) increased (almost double) the size and stem diameter, improved physiological parameters, and accumulated more N (up to 89%) compared to the control. Applying humic substance-based bio-inputs combined with the Herbaspirillum species cocktail was more efficient in stimulating the growth of marandu grass grown in soil of reduced fertility.

Germinating seedlings and mature shoots of Cuscuta campestris respond differently to light stimuli during parasitism but not during circumnutation.

Seedlings of the parasitic plant genus Cuscuta (dodder) locate hosts by circumnutation, coil around the host near soil level and form a haustorium, establishing a primary parasitism beneath the canopy. Mature shoots elongating from the parasitic region parasitize other hosts on the upper surfaces of their canopy. Although parasitism by dodder is stimulated by blue and far-red light, and inhibited by red light, the responses to light signals during the developmental stages are not comprehensively understood. Therefore, we compared the effects of different types of light on both circumnutation and parasitism by germinating seedlings and mature shoots of Cuscuta campestris. Seedlings established parasitism under blue and far-red light, but not under red light, as has been reported repeatedly. By contrast, mature shoots exhibited coiling around the host and haustoria formation even under a red light as well as under blue and far-red light. These findings indicate that C. campestris modified its response to red light during the transition from young seedlings to mature shoots, facilitating parasitism. Light quality did not affect the circumnutation of either seedlings or mature shoots, indicating that circumnutation and the coiling movement that leads to parasitism were regulated by different environmental signals.

Crescimento de porta-enxerto de maracujazeiro silvestre (Passiflora foetida L.) sob salinidades da água de irrigação

ABSTRACT Wild passion fruit species, due to the greater tolerance to environmental stresses, reveal potential as interspecific rootstocks. Passiflora foetida is a wild species potentially tolerant to salinity. Therefore, the objective with the study was to evaluate the effects of irrigation water salinity on the growth of wild passion fruit (P. foetida L.) rootstocks. The experiment was carried out in a protected environment. The treatments consisted of the electrical conductivity of the irrigation water (0.3; 1.0; 2.0; 3.0 and 4.0 dS m-1), distributed in randomized blocks. The assessments were performed at 7, 14, 21, 28 and 35 days after transplanting and consisted of: stem height and diameter, number of leaves, average leaf size, leaf area, and dry matter of shoots, roots and total. In younger rootstocks, the deleterious effects of salinity on height growth and leaf components were observed under lower electrical conductivities, with tolerance increasing with age. However, dry biomass accumulation was more severely restricted by salinity with increasing rootstock age. P. foetida rootstocks are salinity tolerant and can be irrigated with water of up to 4.0 dS m-1.

Drought effects on root and shoot traits and their decomposability

Abstract Drought can induce phenotypic plasticity in a range of plant root and shoot traits. These traits have been shown to explain differences in root and shoot litter decomposability between species. However, it is unknown how drought‐induced plasticity of root and shoot traits alters their decomposability. To investigate this issue across a range of species, we grew a grass Lolium perenne, a forb Plantago lanceolata and a legume Trifolium repens common to European temperate grasslands and subjected them to a 5‐week moderate drought treatment. We compared morphological and chemical root and shoot traits of the droughted plants to well‐watered controls. We then conducted a decomposition assay of the senesced root and shoot material over 16 weeks, with mass loss measurements at five timepoints. Drought had significant and sometimes strong effects on morphological and chemical root and shoot traits of all three species, sometimes similar to differences between species and generally in line with a shift to a more resource‐conservative strategy. Drought also increased the labile litter fraction in roots of Lolium perenne, which was associated with a substantial increase in non‐structural carbohydrates. Drought decreased the labile litter fraction in shoots of Plantago lanceolata, but this could not be explained by the traits we measured. Drought effects on litter decomposability were weaker than on plant traits. Our results suggest that plant trait‐mediated effects of drought on litter decomposability can either increase or decrease vegetation feedbacks to climate change. They also show that drought‐induced plasticity in root and shoot traits does not automatically translate into equivalent changes in litter decomposability. Read the free Plain Language Summary for this article on the Journal blog.

Grafting Causes Physiological Changes and Promotes Adventitious Root Formation in Rejuvenated Soft Shoots of Taxodium hybrid ‘Zhongshanshan’

Taxodium hybrid 'Zhongshanshan' has been widely used as a timber tree in river network areas and coastal regions and is mainly propagated by cuttings. However, when trees age, their capacity to form adventitious roots becomes weaker. We successfully enhanced the rooting ability of shoots in T. hybrid 'Zhongshanshan 302' by their rejuvenation based on grafting. We recorded temporal variation in endogenous auxin, abscisic acid (ABA), gibberellins (GAs), trans-zeatin-riboside (TZR), soluble sugar and H2O2 after root induction. Auxin, soluble sugars and H2O2 levels were higher in rejuvenated shoots than in mature shoots, whereas the opposite was true for ABA and GAs. Notably, indole-3-acetic acid (IAA) and GA3 presented higher contents with more obvious differences in T. hybrid 'Zhongshanshan 302' rejuvenated shoots vs. mature shoots compared with other kinds of auxin and GAs. The evident improvement in the rooting ability of rejuvenated shoots after grafting likely resulted from the differential regulation of plant hormones, carbohydrates and redox signaling. In addition to the physiological basis of improved rooting ability by grafting, this study provided a theoretical basis for the optimization of subsequent propagation techniques in T. hybrid 'Zhongshanshan' and potentially other Taxodium spp.