Improved Seedling Quality Research Articles

Nursery production, acclimatization, and orchard transplantation of Argania spinosa: Evaluating the impact of costs and plant age

The depletion of the argan area over time underscores the importance of enhancing the quality of argan seedlings to support regeneration. Key factors such as seedling age and nursery techniques including shade, substrate, and container play a crucial role in improving seedling quality and ensuring successful transplantation. Our study assessed the impact of seedling age, shading, substrate composition, and container volume on argan seedling production during the nursery phase and their influence in the transplantation phase. The findings revealed 40% shade covering in 12- and 18-month-old seedlings exhibited the most growth potential, while unshaded compartments were suitable for 6-month-old seedlings. Substrates S1, S3 and S6 respectively, resulted in the highest quality seedlings overall, with S1 being the most effective for 6-month-old seedlings, and S3 and S6 showing more impact for 12- and 18-month-old seedlings. Furthermore, the use of larger containers contributed to the production of high-quality seedlings. Field results showed lower mortality rates across different seedling ages (3.1% to 9.3%) and revealed no significant difference among the combinations, except for seedlings produced under 40% shade, where the S3C3 combination followed by S1C2 in the 6-month nursery production period demonstrated the highest relative growth rate in shoot length. The relative growth rate in diameter reported its highest value in the S1C2 combination of 18-month and 6-month-old seedlings. A cost benefit analysis was carried out, which revealed that the cost-effective combination was S1C2, followed by S3C3 for 6-month-old nursery age under the 40% compartment.

The Physiological Effect of Trichoderma viride on Melon Yield and Its Ability to Suppress Rhizoctonia solani

Melon damping off, which has a negative impact on melon quality and yield, can be safely and effectively managed with Trichoderma. Melon cultivar ‘Longtian No. 1’ was evaluated at both the adult and seedling stages in a pot experiment. The Rs and PD liquids were utilized as CK1 and CK2, respectively. Trichoderma viride Tv286 treatments T1B, T2B, T3B, and T4B were used based on Rs at concentrations of 104, 105, 106, and 107 CFU·g−1, respectively. The impact of several treatments on the antioxidant system and seedling quality of melon were assessed at 15, 25, and 35 days after sowing. We examined the effects of several treatments on melon quality, yield attributes, and physiological and biochemical markers during the adult stage at 10, 20, and 30 days after pollination. The effects of several treatments on melon damping off were also studied. Applying T. viride Tv286 at different rates effectively increased the activities of enzymes, including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), and polyphenol oxidase (PPO), in the leaves of melon seedlings, significantly reduced the malondialdehyde (MDA) content, and improved the root–shoot ratio and seedling strength index. In terms of its influence on promoting the effect of antioxidant system indicators, T3B performed well. Melon seedlings treated with T3B showed higher CAT, POD, SOD, APX, and PPO activities in their leaves 35 days after sowing compared to CK1 (189.74, 169.61, 175.36, 224.20, and 477.39%, respectively). The strong seedling index and root–shoot ratio showed improvements of 130.43 and 79.71%, respectively, and the MDA content dropped by 35.66% at 35 days after sowing compared to CK1. Varying the rates at which T. viride Tv286 was applied increased the nitrate reductase (NR) activity and nitrate nitrogen, proline (Pro), chlorophyll, soluble sugar, and soluble protein contents in mature melon leaves, increasing melon quality and yield. T3B is the most effective marketing campaign. Compared to CK1, mature T3B leaves had higher NR activity, nitrate nitrogen content, chlorophyll content, soluble sugar content, soluble protein content, and Pro content 30 days after melon pollination (100.40, 135.17, 68.59, 93.65, 158.13, and 238.67%, respectively). The soluble solids, soluble protein, soluble sugar, vitamin C contents, and yield of melon fruit increased by 50.07, 126.82, 60.62, 70.79, and 61.45%, respectively, at 30 days after melon pollination compared to CK1. Optimal management of melon damping off can be accomplished with the application of T. viride Tv286 at different concentrations, with T3B exhibiting the best effect. The control effects reached 90.48 and 72.99% at the seedling and adult stages, respectively. Overall, T. viride Tv286 improved seedling quality, damping off control efficacy, melon yield and quality, and the antioxidant system during the seedling stage and enhanced physiological and biochemical characteristics during the adult stage. This study indicates the potential of T. viride Tv286 conidia as a biological control agent because it can prevent plant disease, increase yield, and improve quality.

Currently Available Site Index Equations That Use On-Site Tree Measurements for Naturally Regenerated Longleaf Pine in Its Historical Range

The longleaf pine (Pinus palustris P. Mill.) forest type occupied a much greater area in the United States prior to the arrival of Europeans, estimated to be around 37.2 million hectares. This area has been greatly reduced, and these ecosystems now occupy only about 1.2 to 1.6 million hectares. However, there has been a great interest in the restoration of this forest type mainly due to concerns about the loss of ecosystem services associated with these forests; the improved seedling quality and yield potentials bolster those efforts. Beyond that, existing stands are actively managed through different types of practices, including thinnings, prescribed burns often to manipulate the vegetation of other species, and the various timings of clearcuts. Thus, managers need tools to estimate site quality and ultimately productivity. A commonly used measure of site quality is site index, or the height of some defined dominant portion of the stand at a standardized base or index age. The primary objectives are to summarize the 16 existing equations to estimate site index and dominant height in naturally regenerated longleaf pine stands and to examine and visually compare their predicted behavior across a range of site quality and age conditions. Important considerations when using site index of anamorphism and polymorphism as well as base-age invariance are reviewed. Biologically, polymorphism is often considered advantageous since for many species differences in site quality not only result in different asymptotic dominant heights, but also varying rates in their approach to the asymptote. Of the 16 equations examined, only nine of them were polymorphic in nature, but all equations were base-age invariant. There is not an individual equation that is clearly superior because, for instance, it is either anamorphic in nature, is polymorphic but developed based on anamorphic curves, fit using data obtained from temporary plots, or it is limited geographically. Given these limitations, others can use this publication as a reference to determine which equation they feel is best for their particular situation.

Seed Quality Enhancement Techniques in the Production of Elite Seedlings Suitable for Machine Transplanting in Rice

The goal of the current study was to study the effect of seed enhancement techniques for the production of elite seedlings suitable for machine transplanting in rice (ADT 45, CO 51) and an experiment was laid out in Factorial Completely Randomized Block Design (FCRD) in three replications in the Department of Seed Science and Technology, Tamil Nadu Agricultural University, Coimbatore during 2023. In order to overcome the major constraint in machine transplanting of rice ie., planting density (number of seedlings per hill), an improved seedling characteristics should be obtained. The treatment consists of T0 - Dry seeds, T1- Seed coating with Vithai Amirtham, T2 - Seed coating with Vithai Amirtham + Priming, T3 - Sprouted seeds, T4 - Seed coating with Vithai Amirtham+ Sprouted seeds, T5 - Seed coating with Vithai Amirtham+ Priming + Sprouted seeds. Among the different treatments, T5 sprouted seeds after coating with Vithai Amirtham (20 ml/kg) and hydro priming exhibits higher speed of germination, root length, shoot length, dry matter and vigour index than the control (dry seeds). From this study, it was concluded that seed coating with Vithai Amirtham and hydro priming has led to improved seedling quality characteristics, thereby the number of seedlings per hill during machine transplanting could be reduced and hence this would be a successful pre-sowing seed treatment to overcome the problem in machine transplanting of rice.

The tradeoff strategy between growth and survival in Quercus variabilis seedlings: determining the most limiting resource in the field drive shoot dieback

Abstract Shoot dieback is an important survival strategy in juvenile Quercus spp. However, it is unknown how nursery practices can influence the regulatory mechanisms of shoot dieback after planting. Furthermore, there is scarce information about the interactive effects between container depth and nursery fertilization on field seedling performance, and in combination with field weed control. Here, Quercus variabilis seedlings were cultivated the first year in with two container depths (25 cm, D40; 36 cm, D60) and with two nitrogen-loading levels (25, N25; 100 mg seedling−1, N100) in the nursery, and the following year, they were out-planted with/without weed elimination. We evaluated first year seedlings’ functional traits after nursery culture (plant and root morphology and nutritional status) and second year field performance (survival, shoot dieback, growth and nutrient increments), and their relationship. Independently of nursery culture, weed management was an irreplaceable practice to optimize seedling field performance. Seedlings grown in deep containers (D60) showed enhanced field growth and nutrient acquisition and reduced shoot dieback. Fertilization increased N and K loading (content and concentration) in the nursery, but showed no effect in the field. Low quality seedlings (low fertilization and normal container) maintained high survival rates at the expense of increasing shoot dieback rate. Thus, field survival did not differ among seedlings with differing nursery practices. Together, deep container and high N fertilization, increased plant nutritional reserves (content) and improved root system development, consequently, mitigating field shoot dieback. Under our experimental conditions, improved seedling quality by the use of deep container (D60) was sufficient to optimize field seedling performance without weed competition. However, both, deep container and nitrogen loading (D60-N100) were the best nursery practices to optimize seedling success without weed control in the field. Our study highlights that shoot dieback is a paramount trade-off strategy between growth and survival, which should be considered as an important indicator for further evaluating seedling field performance.

Application of Trichoderma viride and Pseudomonas fluorescens to Cabbage (Brassica oleracea L.) Improves Both Its Seedling Quality and Field Performance

Inoculating cabbage (Brassica oleracea L.) plants with bio-control agents and plant growth-promoting rhizobacteria (PGPR) can considerably improve seedling quality, growth, yield, and yield-related parameters over time. An experiment was conducted to evaluate the bio-fertilizer efficiency of a bio-control agent (Trichoderma viride) alone or in combination with PGPR (Pseudomonas fluorescens). Accordingly, various seedling quality and yield parameters were studied, and the results suggested that all the co-inoculation treatments displayed beneficial effects. Still, the combination of Trichoderma viride and Pseudomonas fluorescens showed the maximum increment in all the parameters considered, i.e., seedling emergence, seedling height, stem diameter, leaf area, root length, seedling vigour index, seedling fresh weight, seedling dry weight, total chlorophyll content, plant height at 30 DAT, plant height at 60 DAT, leaf numbers, leaf area index, root length, root dry weight, number of non-wrapping leaves, number of wrapping leaves, head weight, head diameter, and head yield. The findings appear to offer a viable bio-control technique for crop protection as bio-fertilizers bundled in a single formulation.

Trichoderma harzianum Suşlarının Domates Fide Kalitesine Etkileri

This study was conducted to determine the effects of Trichoderma harzianum on seedling growth and quality as two consecutive experiments during the spring months of 2018. In the first experiment, four different T. harzianum strains and a commercial preparate were used by adding into seed sowing substrate and compared with control group which had no treatment. The most promising strain (strain2), was used with and without foliar fertilizer (20:20:20) and foliar fertilizer itself was considered as control. Emergence period and rate were determined to observe the effects of treatments of germination of seeds. Regarding the seedling growth and quality, seedling length, root length, hypocotyl diameter, leaf thickness, fresh and dry weights of root and shoots, dry matter content, color, chlorophyll index, leaf macro and micro plant nutrient contents and seedling quality index were determined at the planting stage. Data obtained from the first experiment showed that the effects of T. harzianum strains on seedling morphology, physiology and nutrient content were different. Among the tested strains, strain2 showed better performance on seedling length, root and shoot dry matter contents, total fresh weight, chlorophyll, a color value and P, Ca, Mn, Cu and Zn contents of leaves and improved seedling quality. The second experiment result showed that the foliar fertilizer application increased the efficiency of T. harzianum strain2. T. harzianum strain2 without foliar fertilizer remained below the control treament in all measured parameters. When all the data were evaluated together, it was concluded that T. harzianum could be used to increase seedling quality due to its positive effects on seedling biomass, plant nutrition uptake and quality index. Moreover, it can be used in organic seedling production as alternative biostimulant.

Extraction of fulvic acid by citric acid–ethanol method and its biochemical activity

AbstractBACKGROUNDWith the widespread application of fulvic acid (FA) in agriculture, improving the industrial yield of FA has become an urgent priority. Therefore, it is particularly important to explore efficient and clean process conditions for the factory production of FA from low‐rank coal, as undertaken in this study. Additionally, an in‐depth study of the biological activity of FA was performed to provide a theoretical reference for its practical application.RESULTSResults showed that, when the reaction temperature was 70 °C, the ratio of citric acid to coal was 0.03:1, the ratio of liquid to solid was 10:1 and the concentration of ethanol was 15%, the average yield of FA was about 80‰. Seed soaking with FA promoted seed germination and improved seedling quality. As the concentration of FA for seed soaking increased, the germination potential, amount of reduced tetrazole and root length were reduced, but the relative electrical conductivity and chlorophyll content were increased.CONCLUSIONCoal‐based FA was effectively extracted by the citric acid–ethanol method and the yield of FA was relatively high under the optimum conditions. The treatment of cucumber seeds and seedlings with different concentrations of FA effectively promoted seed germination and seedling growth. © 2021 Society of Chemical Industry (SCI).

Scarification of Seeds of Capsicum chinense Jacq. With Phytohormones and Physicochemical Treatments to Improve Seedling Quality

Scarification of Seeds of Capsicum chinense Jacq. With Phytohormones and Physicochemical Treatments to Improve Seedling Quality

Comparing the effects of four propagation methods on hybrid chestnut seedling quality

Extensive resources have been used to breed hybrid chestnuts for reintroduction into the historical range of the American chestnut (Castanea dentata). Improving seedling quality is an efficacious method to improving restoration outcomes and nursery propagation methods can be selected to improve seedling quality, increasing the likelihood of survival. Four production methods (bed grown, air prune beds, container grown, and a multi-container method) and three media types (field soil, peat-perlite-vermiculite mix, and pine bark-rice hulls-sand mix) were compared across four measures of seedling quality (height, root collar diameter, root volume, and number of first order lateral roots) to examine their effects on seedling quality. Additional analyzes of survival and cost per seedling were conducted as well. Air prune beds performed comparably in both seedling quality and cost to standard bed grown and container grown seedlings with potential advantages over these two methods. Multi-container method seedlings underperformed compared to bed grown and container grown seedlings. A decision tree was produced to assist nurseries in selecting a propagation method most appropriate to their nursery, intended restoration site, and constraints.

The High Cost of the Low-Cost Polybag System: A Review of Nursery Seedling Production Systems

An important strategy for meeting global landscape restoration goals is nursery production of high-quality seedlings. Growing seedlings with attributes that promote post-planting survival and growth can be dramatically influenced by the nursery container system. In many countries, nurseries produce seedlings in polybags filled with excavated soil. These seedlings often develop deformed roots with limited fibrosity which can lead to poor survival and growth after outplanting. Polybags are initially inexpensive but using these single-use plastic containers accrues expenses that are often untracked. Comparisons among nursery production systems must account for factors such as container longevity, labor efficiency, and seedling field performance. A more holistic approach to account for environmental, economic, social, logistic, and cultural elements in the cost–benefit equation that influences nursery production systems is needed. Converting to a modern container system requires concomitant adjustments in nursery scheduling and culturing matched to the new stock type. Doing so provides an opportunity to align nursery production techniques and resulting seedling attributes with anticipated field conditions. This article describes and discusses the advantages and disadvantages of nursery production systems and provides recommendations and case studies to aid nurseries in improving seedling quality toward meeting restoration goals in a cost-effective and timely manner.

Earthworm (Eisenia fetida) Mucus Inspired Bionic Fertilizer to Stimulate Maize (Zea mays L.) Growth

Background: Increasing population and food consumption are placing unprecedented demands on crop production. Maize is one of the most important food crops in the world, the improvement of its yield primarily depends on the application of chemical fertilizer. Methods: Earthworm activity is an essential factor in promoting soil fertility and stimulating plant growth. Inspired by amino acids composition of earthworm (Eisenia fetida) epidermal mucus, the liquid fertilizer was developed and prepared by utilizing a bionic approach. The influence of earthworm epidermal mucus (mucus), the mucus-mimicked mixture of amino acids (bionic fertilizer) and urea fertilizer (urea) on maize emergence and growth were studied and compared with the control group (distilled water). Experimental cultivation tests were conducted. The aforementioned three types of liquid fertilizer effects on maize seed vigor index, seedling emergence rate and plant quality were quantitatively evaluated. Results: Based on the conducted research, it was found that the beneficial effects of different fertilizers for maize emergence rate were ranked as follows: mucus > bionic fertilizer > urea. The low concentration treatments were beneficial to the maize emergence, while the high concentration treatments were helpful to the maize growth and root development. Besides, the lower concentration of mucus was the most effective fertilizer treatment for improving seedling quality. In addition, the test results of three types of liquid fertilizer effects on maize growth indicated that the higher concentration treatments provided more nitrogen nutrition than lower concentration treatments. Furthermore, the maize stem height and diameter were significantly promoted (p < 0.05) by the three types of liquid fertilizer. The beneficial influences of liquid fertilizer treatments for plant height, stem diameter, relative chlorophyll content and photosynthetic characteristic of leaves were ranked as follows: bionic fertilizer > urea > mucus. Conclusions: Bionic fertilizer demonstrated significant beneficial fertilizing effects (p < 0.05), which increased soil nutrients, improved maize physiological parameters, promote its growth and improved dry matter accumulation. The tested results verified the effectiveness of bionic fertilizer on stimulating maize growth.

Root Zone Management for Improving Seedling Quality of Organically Produced Horticultural Crops

Currently, vegetable production systems have been changed to improve yield and quality, leading to an improvement in sustainability. In horticultural cultivation, one of the most important sectors is the seedling production in nurseries. In the past, horticultural seedlings were produced directly by farmers. Nowadays, industrialized nurseries provide seedlings characterized by a uniform growth and an early and contemporaneous development. In addition, consumer concern about the impact of food production on the environment is driving an increased demand for organic vegetables with a consequent increase of agricultural land cultivated by organic methods. Hence, there is a need to produce high-quality seedlings suitable to be cultivated in the organic farming system. Root zone management, for improving seedling quality of organic horticultural crops, remains largely unexploited, such that this review highlights some of the current research and future development priorities, providing useful information to nursery growers. In particular, we reviewed all the scientific and modern knowledge on the production of organic, healthy and vigorous seedlings including the use of: (1) compost and compost tea; (2) agroindustrial byproducts; (3) microbial and non-microbial plant biostimulants; (4) beneficial microorganisms.

Optimization of maturation process for somatic embryo production and cryopreservation of embryogenic tissue in Pinus koraiensis

Korean pine broadleaf mixed forests are important for maintaining biodiversity in Northeast China. Excessive harvesting of the Korean pine tree has led to it being listed as an endangered species in China. Somatic embryogenesis technology has the potential to accelerate breeding by improving seedling quality to meet future wood harvesting needs. In addition, rare and valuable germplasm resources can be maintained through the use of cryopreservation. Here, we described the utilization of somatic embryogenesis in Korean pine, with a focus on maturation and cryopreservation. Embryogenic tissues (ETs) were induced from immature seeds collected from open-pollinated sources of Korean pine (28 families). Highest induction percentage of ET reached 22%. The proliferation ability of ET in different cell lines differed. Increasing ABA(up to 80 µM L− 1), gellan gum (up to 12 g L− 1) and sucrose (0.2 m L− 1) concentrations in maturation medium improved the yield of cotyledonary somatic embryo (SE). Maximum yield of cotyledonary SEs (160 SEs g− 1 fresh mass) was obtained following ET dispersion on filter paper discs at low density (50 mg fresh mass). Both the germination percentage of SEs and survival percentage of regenerated plants were about 50%. Moreover, ET began to lose their potential for somatic embryogenesis after 6 months of subculture. ET cultures were cryopreserved, and culture recovery (133 SEs g− 1 fresh mass) was demonstrated after thawing. In this paper we report a significantly improved procedure for generating Korean pine SEs, leading to a high yield of cotyledonary SEs. A cryopreservation protocol for the ET of Korean pine was also established. The present work reports a significantly improved procedure for generating somatic embryos and cryopreservation of embryogenic tissue in Korean pine.

Application of Cytokinin and Mycorrhiza to Increase Production and Quality of Pineapple Seedlings from Crown Leaf Bud Cuttings

The pineapple vegetative propagation method using crown leaf bud cuttings has potential to produce seedlings of greater uniformity and in larger quantities than other methods. This study, aimed to explore the potential eff ects of concentration and frequency of Benzylaminopurine (BAP) application for increasing the production and quality of pineapple seedlings from crown leaf bud cutting propagation. The experiment used a randomized complete block design (RCBD) with two factors. The fi rst factor was the concentration of BAP (0, 200, 400, 600, 800 ppm) and the second factor was the frequency of BAP application (1, 2, 3 times). Furthermore, this study investigated the eff ects of applying mycorrhizae to accelerate seedling growth and improve seedling quality during production from crown leaf bud cutting propagation. The experiment used a RCBD with one factor (dose of mycorrhiza: 0, 50, 100, 150, 200 spores). The results indicated that the eff ects of concentration and frequency of BAP application and their interaction increased seed production as determined by sprout cuttings at 5 weeks after planting by applying 600 ppm 2 times. Generally, with increasing concentration and frequency of BAP application, leaf chlorophyll content was reduced. However, the application mycorrhiza positively infl uenced the production of seedlings from pineapple crown bud cuttings and improved seedling quality as measured by root dry weight, chlorophyll content, root infection, and phosphatase enzyme activity.

Biomass and Nutrients Variation of Chinese Fir Rooted Cuttings under Conventional and Exponential Fertilization Regimes of Nitrogen

Exponential fertilization has been regarded as an important technique for improving seedling quality at the initial plant-growth stage. In our study, containerized one-year-old Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) rooted cuttings were reared at four nitrogen (N) fertilizer levels (0, 0.5, 1.0, 2.0 g cutting−1 season−1) under two topdressing methods (conventional and exponential) for a 210-day greenhouse rotation to evaluate growth and nutrient loading capacity of seedlings. N fertilizer was applied 20 times at an interval of 10 days during the study period. The results indicated that the schedule and rate of fertilization significantly affected the height, ground diameter, and biomass of Chinese fir rooted cuttings. The nitrogen concentration of different plant organs followed the order of leaves > root > stem. Compared to the CK, the N concentrations in root, stem, and leaves increased by 39.6%, 16.6%, and 41.1% in the conventional fertilizer treatment, and by 22.6% to 81.4%, 27.3% to 152.6%, and 73.6% to 135.5% in exponential fertilization treatments, respectively. The N concentrations of root, stem, and leaves of Chinese fir rooted cuttings under EF2 (1.0 N g cutting−1) were significantly higher than that of conventional fertilization (p < 0.05). However, there was no significant difference of phosphorus and potassium concentrations among different plant organs. Steady-state nutrition and superior growth performance were achieved by rooted cuttings fertilized exponentially at the rate of 1.0 g cutting−1 yielding (EF2).

Potential use of biochar in raising machine-transplanted rice seedlings

Improving seedling quality is important for obtaining high yield in machinetransplanted rice production. In recent years, it has been of interest to use biochar in growing media. However, limited information is available on the potential use of biochar in raising machine-transplanted rice seedlings. This study was conducted to provide such information through determining the effects of biochar addition on machine-transplanted rice seedling traits in a tray experiment. Root length, surface area, volume, and biomass of machine-transplanted rice seedlings grown in nursery soil amended with biochar at a volume-by-volume ratio of 3: 1 (NMSC) were 21–53% greater than those in soil only (NMS). Leaf area, height, basal stem diameter and shoot biomass were 6–21% greater in machinetransplanted rice seedlings grown in NMSC than in NMS. Water culture test showed that number of newly formed roots was 42% more in machine-transplanted rice seedlings grown in NMSC than in NMS. Length of the longest new root was 13% longer in machinetransplanted rice seedlings grown in NMSC than in NMS. These results suggest that biochar presents a potential use in raising machine-transplanted rice seedlings.

Investigation of Exogenous Benzyladenine on Growth, Biochemical Composition, Photosynthesis and Antioxidant Activity of Indian Sandalwood (Santalum album L.) Seedlings

Cytokinins play essential roles in many aspects of plant growth and development. To study the effects of benzyladenine (BA) on growth and metabolism of Indian sandalwood (Santalum album L.) seedlings, the influences of BA concentrations of 0, 1, 10 and 100 mg L−1 on growth, biochemical components (proteins, sugars, chlorophylls and carotenoids) and gas exchange parameters as well as oxidative status were investigated through a pot cultivation experiment. The results showed that BA acted in a biphasic manner. Treatment with BA at 1 mg L−1 promoted stem growth, crown width and dry biomass accumulation, improved seedling quality, enhanced the net photosynthetic rate and instantaneous water use efficiency and stimulated photosynthetic pigment (chlorophyll a, chlorophyll b and carotenoid) accumulation greatly. Moreover, the contents of soluble proteins and sugars were also increased, but the height growth was inhibited considerably. Meanwhile, the activities of most antioxidant enzymes (catalase, peroxidase and superoxide dismutase) were also strengthened significantly, and therefore lipid peroxidation was inhibited greatly. In contrast, no significant improvement was observed on ground diameter, crown width, biomass, quality index, chlorophyll a content, chlorophyll b content or net photosynthetic rate when treated with 10 and 100 mg L−1 BA, but the oxidative status was aggravated, as a result of which lipid peroxidation was intensified. The data proved that BA was one of the most active plant growth regulators on growth and metabolism of S. album seedlings, and suggested that leaf application of 1 mg L−1 BA was the most suitable concentration for enhancing seedling quality during the nursery period.

Soaking seeds with paclobutrazol enhances winter survival and yield of rapeseed in a rice-rapeseed relay cropping system

Rice-rapeseed relay cropping is an effective way to use winter fallow fields and increaseland use efficiency. However, the overlapping period of 10–15 days for rice-rapeseedcultivation results in reduced winter survival and less yields. Therefore, in this study, weinvestigated if the treatment of oil rape seeds with paclobutrazol (PAC) improves its winterhardiness and yields by altering its crop morphology. First, a pot experiment was conducted todetermine the appropriate PAC concentration to soak seeds upon seedling growth and thegermination rate. Another pot trial was performed to check the responses of different rapeseedcultivars to the proposed treatment. Rapeseed was cultivated in no-tillage rice fields at anexperimental site in Wuhan from 2009 to 2011. In the absence of PAC treatment, rapeseed sownin pots and rice fields showed excessive elongation of the crown, which resulted in low yieldsand yield-related traits at maturity. Soaking seeds in PAC improved seedling growth, seedlingsurvival and crown diameter, but decreased the crown length during winter. The most effectiveconcentration of PAC was 4 mg/L and higher concentrations significantly reduced seedgermination rates. Our results demonstrated that rapeseed sown in rice fields after the seeds hadbeen soaked with PAC improved seedling quality at the wintering stage and yield at maturity.

Restoration Silviculture: An Ecophysiological Perspective - Lessons learned across 40 years

Involvement in forest restoration programs across North America for the past 40 years, dealing with nursery cultural practices, operational seedling quality programs and defining seedling performance on restoration sites has given me a unique perspective, which I have used to examine programs from both a research and operational perspective. Certain biological patterns and themes continually appeared across these programs and this paper discusses five of the most common themes.Learning To Think Like a Tree – It is important for practitioners to develop an understanding of the ecophysiological performance of tree species in a nursery or forest restoration program in order to understand how seedlings grow. This understanding leads to sound biologically based cultural decisions to improve seedling performance.Stress and the Cyclical Nature of Stress Resistance – Seedlings are exposed to stress when environmental conditions limit their performance. Plants develop physiological resistance attributes to mitigate stress and these attributes change throughout the seasonal cycle. Practitioners have developed hardening cultural practices that enhance seedling stress resistance, thereby improving seedling quality and site restoration success.Seedling Quality: Product versus Process – Seedling quality is an important component of successful restoration. Typically seedling quality is examined from a product perspective, thus defining functional integrity, operational grading or sometimes performance potential. An alternative approach monitors the process, with product quality the final output.Planting Stress and Seedling Establishment – Planting stress is prevalent in forest restoration. The act of planting can result in a seedling that does not have proper connections for water movement through the soil-plant-atmosphere continuum (SPAC). Seedling water stress, reduced growth performance and potentially death can occur if this SPAC connection is not restored.Seedling Death: Sometimes Simple and Sometimes Complicated – Seedling death can occur in restoration programs as a result of environmental extremes or incorrect management practices. Some problems can be easy to diagnose and correct practices can be implemented to rectify the problem. Other times, issues are complicated and it can be a challenge to define the potential factors causing seedling death.