Pertumbuhan dan Produksi Pucuk Kenikir pada Beberapa Komposisi Media Tanam dan Interval Pemanenan (The Growth and Shoot Production of Cosmos caudatus with Various Plant Media Composition and Harvesting Interval)

<p>Kenikir dapat dimanfaatkan sebagai sayuran dengan cara mengonsumsi pucuknya. Kenikir banyak dijumpai sebagai tumbuhan liar sehingga diperlukan upaya untuk meningkatkan produksi pucuk kenikir. Produksi pucuk kenikir dapat dioptimalkan dengan melakukan perbaikan teknik budidaya, salah satunya pengaturan komposisi media tanam dan interval panen pucuk. Tujuan dari penelitian ini adalah untuk menganalisis pengaruh komposisi media tanam dan interval pemanenan terhadap pertumbuhan dan produksi pucuk kenikir. Penelitian dilaksanakan pada bulan Februari sampai dengan Mei 2019 di Kebun Percobaan Fakultas Pertanian UGJ, Cirebon. Percobaan dilakukan dalam dua tahap, yaitu pengaruh komposisi media tanam terhadap pertumbuhan dan produksi pucuk kenikir pada panen pertama serta pengaruh interaksi antara komposisi media tanam dan interval pemanenan terhadap produksi pucuk pada panen kedua. Rancangan percobaan pada percobaan pertama menggunakan Rancangan Acak Kelompok (RAK) satu faktor, yaitu komposisi media tanam dengan sembilan ulangan dan rancangan percobaan pada percobaan kedua menggunakan RAK faktorial dua faktor. Faktor pertama adalah komposisi media tanam dan faktor kedua adalah interval pemanenan dan diulang sebanyak tiga kali. Komposisi media tanam terdiri atas tanah, tanah : pukan (2:1), dan tanah : pukan (1:1). Interval pemanenan yang dicobakan terdiri atas tiga taraf, yaitu 10, 15, dan 20 hari. Hasil penelitian menunjukkan bahwa media tanam tanah : pukan (1:1) meningkatkan pertumbuhan dan produksi pucuk kenikir baik pada saat panen pertama maupun panen kedua. Interval pemanenan 20 hari menurunkan produksi pucuk total disebabkan interval pemanenan yang terlalu lama menyebabkan banyaknya pucuk kenikir yang berbunga sehingga menjadi tidak layak untuk dipanen.</p><p><strong>Keywords</strong></p><p>Interval pemanenan; Kenikir (Cosmos caudatus); Media tanam; Pertumbuhan; Produksi pucuk</p><p><strong>Abstract</strong></p><p>Cosmos caudatus can be used as vegetable by its shoots. Cosmos are found as wild plant so that efforts are needed to increase shoot production. Shoot production can be optimized by media composition and harvesting interval. This research objective was to investigate planting media composition and harvesting interval effect on growth and shoot production of cosmos. The research was carried out for three months at Cirebon. The experiment was carried out in two stages: (1) the effect of media composition on growth and shoot at the first harvest and (2) the effect of interaction between media composition and shoot harvesting interval at the second harvest. The experimental design for first experiment used Randomized Block Design (RBD), namely the composition of media of soil, 2:1 soil-manure and 1:1 soil-manure with nine replications. Meanwhile, we used two factor factorial RBD for second experiment. The first factor was the media composition and the second factor was three harvest interval with three replications. The result showed that planting media of soil and manure (1:1) increased the growth and shoot both in the first and second harvesting. The harvesting interval of 20 days decrease the total shoot because many branches to flower so they cannot be harvested.</p>

Cryopreservation and Micropropagation Methods for Conservation of Genetic Resources of Ulmus laevis and Ulmus glabra

Elms are threatened by Dutch elm disease, and conservation methods are needed to protect their genetic diversity. Cryopreservation of dormant buds allows large numbers of genotypes to be conserved with small space requirements and minimal upkeep. Cryopreservation through slow controlled cooling was tested for both elm species native to Finland, Ulmus glabra and Ulmus laevis. Regeneration of the thawed buds by micropropagation was studied on different basal media and using different growth regulators. Multiple surface sterilisation methods were tried out for bud explants. The multiplication of U. glabra was investigated with Driver and Kuniyuki walnut medium with either 0.5 mg/L meta-topolin or 0.5 mg/L 6-benzylaminopurine. Rooting with short indole-6-butyric acid induction in liquid medium and direct transplantation of the shoots to peat ex vitro after induction were tested. For initiation, either Murashige and Skoog or Driver and Kuniyuki walnut medium with 0.02 mg/L gibberellic acid 4 + 7 and 0.5 mg/L 6-benzylaminopurine were found to best promote shoot formation. Surface sterilisation remains the most challenging step. No significant differences were found between the multiplication media in either shoot production or rooting success. Rooting by direct transplanting was achieved in both species, but further development is required before application on a larger scale. With further improvements to sterilisation success especially in U. glabra, the method can be applied to the conservation of genetic resources of both U. laevis and U. glabra, and knowledge of regeneration success can be used to design the cryoconservation plan and optimise the sampling.

Effects of one dark septate endophytic fungal and two Helotiales strains on the growth of Salix planifolia cuttings on iron ore waste rock

Plants maintain beneficial mutualistic relationships with the mycobiont communities found in their rhizosphere, leading to an increase in plant productivity and health. In nutrient-depleted substrates like mine tailings, mycobiont inoculation is often recommended to help restore a successful plant cover. Our 15-week greenhouse experiment aimed to assess the individual effects of a dark septate endophyte (Phialocephala fortinii #4; KX611529) and two Helotiales strains (Rhizoscyphus ericae #22; EU221877 and Meliniomyces sp #1; KT275679) on the growth of Salix planifolia cuttings on sterilized and unsterilized waste rock. Rhizoscyphus ericae increased cuttings shoot biomass on sterilized waste rock while Meliniomyces sp had a positive effect for cuttings grown on unsterilized waste rock. However, P. fortinii strain had no effect on the survival rate, shoot production, and biomass production of S. planifolia cuttings. This study demonstrates that controlled inoculation with ecologically well-adapted mycobionts could promote plant establishment and productivity on abandoned waste rock and be an efficient and integrated biotechnological approach for ecological restoration of canadian mining boreal ecosystems.

Root Tip Growth and the Presence of Leaves Affect Epicormic and Lignotuberous Shoot Development and Survival of Stressed Eucalyptus obliqua L’Herit. Seedlings

The shoots produced from axillary, epicormic, and lignotuberous buds are significant parts of stress recovery responses in many tree species. The production of either epicormic or lignotuberous shoots does not guarantee survival of a tree, as the mortality of shoots is high. This research investigated the relationship between root tip growth and shoot production and survival after stress and its implications for urban tree managers. Seedlings of Eucalyptus obliqua L’Herit. were stressed by decapitation or different levels of heat stress at temperatures ranging from 40 °C to 100 °C for 2 to 128 minutes, as well as combinations of the two stresses. While the temperatures are not as high as those experienced in a forest fire, the stresses imposed can inform plant responses to stress such as fire. Lower temperatures and shorter durations were often sublethal, and decapitation, to the same extent as heat killing of plant tissues, elicited similar levels of epicormic and lignotuberous shoot growth. The root systems of the seedlings were inspected to determine whether the root tips were healthy, and selected root tips were monitored to determine if and when they had resumed growth. Survival rates of epicormic and lignotuberous shoots were enhanced by the presence of healthy leaves. The recommencement of growth after stress by the development of epicormic or lignotuberous shoots was preceded by root tip growth, which emphasises the importance of a healthy root system. Managing for the best soil conditions possible during and immediately after stress may be a key to successful shoot production and tree recovery.

Induction of Somatic Embryogenesis and Organogenesis in Zimbabwean Sweet Potato (cv Brondal)

Somatic embryogenesis (SE) and organogenesis are crucial in the development of disease free plants and genetic engineering. An investigation was conducted on the ability of treatments containing a combination of 2,4-D and Kinetin to induce either SE or organogenesis from cultured sweet potato cv Brondal leaves. Ten treatments were evaluated and each treatment had an exclusive combination of 2,4-D (at 0.05, 0.1, 0.2, 0.5 or 1 mg/L) to kinetin (at either 0.1 or 0.5 mg/L). Callus initiation occurred earlier in treatments containing higher hormonal concentrations. The 2,4-D to Kinetin ratio had a highly significant ( p = 0.001 ) effect on callus growth and proliferation. Increasing 2,4-D to Kinetin ratio promoted profuse explant callusing while increasing Kinetin to 2,4-D ratio suppressed callusing but encouraged organogenesis, in particular shoot production (treatment containing 0.05 mg/L 2,4-D and 0.5 mg/L Kinetin). Embryogenic calli were formed seven weeks after leaf culture in the treatment containing 0.5 mg/L 2,4-D and 0.1 mg/L Kinetin. The embryogenic calli that developed from this treatment emerged from previously nonembryogenic calli. Plantlets produced via the SE pathway proved to be weak and unviable and died within four weeks of germination. In contrast, plantlets produced under organogenesis were strong, grew vigorously, and could be subcultured several times. This disparity may be accounted for by the fact that the cv Brondal embryos that developed under SE were not exposed to an embryo maturation staged before plantlet germination was initiated. The maturation stage would have assisted embryos to reach physiological maturity and a desired level of desiccation, both being critical elements in embryo to plantlet conversion. In this experiment, cv Brondal regeneration from leaf explants was successfully achieved via organogenesis using 0.05 mg/L 2,4-D and 0.5 mg/L Kinetin, and tentative steps towards development of SE based regeneration protocol were established using 0.5 mg/L 2,4-D and 0.1 mg/L Kinetin.

Cytokinin-like effects of chitosan on in vitro culture of Origanum vulgare L.

Oregano (Origanum vulgare L.) is a multi-purpose plant species with medicinal, culinary, and ornamental merit, which needs to be produced at an industrial scale. In the present research, effects of N-acetylated (10%) chitosan (CHT), 6-benzylaminopurine (BAP), and kinetin (KIN) on in vitro seed germination and shoot development in O. vulgare were studied in a concentration-dependent manner. The seed germination and shoot induction rates were mostly enhanced after CHT and KIN treatments, while BAP treatments reduced the rates. The chitosan treatment significantly triggered leaf production and shoot elongation better than the cytokinin treatments. The maximum shoot length (4.38±0.17 cm) and leaf number (17.71±0.69 leaves per shoot) were reached after chitosan treatment at 0.75 mg L-1, while shoot numbers were reduced after all chitosan and cytokinin treatments at low levels. However, shoot production was significantly enhanced in the presence of 2.0 and 4.0 mg L-1 KIN in the medium. Adventitious rooting without using auxins also occurred during the incubation period. The cluster analysis showed that the effects of 0.50 and 0.75 mg L-1 CHT treatments were better than BAP and KIN in stimulating shoot growth and leaf development in oregano. This study suggested that CHT might be used as a substitute for synthetic cytokinins to produce longer shoots and a high number of leaves in oregano propagation. Therefore, CHT might play a cytokinin-like role in plant tissue cultures. However, the effects of chitosan treatment might differ among species and according to its chemical structure

Ecological and hydrological considerations for climber weed control in freshwater forested wetland restoration project on the Gulf of Mexico

Two herbaceous Ipomoea climbers grow over trees planted to restore a freshwater forested wetland in the Gulf of Mexico, causing high tree mortality and limiting restoration success. To better control these species, we evaluated their potential for biomass accumulation and regeneration following removal. We simulated the tree-climber relationship in a field experiment by varying light conditions and trellis availability, and by cutting aerial biomass. We also considered the spatial variability of the wetland’s flood level. Ipomoea tiliacea accumulated more biomass at low flood levels, while Ipomoea indica accumulated more biomass at higher flood levels. Despite this, I. tiliacea accumulated more biomass over the entire flood level gradient and the highest flood levels seem to prevent regeneration in both species. There was no vine seed germination, so for both species, regeneration relied on shoot production. I. tiliacea increased its growth more than I. indica when trellises were available, even under shade. It means that that restoration conditions favor I. tiliacea, which makes its management specially challenging. We recommend characterizing hydrology of the site under restoration to design more effective Ipomoea control strategies. Future efforts to restore this forested freshwater wetland should select areas with the highest flood levels, where I. tiliacea growth is limited, ensuring that the trees to be planted can withstand the flood levels. Removal should be avoided during the dry season, when low flood levels favor regeneration in both species.

Case study of a rhizosphere microbiome assay on a bamboo rhizome with excessive shoots

Young Moso bamboo shoots are a very popular seasonal food. Bamboo is an important source of income for farmers and the value for cultivation has recently been estimated to $30,000 per hectare. A rare and valuable phenomenon has recently appeared where dozens of adjacent buds within a single Moso bamboo rhizome have grown into shoots. Due to its rarity, this phenomenon, which is of practical importance for the production of edible shoots, has not been scientifically studied. We report the occurrence of a rhizome with 18 shoots, of which the microbiome were analyzed, using rhizomes having one or no shoots as controls. The community of prokaryotes, but not fungi, correlated with the shoot numbers. Burkholderia was the most abundant genus, which negatively correlated with rhizome shoot number, while Clostridia and Ktedonobacteria positively correlated with many shoots. Two Burkholderia strains were isolated and their plant-growth promoting activity was tested. The isolated Burkholderia strains attenuated the growth of bamboo seedlings. Analysis of collected events of enhanced shoot production in China showed no evidence that enhanced shoot development was heritable. Overall, our data provides a firsthand study on excessive shoot development of bamboo.

Optimizing micropropagation conditions for a recalcitrant ninebark (Physocarpus opulifolius L. maxim.) cultivar

Ninebark is a very popular ornamental shrub. Micropropagation is an efficient method for mass production of uniform plant material. This study was designed to develop and optimize conditions at all phases of ninebark micropropagation. For the multiplication stage, the Murashige and Skoog (MS) medium at full concentration and pH 5.8 was chosen as the basal medium. Sorbitol proved a more effective carbohydrate source than fructose, with no adverse effects on shoot vitrification or the medium itself. The best shoot production, both in number and length, was on the medium enriched with 2 and 3 mg·L−1 zeatin. High numbers of shoots were also obtained in treatments with 1 mg·L−1 6-benzyladenine (BA) or 2 mg·L−1 meta-Topolin (mT) in the basal medium. BA was the most cost-effective cytokinin. There was a positive effect of the gibberellic acid on proliferation: the highest shoot number per explant was produced in the presence of 1 mg·L−1 GA3. No effect of the culture age (up to 20 subcultures) on the percentage of regenerating explants was evident, and the highest numbers of shoots were obtained between passages 10 and 17. For rooting, the MS medium at half strength was used. The best rooting was at 1 mg·L−1 IBA. Spraying the in vitro rooted cuttings with abscisic acid (ABA) favored plant acclimation to the ex vitro conditions. Exvitro rooting, including the treatments with IBA and ABA, shortened the production time by approximately one third.