Echeveria is a genus belonging to the Crassulaceae family that comprises approximately 170 species. It is a representative plant known as a succulent with economic potential in the floriculture industry. Echeveria plants are widely distributed in dry environments and endemic to Mexico. These plants have a rosette formation and varied leaf colors and shapes, which are characteristics of interest for landscaping, cut flowers, or interior decoration. Given their range of locations in different climates or indoor conditions, it is important to have an understanding and knowledge of their leaf morphology and anatomy and how they function to provide optimum care and management. Owing to high demand in horticultural markets, many breeders have crossed their desired species. However, this method has progressively increased the number of species without proper records of parents or other natural unintended crossings, creating phylogenetic problems and identification issues. The use and understanding of phenotypes, anatomical data, and/or research to aid in taxonomic issues and improve cultural management practices have been reviewed and discussed in this paper. In this review, we have provided a brief background of Echeveria species, focusing on the challenges and studies that have attempted to address these issues.

양액 pH가 에케베리아 생육과 색상에 미치는 영향을 알아 보기 위해 본 연구를 수행하였다. 에케베리아 ‘Perle von Nurnberg’ 품종을 선택하여 미국 유타주 프로보(Provo)시 소재 브리검영대학교 Plant and Wildlife 학과의 연구온실에서 수행되었다. 이 품종에 pH 4, pH 7 및 pH 10 3종류의 양액을 공급하여 연구를 수행하였다. 양액 pH 4 처리구에서는 초폭이 120.6mm로 pH 10 처리구의 105.3mm 보다 크게 자랐으며 유의성도 있었다. 하지만 엽장, 엽폭, 엽수에 있어서는 처리간 유의성은 없었다. pH meter를 통해서 식물체 즙액의 pH 를 측정하였는데 4.5에서 4.7 범위의 값을 보였으며 처리간 유의성은 없었다. 위의 결과로 양액의 pH는 식물체의 pH에 영향을 미치지 않는 것으로 판단되었다. 색차계를 이용하여 CIELAB 값을 측정하였을 때 pH 4 처리구에서의 적색도(a)는 -4.0이었으며 pH 10 처리구보다 더 녹색을 띠었다. 명도(L)과 황색도(b) 값은 처리간에 유의적인 차이가 없었다. HPLC를 통한 안토시아니딘 분석에서는 주로 cyanidin, delphinidin 및 pelargonidin의 함량이 모든 처리구에서 상대적으로 높게 나타났다. 공급양액의 pH가 상승함 따라 그 함량도 높아지는 경향을 보였다. Petunidin, malvidin 함량은 미량으로 존재하였으며, peonidin은 분석되지 않았다. 이상의 결과로부터 양액을 pH 10으로 처리하였을 때 에케베리아의 생육억제와 잎 착색에 가장 효과적임을 알 수 있었다.

Succulents are ornamental plants that are popularly used in landscaping and as potted plants. Miniatureplants that are planted in miniature pots for small spaces or tables, or in elaborateaccessories such as key chains, key holders or hanging pots, have recently become more popular. Their unique characteristics and aesthetic appeal have increased their demand especially for those species that do not grow extensively during transport or for special cases in which they are placed into tiny containers to be used in key chains. This study investigated the effects of the plant growth inhibitors chlormequat, paclobutrazol, and daminozide, on two Echeveria species, Echeveria ‘A Grimme One’ and Echeveria ‘Little Rose’. Results revealed that the plant growth inhibitors successfully controlled the growth of Echeveria species at specific concentrations. Among the inhibitors applied to the succulents, paclobutrazol at 100 ppm was found to be the most effective treatment for both the species.

Few studies have reported how temperature influences growth and development of succulents, including anthocyanin production, which could fetch better prices in the market, and understanding the factors influencing such pigments would benefit farmers. The present study investigated the effect of temperature (10°C, 20°C, and 30°C) on the growth, development, and anthocyanin concentrations in Echeveria agavoides and E. marcus. In E. agavoides, similar growth performance was observed at 10°C and 20°C based on plant height and diameter. However, subjecting the species to a high temperature of 30°C resulted in a decrease in plant height. In E. marcus, optimal growth performance was observed at 20°C. Different temperatures did not significantly affect succulent quality and color hues. Only L* values were significantly different among the Hunter’s Lab values. Similar results were observed following anthocyanin and image analyses, both of which were not significantly affected by temperature. However, an intense red pigment was observed at 20°C compared with the green pigment observed at 10°C and 30°C based on the image analysis. The results suggest that temperature influences growth, development, and anthocyanin content of Echeveria succulents, and 20°C could be the optimal temperature for the cultivation of the species.

다육식물인 에케베리아(Echeveria)는 최근 전세계적으로 수요가 증가하고 있지만, 번식효율이 품종이나 환경 요인의 영향을 크게 받으므로 연중 고품질 묘를 공급하는 것이 어렵다. 이 연구는 밀폐형 식물공장 내에서 LED 파장 조합이 에케베리아 엽삽번식 효율에 미치는 영향을 구명하여 주년 생산의 기초자료를 제공하고자 실시되었다. 번식이 어려운 ‘Afterglow(AG)’, ‘Berkeley Light(BL)’, ‘Mason(MS)’, ‘Subsessilis Light(SL)’, ‘Cream Tea(CT)’, ‘Ben Badis(BB)’ 등 6품종의 모주로부터 균일한 잎을 채취하여 실내온도 24±2℃, 상대습도 60±10%의 식물공장 내에서 혼합상토에 삽목하였다. 청색(B, 450nm), 녹색(G, 530nm), 적색(R, 660nm), 원적색(FR, 730nm) LED를 이용하여 R10, R8+B2, R5+B5, R7+B2+FR1, R7+B2+G1의 비율로 광질을 달리하여 처리하였고, PPFD는 200μmol·m-2·s-1, 광주기는 16/8(명/암) 시간이었다. 그 결과, 번식 효율은 품종에 따라 차이가 있었는데, ‘SL’은 상대적으로 발근과 신초 형성이 쉽게 되었으나, ‘AG’는 발근과 뿌리 생장이 잘 되지 않았다. LED 파장 또한 번식효율에 영향을 주었는데, B 비율이 높은 R5+B5, R7+B2+FR1, R7+B2+G1 하에서 신초 형성과 생장이 촉진된 반면, 발근과 뿌리 생장은 억제되었다. 반대로, R 비율이 높은 R10나 R8+B2 하에서는 부정근 형성 및 생장이 촉진된 반면, 신초 형성 및 생장이 억제되었다. 한편, FR은 잎의 크기와 무게를 증가시켰다. 따라서, 번식이 어려운 에케베리아 품종의 엽삽 시 번식 효율을 높이기 위해서는 각 파장별 효과를 활용한 적정 파장 조성에 대한 연구가 필요하다.

Shading is a key element in the control of light intensity and is usually used during the summer when sunlight is at its most intense. Succulents are ornamental crops that have beextremely popular because of their leaf structure and other characteristics. A study was conducted to determine the effects of shading on the growth and development as well as the anthocyanin content of two Echeveria species: Echeveria agavoides and E. marcus. Three levels of shading were used, namely no shading/full light treatment, partially shaded conditions, and well-shaded conditions, which were achieved by placement inside controlled growing chambers for 4 weeks. The results revealed the bolting of growth in both height and diameter for both species when grown under shaded and partially shaded conditions, which were abnormal compared withthe typical development. CIELAB color results also showed thata* was significantly affected by shading levels, exhibiting a higher positive value for succulents under full light or no shading. These results were consistent with the anthocyanin analysis, where the highest contents were identifiedinthe species grown under full light. The image analysis also confirmed a higher percentage area based on the smart segmentation for red pigments compared withthat for green pigments.

This study was conducted to determine the effects of light intensity on the growth and development as well as the anthocyanin content of two Echeveria species, namely Echeveria agavoides and E. marcus. Three light intensity levels (high, 150 μmol･m-2s-1; intermediate, 75 μmol･m-2s-1; and low, 35 μmol･m-2s-1) served as the treatments, which were replicated four times. The results revealed that the tallest and largest plants were those under low light conditions. It was observed that there was a decline as the light intensity increased, which is attributed to the coping mechanisms of plants to search for light sources, which has a similar effect to bolting or an increase in the node-to-node distance. CIELAB color values of L* and a* for both species were significantly affected by the light intensity, indicating changes in the lightness of hue and green-to-red color pigmentation in plants. These results were strongly reflected in those of the anthocyanin content analysis, where a direct increase in the concentration was observed with increasing light intensity. The results of the anthocyanin analysis were also supported by the histogram, smart segmentation images, as well as the ratio of red and green pigments found in the images. Thus, a high light intensity should be used to increase the quality and provide conducive growing conditions for both succulent species.

A study was conducted to evaluate the effects of auxin, cytokinin, and their combined application to hasten their propagation using leaf cuttings. Different hormone levels were evaluated on two Echeveria species (E. subsessilis and E. runyonii). Three levels of auxin as represented by the use of indole-3-butyric acid (IBA) (0, 100, and 500 ppm), three cytokinin levels as represented by Kinetin (Ki) (0, 100, and 200 ppm) and their combination were applied and observed for 8 weeks. The use of 100 ppm IBA resulted in the highest shoot height, diameter, and rooting and shooting rate. Using 500 ppm IBA led the roots to develop the earliest but both species also had the highest mortality. The application of 100 ppm Ki significantly affected the majority of leaf cuttings of E. runyonnii which exhibited the highest and thickest shoots, and the number of leaves. The application of 100 ppm IBA and 100 ppm Ki is recommended to obtain increased shoot growth and development for leaf cuttings. In the case of single hormone use, the application of 100 ppm IBA may be preferable. The combination of auxin and cytokinin significantly stimulated the hastening of production of succulents using leaf cuttings.

Growth and development of succulents were studied in response to two leaf cutting types, the tip and base, using four Echeveria species (E. ‘A Grimm One’, E. ‘Momorato’, E. pulvinata ‘Frosty’, and E. pulidonis) and the planting position, either upright and faced-downward, using Graptoveria optalina. The shoot diameter (mm), height (mm), and number of leaves were significantly affected by the leaf cutting type. Results revealed that the shoot diameter of buds from base leaves were significantly larger by 4 - 9 times than those of buds from tip leaves. Shoot height of buds from tip leaves either not developed or reached a maximum of 2.29 mm while buds from base leaves had an average height of 11.61 mm from E. ‘Mamorato’. Using base leaves allowed to obtain roots and leaves for all selected succulent species after 60 days from planting. Regarding planting position, upright planted and downward-facing plants showed significant differences: buds from upright planting showed taller shoots, greater number of leaves which in turn gave higher visual quality rating and superior color reading using Hunter’s Cielab compared with buds in downward-facing planting position. Planting succulents in an upright position led to well-formed shoots and roots which had a high-quality rating and color evaluation compared with faced-downward planting producing etiolated and abnormal grown shoots. Based on these findings, we suggest that the use of base leaf cuttings and an upright planting position provides a rapid vegetative propagation method for selected succulent varieties.