Plant Maturity Affects Flowering Ability and Flower Quality in Phalaenopsis, Focusing on Their Relationship to Carbon-to-nitrogen Ratio

In the commercial production of phalaenopsis orchids, the cultivation time after deflasking is used to describe the plant age and maturity. Carbon-to-nitrogen (C/N) ratio is often used as an indicator of plant growth and flowering potential. High C/N ratios are considered to promote reproductive growth, and low C/N ratios are associated with the early vegetative growth or even inhibiting flowering. This study investigated how plant age and maturity affected flowering ability and flower quality of phalaenopsis and their relationship to C/N ratio. The plant materials of various ages were the purple, small-flowered Phalaenopsis Sogo Lotte ‘F2510’ and white, large-flowered P. Sogo Yukidian ‘V3’, which were 2 to 7 months and 10 to 20 months after deflasking, respectively. Plants were placed under 25/20 °C for 4 months to force flowering and investigate the flowering-related parameters. The leaf C/N ratio of both varieties increased in general with the increase of plant age. The spiking (flower-stalk emergence) rate of P. Sogo Lotte ‘F2510’ 2 months after deflasking was only 42%, which indicates that these plants were not completely out of their juvenile phase, whereas that of those 3 to 7 months after deflasking was 100%, indicating that plants had acquired full flowering ability. No linear correlation was found between the C/N ratio and days to spiking, to first visible bud, to first flower open, and to 90% flower opening in the white, large-flowered P. Sogo Yukidian ‘V3’. However, there was a positive correlation between the C/N ratio and inflorescence length, flower-stalk diameter, first flower diameter, and flower count. Thus, the C/N ratio is feasible to be used as an indicator for assessing the flowering quality in phalaenopsis.

Plant age, crop stage and surrounding habitats: their impact on sucking pests and predators complex in cotton (Gossypium hirsutum L.) field plots in arid climate at district Layyah, Punjab, Pakistan

Sucking pests are major threat to cotton field crop which cause unbearable losses to the crop yield. Aim of the current study was to record seasonal dynamics of major sucking insect pests including whitefly, jassid, thrips and their natural arthropod predators i.e. green lacewings and spiders in cotton field plots. The effects of surrounding field crops on pests’ density and predatory efficiency of predators were also recorded. For sampling and survey of insects, the visual counting was found to be the most efficient method for recording the abundance of insects, trailed by net sweeping and tapping. Whitefly was the most dominant sucking pest found on the vegetative stage of cotton, followed by jassid and thrips. Fluctuated populations of predatory arthropods, spiders and green lacewings were also recorded during whole cropping season however, the densities of pests and predators varied with crop phenology. Spiders’ population was encouraging at both vegetative and flowering stage and also the same trend of jassid and whitefly were observed at both stages of the crop. Surrounding habitats showed non-significant effect on population densities of insect pests and predators. For abiotic factors, the spiders showed strong positive correlation with humidity and temperature. However, green lacewing was only positively correlated with humidity. On the other hand, the populations of whitefly, jassid and thrips showed non-significant correlation with both temperature and humidity. Overall densities of sucking insect pests were found above economic threshold level. The plant age, crop stage and surrounding habitats effect on the population fluctuation of pests as well as the predators’ abundance. The future studies are also warranted to investigate the altered habitats and multiple trap cropping to find out their impact on unattended insect predators and parasitoids in cotton crop.

Sugar content variation in elephant grass germplasm

ABSTRACT: The objective of this study was to estimate sugar content variation (°Brix) in 95 accessions from the elephant grass germplasm active bank of Embrapa Dairy Cattle research center, located in Coronel Pacheco, MG, Brazil. The accessions with the highest sugar content were identified, and the effect of plant age on sugar concentration was evaluated. The experiment was conducted in randomized blocks design with two replications. Sugar content analysis occurred twice during the growth-cycle (at 70 and 100 days) along two points of the stem, one 30 cm from the base and the other at the midpoint. The analysis of variance considered the split plot model, with accessions as main plots and plant age as subplots. The means were compared using the Scott Knott test. While there was sugar content variation between accessions, increased plant age had no significant effect on the sugar content. However, some accessions did have a significant increase or decrease in sugar content as they aged. The highest and lowest mean sugar content was 6.96% (in the accession BAG80) and 4.03% (in the accession BAG13) °Brix, respectively.

Plant age at the time of ozone exposure affects flowering patterns, biotic interactions and reproduction of wild mustard

Exposure of plants to environmental stressors can modify their metabolism, interactions with other organisms and reproductive success. Tropospheric ozone is a source of plant stress. We investigated how an acute exposure to ozone at different times of plant development affects reproductive performance, as well as the flowering patterns and the interactions with pollinators and herbivores, of wild mustard plants. The number of open flowers was higher on plants exposed to ozone at earlier ages than on the respective controls, while plants exposed at later ages showed a tendency for decreased number of open flowers. The changes in the number of flowers provided a good explanation for the ozone-induced effects on reproductive performance and on pollinator visitation. Ozone exposure at earlier ages also led to either earlier or extended flowering periods. Moreover, ozone tended to increase herbivore abundance, with responses depending on herbivore taxa and the plant age at the time of ozone exposure. These results suggest that the effects of ozone exposure depend on the developmental stage of the plant, affecting the flowering patterns in different directions, with consequences for pollination and reproduction of annual crops and wild species.

Variasi Umur Tanaman Reklamasi Terhadap Struktur dan Komposisi Vegetasi di Areal Reklamasi Tambang PT Kideco Jaya Agung, Paser, Kalimantan Timur

Salah satu indikator yang digunakan untuk mengukur keberhasilan kegiatan reklamasi adalah dengan cara menghitung jumlah jenis vegetasi yang tumbuh pada areal reklamasi tersebut. Penelitian ini bertujuan untuk mengkaji variasi umur tanaman terhadap struktur dan komposisi vegetasi di areal reklamasi tambang (KRPT) PT Kideco Jaya Agung (PT KJA), Paser, Kalimantan Timur melalui kegiatan monitoring dan evaluasi vegetasi tahunan. Lokasi studi mencakup 13 (tiga belas) KRPT dengan umur tanaman 1-13 tahun. Nilai kerapatan vegetasi tertinggi pada masing-masing kategori adalah 1.125 individu/ha (KRPT umur 12 tahun) untuk tingkat pohon, 650 individu/ha (KRPT umur 10 tahun) untuk tingkat pancang dan 525 individu/ha (KRPT umur 8 tahun) untuk tingkat semai. Hasil penelitian ini juga menunjukkan bahwa terdapat 51 jenis vegetasi yang berasal dari 22 famili tanaman ditemukan pada areal konsesi PT KJA site Roto Samurangau. Dimana 32 diantaranya merupakan jenis tanaman yang tumbuh secara alami, sedangkan 19 jenis vegetasi lainnya merupakan jenis tanaman pokok. Berdasarkan variasi nilai kuantitatif pada masing-masing lokasi yang diamati, tidak tampak bahwa semakin tua umur tanaman, maka semakin tinggi pula nilai kerapatan vegetasi, basal area, dan kehadiran jenisnya. Namun, meskipun secara umum menurun, keragaman jenis pohon pada tanaman reklamasi yang lebih tua cenderung lebih beragam. Hal tersebut dikarenakan berbedanya situasi dan kondisi masing-masing KRPT yang diamati, seperti perbedaan kondisi tanah, jenis tanaman, dan jarak lokasi studi dengan hutan alam. Berdasarkan hasil identifikasi dan inventarisasi yang dilakukan pada penelitian ini diketahui bahwa KRPT dengan umur tanam 12 tahun memiliki komposisi vegetasi yang paling beragam, dimana dari 19 jenis vegetasi, 14 diantaranya merupakan jenis tanaman yang tumbuh secara alami. ABSTRACTThe one indicator used to measure the reclamation succession activities is by calculating the number of vegetation species that grow in reclamation area. This study aimed to determined the variations in plant age on the vegetation structure and composition in the mine reclamation area (KRPT) of PT Kideco Jaya Agung (PT KJA), Paser, East Kalimantan through annual vegetation monitoring and evaluation activities. The study sites cover 13 (thirteen) KRPTs with a plant age of 1-13 years. The highest vegetation density values in each category were 1,125 individuals/ha (12 years old KRPT) for the tree level, 650 individuals/ha (10 years old KRPT) for the sapling level and 525 individuals/ha (8 years old KRPT) for the seedling level. Present study also showed that there were 51 species of vegetation from 22 plant families found in the concession area of PT KJA, 32 are naturally species while others 19 species are main vegetation. Based on the variation of quantitative values at each location observed, it was not appeared that the older plant age affected to the higher value of vegetation density, basal area, and species presence. However, although it was generally declined, tree species diversity in older reclaimed plants tended to be more diverse. This is probably due to the different situations and conditions of each observed KRPT, such as differences in soil conditions, plant species, and the distance between study site and natural forest. The result of plant species identification and inventory showed that KRPT with a planting age of 12 years had the most diverse vegetation composition, where from 19 species there are 14 species of them grown naturally

Under Attack: Fungal Landscape of Spring Barley From Seedling Emergence to Harvest During a Severe Puccinia Hordei Epidemic

All plant tissues from leaves, stems and roots are hosting a wide diversity of fungal species. Our understanding of the assembly of this diversity of fungi during the plant growth cycle is limited. Here, we characterized the mycobiome of three spring barley cultivars at weekly intervals from seedling emergence to senescence and seed maturity. A notable proportion of members of the fungal communities were shared among different plant organs, but community dynamics were tissue specific. A severe attack of Puccinia hordei occurring during the vegetative stage had profound effects on the mycobiome, and P. hordei biomass displaced that of other taxa. Plant tissue type was the most important factor determining the mycobiome, but also plant age was contributing significantly. Using a random forest model, we found that specific members of the mycobiome were responding differently to plant age. A co-occurrence network analysis revealed complex interactions among fungal OTUs, and network connectivity was changing as per plant growth stage and plant tissue type. This study contributes to the understanding of assembly of fungal communities in cereals by providing a detailed atlas of fungal communities associated with barley. This knowledge will be vital for microbiome assisted plant health management and our study will serve as an important baseline for future efforts to harness microbiota in cereal health.

Effects of Plant Age, Topography and Processing System On the Biochemical Traits and Quality of Tea

Laboratory experiment was conducted to study the biochemical and quality parameters of tea i.e. Polyphenol, Theaflavin (TF), Thearubigin (TR), Caffeine, Lipid, Total ash, Chlorophyll, Moisture content etc. under different variables designed for age, topography, and processing system imposed on an established tea orchard. Results revealed that plant age and topography do not have any significant effect on most of the studied parameters. In case of plant age, tannin is found to be significantly higher in mature tea plant (39.35 ppm) whereas young plant showed significantly lower total sugar content (28.98 ppm). In case of land elevation, significantly higher tannin (37.41 ppm) and lower carotenoid content (0.74 mg/g) were evident in plants from kunchi topography where flat topography showed significantly higher total sugar (26.62 ppm) in leaves. The handmade tea flavoured with significantly higher amount of polyphenol (58.57 ppm) and caffein (43.30 ppm) but industry made tea showed significantly higher amount of tannin (37.65 ppm), total sugar (15.25 ppm) and TF:TR (1:10). Bangladesh J. Bot. 50(3): 633-639, 2021 (September)