Tree peonies (Paeonia suffruticosa Andr. and hybrids) are well-known ornamental and medicinal plants cultivated in temperate and subtropical regions around the world. From June to September 2021, severe leaf spot disease was observed on 3 tree peony cultivars (‘Luoyanghong’, ‘Moyushenghui’, ‘Roufurong’) in Xinxiang (35º29´N, 113º95´E) and Luoyang (34º64´N, 112º49´E), Henan Province, China. Leaf spot incidence was as high as 28% (‘Luoyanghong’), 45% (‘Moyushenghui’) and 67% (‘Roufurong’), respectively. Symptoms appeared initially as small purple spots less than 1 mm in diameter in the middle and upper parts of the leaves, and then evolved to coalescent lesions, causing brown scorch ultimately. From each cultivar, 5 diseased leaves were collected. Leaflet tissues (3-4 mm2) cut from spot margins were surface sterilized in 75% alcohol for 45 s, washed 5 times with sterile distilled water, and then cultivated on potato dextrose agar (PDA) medium at 28 °C in the dark. Eleven isolates were obtained, and colonies grown from single conidia on PDA were 80-85 mm in diameter after 10 d, with scattered small, dark-based spikes on the surface of the colonies. The aerial mycelium was cottony, dense, and dark gray near the center on the reverse side. Conidia were cylindrical to clavate, with rounded apex and rounded base, and the conidia contents were granular, 8.44-14.06×3.60-4.31 μm (mean=11.28×3.69 μm, n=40). Appressoria were mostly subglobose or with a few broad lobes, pale to medium brown, 3.36-6.72×3.35-5.60 μm (mean=5.02×4.55 μm, n=20). Based on the culture representation and conidial morphology, the isolates were characterized as Colletotrichum gloeosporioides species complex (Weir et al. 2012; Fu et al. 2019). To further identity the species, the actin (ACT), calmodulin (CAL), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and the ribosomal internal transcribed spacers (ITS) loci of isolates PSW0002, PSW0008 and PSW0009 were amplified using ACT-512F/ACT-783R, CL1C/CL2C, CHS-79F/CHS-345R, GDF/GDR, and ITS1/ITS4, primers (Weir et al. 2012; Schena et al; 2014; Kim et al. 2021; Li et al. 2021). Fifteen sequences were deposited in GenBank (ACT for OP225605, OP225606, and OP225607, CAL for OP225608, OP225609 and OP225610, CHS for OP225611, OP225612 and OP225613, GAPDH for ON321897, OP225614, and OP225615, and ITS for ON323473, OP214349 and OP214350 ), which showed 100% sequence similarity to Colletotrichum aenigma (JX009443 and JX009519 for ACT, JX009683 and JX009684 for CAL, JX009774 and JX009903 for CHS-1, JX010244 and JX009913 for GAPDH, JX010243 and JX010148 for ITS). Three isolates clustered with C. aenigma (ex-holotype culture ICMP 18608) in the multi-locus phylogenetic tree with a bootstrap value of 100%. To achieve Koch's postulates, pathogenicity was tested on 5-year-old healthy potted plants (‘Luoyanghong’). Thirty leaves were inoculated with 10 µL conidial suspension (isolate PSW0002, 1×106 conidia/mL) and the controls were inoculated with sterile water. Plants were placed in a greenhouse at 28°C under conditions with 12 h photoperiod and 90% relative humidity. After 5 to 10 days, distinct spots were observed on the inoculated leaves, while the control leaves showed no symptoms. C. aenigma was reisolated from all inoculated leaves, but not from the control. C. aenigma has been reported to cause anthracnose on Pyrus pyrifolia (Weir et al. 2012), Camellia sasanqua (Chen et al. 2019), Juglans regia (Wang et al. 2020), Paeonia ostii (Ren et al. 2020), and Capsicum annuum (Sharma et al. 2022). A previous study reported C. gloeosporioides as a pathogen of anthracnose in tree peonies in China (Xuan et al. 2017), the typical symptoms were big necrotic lesions (5-10 mm diam) on leaves，which were significantly different from those caused by C. aenigma. To our knowledge, this is the first report of C. aenigma causing anthracnose in tree peonies in China. This finding may help to take effective control of anthracnose in tree peonies.

Background Lavender flowers essential oil had been for a variety of therapeutic and cosmetic purposes, and had been popular for centuries. The previous studies of lavender mainly focused on essential oil composition and extraction methods, ignoring the factors which affected the production of essential oils, such as the floret number. This study aims to get a deeper insight into florets number difference mechanism. Results Hormone profile showed positive correlation between ABA content and the number of florets while IAA was negatively correlated. RNA-Seq results showed that 2848 differentially expressed genes screened by comparing different florets samples in one plant. By analyzing dynamic changes of differentially expressed genes, many potentially interesting genes were identified that encoded putative regulators or key components of ABA metabolism and signaling transduction, such as NCED, PYL, PP2C, SnRK2. These genes were highlighted to reveal their importance in regulation of florets numbers. Conclusions 1. The different ABA concentrations lead to florets difference in the Lavandula angustifolia “JX-2” clusters; 2. ABA may affect the florets number by regulating IAA transport and accumulation. The results will be useful for a better understanding of the molecular mechanism on florets number difference that could be laid the foundation for molecular breeding of muti-flortes varieties.

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The garden pansy (Viola × wittrockiana) is a large hybrid flower and most popular for its abundant flower colors. The flower colors of 12 pansy accessions were measured by using colorimeter and the pigments distribution within their petal cells were investigated. The result indicated a vast majority of the visual color of flower was consistent with the result surveyed by colorimeter in pansy. The pigments were mainly distributed in the upper and dorsal epidermal cells and most of them show the similar colors to those measured using colorimeter. The red pigment was found to be distributed in the visual blue petals and yellowish brown or khaki pigment in visual white petals. The results suggested the flower color of pansy can be objectively and accurately measured with colorimeter, and investigating pigment color and distribution in petals can help understanding pansy flower color better.

Pansy is a good potential resource for natural pigments due to its rich flower colours. In the present study, pigment from a pansy breeding line, E01, was extracted and its solubility in different reagents and stability under various environmental conditions were investigated. The pigment extracted displayed watersoluble property and was also dissolved in acid (HCl) and alkaline (NaOH) reagents and relatively polar solvents, but insoluble in nonpolar solvents. The pigment-water solution had an absorbance peak at 238 nm with amaranthine colour under acidic conditions. It was stable in aqueous solution under normal conditions. However, it was easily spoiled when exposed to high pH (> 4), high temperature (> 80℃) or under intense light exceeding 170000 lx. The stability of pigment was significantly influenced by Cu2+, but scarcely affected by Na+, Mg2+ and Ca2+. These results will be helpful for commercial prospects of pansy pigment in natural food colour industry. Bangladesh J. Bot. 51(3): 433-438, 2022 (September)