Differential Effects of Paclobutrazol on the Bulblet Growth of Oriental Lily Cultured In Vitro: Growth Behavior,Carbohydrate Metabolism,and Antioxidant Capacity

Bulblet growth is crucial for global lily production, and the applications of plant growth regulators have proven effective but with poor understanding of mechanisms. The aims of this study were to identify the effects of paclobutrazol (PBZ) on tube lilies. Low PBZ concentrations (5 × 10⁻⁴ mM, LPBZ) stimulated bulblet biomass, whereas higher doses suppressed the growth of the leaves and roots. Soluble carbohydrate and starch contents increased significantly with increased PBZ dose. The activities of adenosine 5′-diphosphate glucose pyrophosphorylase (AGPase), granule-bound starch synthase (GBSS), and soluble starch synthase (SSS) increased dramatically in response to PBZ treatments at later growth stages (60 days after transplanting) when carbon starvation occurred. In contrast, GBSS activity was enhanced throughout the whole growth period, indicating that the starch increase was attributed mainly to amylose synthesis. Carbohydrates were utilized more efficiently following LPBZ, with a relative bulblet weight of approximately 77.07%, which potentially ensured the source-sink balance. Alternatively, more carbohydrates were stored in response to high PBZ concentration. Intriguingly, PBZ usage significantly increased the activities of ascorbate peroxidase, catalase and glutathione reductase at the early stages, implicating a possible role in the elimination of ROS to maintain homeostasis. Application of LPBZ resulted in the largest bulblet, which weighed 396 mg (2.5 times that of the control) and measured 10.70 mm in diameter. The detailed characterizations of the bulblet swelling mechanism using PBZ in vitro offer suggestions of future PBZ usage in other bulbous crops.

     

A new miniature species of the genus Triplophysa (Balitoridae: Nemacheilinae) from Yunnan, China

During a re-examination of museum specimens of Triplophysa species, some specimens that had been collected from the Jialonghe River in Yunnan Province, China, in April 1975, were identified as a new species. Triplophysa parvus n. sp. can be distinguished by the following combination of characters: dorsal fin rays 3, ; anal fin rays 3, ; pectoral fin rays 1, 11; scales absent; two saddle-like blotches with fuzzy borders cranial to the dorsal fin and four saddle-like blotches caudal to the dorsal fin; distal margin of the dorsal fin emarginate; pelvic fin reaching caudally almost to the anus; anus located immediately cranial to the origin of the anal fin; caudal fin forked; caudal chamber of air bladder reduced to a small free protuberance; head slightly laterally compressed, head deeper than wide at nape; length of caudal peduncle being 18.0–20.0% of standard length; depth of caudal peduncle being 7.8–8.4% of standard length; eye diameter 17.6–21.4% of head length; body depth being 60.7–70.2% of head length; caudal peduncle depth being 39.1–45.0% of caudal peduncle length; and body width at the base of caudal peduncle 59.0–68.0% of the body depth at the base of caudal peduncle. These characters allow a distinction from the similar species of T. nasobarbatula, T. nandanensis, and T. macromaculata.     

A new cyprinid species, Placocheilus dulongensis, from the upper Irrawaddy system in northwestern Yunnan, China

A new species of the cyprinid genus Placocheilus Wu 1977, is described from the Dulong River drainage (in the upper reach of the Irrawaddy River), northwestern Yunnan Province (China). Placocheilus dulongensis sp. nov. can be distinguished from the other three congeners, namely P. caudofasciatus, P. robustus and P. cryptonemus, by the following combination of characters: no semicircular black mark on the middle of each caudal fin lobe; no blackish band across the dorsal fin; one pair of rostral barbels and one pair of maxillary barbels; 39-40 perforated lateral line scales. Osteological characters, such as the shape of the second infraorbital, preoperculum, and the vertical plate of the urohyal were observed in a cleared and stained skeletal specimen. A simplified key to the genus Placocheilus is provided based on the comparisons among the four species.     

A morphologically variant natural population of cyprinids without dorsal fin possibly derived from Mystacoleucus marginatus (Osteichthyes: Teleostes) from the Lancang Jiang River, Yunnan, China

In July 2001, 15 grotesque cyprinid specimens were collected in the Lancangjiang River (of the upper reaches of the Mekong River) in Menglun Town, Xishuanbanna Prefecture, Yunnan Province, PR China. These specimens are characterized by surprising characters that have not been observed in natural populations of cyprinids previously, such as an absence of a dorsal fin and of some supraneurals. Other characters, such as the number of branched rays of the anal fin, the formula of pharyngeal teeth, the condition of barbels, and the number of scales are not stable and vary greatly. The more stable characters of these variants, such as the formula of pharyngeal teeth, the pattern of striations on the scales, the number of vertebrae, the length of the gut, etc., have many similarities with those of Mystacoleucus marginatus (Cuvier & Valenciennes, 1842). These observations indicate that these variants may have originated from M. marginatus.     

A New Species of the Genus Tor from Yunnan, China (Teleostei: Cyprinidae)

A new species of the subfamily Barbinae, Tor yingjiangensis, is recognized from Yunnan province, China. It can be distinguished from other Tor species by the following combination of characters: last simple dorsal-fin ray osseous and non-serrated; no forward directed predorsal procumbent spine; head length considerably longer than body depth; no tubercles on the snout or sides of the face; 18–20 gill rakers on the outside of first gill arch; 24–26 lateral line scales; median lobe of lower lip short, its posterior margin truncate, not extending to the vertical across the inner corners of the mouth; and the condition of the lower lip consistent in individuals of different sizes. The new species has been misidentified previously as Tor putitora (Hamilton, F. 1822. An account of the fishes found in the River Ganges and its Branches. Edinburgh & London. 405 pp), which occurs in the Ganges and Indus River basins. The new species can easily be distinguished from T. putitora by having 3–3.5 (vs. 2.5) scales from lateral line to pelvic-fin origin, shorter caudal peduncle length (13.0% vs. 17.2% of standard length), lesser body depth (26.4% vs. 24.0% of standard length) and longer caudal peduncle depth (12.0% vs. 10.9% of standard length), no longitudinal stripe present along side of body, and eyes visible in ventral view of head.