Effect of Zn toxicity on root morphology, ultrastructure, and the ability to accumulate Zn in Moso bamboo (Phyllostachys pubescens)

Abstract

The effects of zinc (Zn) on seed germination and growth of Moso bamboo (Phyllostachys pubescens) were investigated. Under zinc stress, the seed germination rate did not show significant difference from that of the control. Hydroponics experiments indicated that Moso bamboo had a strong ability to accumulate Zn in the shoot and it reached its maximum value in the shoot at 100 μM Zn. The root Zn concentration ranged from 2,329.29 to 8,642.51 mg kg(-1), with the root Zn concentration at 10 μM Zn being 58.23 times that of the control. The root morphology parameters slightly increased at the lower Zn treatments, while growth restriction was evident at higher Zn treatments. Root ultrastructural studies revealed that the cell structure, root tips, and organelles were significantly changed under Zn stress as compared to those of the control. Some abnormalities were evident in the cell walls, vacuoles, mitochondria, plasmalemma, tonoplast, and xylem parenchyma of root cells. While Moso bamboo seems a suitable candidate for phytoremediation, its metal remediation ability should be further explored in future investigations.

Changes in root morphology and dry matter production in Pfaffia glomerata (Spreng.) Pedersen accessions in response to excessive zinc

“…At 14 days the accessions GD and JB showed a cubical response ( Figure 1H). Differences between root and shoot growth under Zn excess were also observed for the ecotypes of Holcus lanatus by Rengel (2000) and in Phyllostachys pubescens by Liu et al (2014). Disante et al (2010) reported reduction in leaf biomass of several woody species to excess Zn, as well as increase in root biomass production under relatively low levels of Zn.…”

“…Sharifianpour et al (2014) observed that among seven upland rice varieties, root parameters (length, average diameter, surface area, volume, and number of root tips) showed increased up 20 mg Zn L -1 , but they decreased significantly under 30 mg Zn L -1 after four weeks. Liu et al (2014) observed that root morphological parameters in Moso bamboo were initially increased by low levels of Zn, but on the other hand under Zn stress of 400μM, the length, surface area and volume of roots decreased 51%, 24% and 57%, respectively.…”

Effect of Zn stresses on physiology, growth, Zn accumulation, and chlorophyll of Phyllostachys pubescen s

“…The reduced contents of proline might be due to unknown ability of P. pubescens which decreased toxicity to Zn stress. Moreover, the mechanism of accumulation of proline in plants or plants parts exposed to stresses is still unknown (Choudhary et al 2007) The ability to accumulate Zn by P. pubescens in hydroponics experiment has been reported previously (Liu et al 2014). It showed good potential for P. pubescens as suitable candidate for phytoremediation.…”

“…Approximately 0.3 g of plant samples were processed by wet digestion under 135°C in 5 ml of 65 % HNO 3 (v/v) for 6-8 h. The digested solution was washed in 50-ml flasks and volume was made using de-ionized water. The supernatant was filtered through a 0.45-μm filter paper, acidified with 15 % HNO 3 and finally analyzed for Zn concentration by ICP-MS (Agilent 7500a) (Liu et al 2014).…”

“…P. pubescens has large biomass, quick growth rate, and can reach 82 t hm −2 of dry weight compared with other phytoremediation plants. Seed germination under Znstressed environment indicated that P. pubescens is a suitable candidate as phytoremediation material (Liu et al 2014).…”