Impacts of Fall Nitrogen Application on Seed Production in Leymus chinensis , a Rhizomatous Perennial Grass

2013 ◽  
Vol 105 (5) ◽  
pp. 1378-1384 ◽  
Author(s):  
Junfeng Wang ◽  
Xiaoyu Li ◽  
Song Gao ◽  
Zhuolin Li ◽  
Chunsheng Mu
2010 ◽  
Vol 32 (4) ◽  
pp. 419 ◽  
Author(s):  
Xing Teng ◽  
Lei Ba ◽  
Deli Wang ◽  
Ling Wang ◽  
Jushan Liu

Many studies indicated that saliva from herbivores might be involved in plant growth responses when plants have been grazed. However, there is currently no general agreement on whether saliva can affect plant growth. Our aims were to determine the growth response of plants to sheep saliva after defoliation under diverse environmental conditions (different sward structures), and whether the effect of saliva is influenced by time (duration) after its application. We conducted field experiments with clipping treatments and the application of sheep saliva to the damaged parts of tillers to simulate sheep grazing on the perennial grass Leymus chinensis (Trin.) Tzvelev during the early growing seasons. Results demonstrated that clipping with saliva application significantly increased tiller numbers 8 weeks after treatments in comparison with clipping alone. A key finding is that the effect of sheep saliva on plant growth was short-lived. Clipping with saliva application increased leaf weight in the second week, while clipping alone had no effect. Moreover, clipping with saliva application promoted the elongation of new leaves (not the old ones) in the first week whereas clipping alone was ineffective. Results also showed that there were no differences between clipping with saliva application and clipping alone for relative height growth rate and aboveground biomass. Therefore, we concluded that saliva application to clipping treatment would produce an additional effect compared to clipping alone for the plant and the positive effects are time dependent. The additional effects primarily embodied in the individual level of plant, such as the changes of leaf weight and leaf length. Beyond the level, the effects of saliva only produced many more tiller numbers rather than the accumulation of aboveground biomass.


2001 ◽  
Vol 49 (6) ◽  
pp. 735 ◽  
Author(s):  
Gabriel M. Crowley ◽  
Stephen T. Garnett

Alloteropsis semialata (R.Br.) A.Hitchc. is one of the first perennial grasses in monsoonal Australia to produce seed at the start of the wet season. Patterns of growth and seed production and seed dynamics of Alloteropsis semialata were examined in this study, along with the effects of partial defoliation. Growth of Alloteropsis semialata tussocks started with the first pre-wet-season rains, and was then interrupted during a period with little rain. Growth ceased before the end of the wet season, indicating that factors other than moisture availability were limiting. Seeds of Alloteropsis semialata were germinable on production, but did not remain viable or persist on the soil surface through the dry season. Most seeds and young seedlings were harvested and no seedlings were recruited. Inflorescence production increased with plant size. Moderate defoliation in the early wet season had no impact on plant growth, but reduced inflorescence and seed production for at least 2 years. Absence of a seed bank and early wet-season flowering mean that Alloteropsis semialata is likely to be sensitive to long-term over-grazing.


2014 ◽  
Vol 106 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Yunhua Han ◽  
Tianming Hu ◽  
Xianguo Wang ◽  
David B. Hannaway ◽  
Jun Li ◽  
...  

2019 ◽  
Vol 41 (5) ◽  
pp. 383 ◽  
Author(s):  
Vinod K. Chejara ◽  
Paul Kristiansen ◽  
R. D. B. (Wal) Whalley ◽  
Brian M. Sindel ◽  
Christopher Nadolny

Hyparrhenia hirta (L.) Stapf (also known as Coolatai grass, South African bluestem or thatching grass) has become a serious invasive weed in Australia. Within its native range, it is generally regarded as a useful grass particularly for thatching, and seed production is low with a low soil seed bank of from 2 to 200seedsm–2. Several hundred accessions of H. hirta were deliberately introduced into Australia up until the 1980s and nearly all were discarded because of poor seed production. However, at least one introduction in the 1890s in northern New South Wales (NSW), Australia, has possibly contributed to the present serious weed problem. Annual seed production from roadside stands in northern NSW ranged from 7000 to 92000seedsm–2 in 2015. The soil seed bank under dense H. hirta infestations in the same region in 2006 and 2007, was found to be ~30000seedsm–2 mostly confined to the top 2cm, with few dormant seeds and a large reduction of these numbers over the next 12 months when further seed input was prevented. Similar studies of other perennial grass weeds have found seed banks of similar sizes, but dormancy mechanisms ensure that their seed banks last for at least 10 years without further seed input. These results suggest that the present weedy populations of H. hirta have dramatically increased fecundity enabling a large seed bank to develop beneath dense stands. The development of seed dormancy and consequently a long-lived seed bank would make this weed even more difficult to control. Until seed dormancy develops, control of H. hirta in northern NSW can be effective provided further input into the seed bank can be prevented.


2019 ◽  
Vol 33 (6) ◽  
pp. 840-846
Author(s):  
Scott N. White

AbstractHair fescue is a widespread, seed-limited perennial grass in lowbush blueberry fields. Growers rely on pronamide, an expensive and difficult herbicide to use, for hair fescue management. Recent herbicide registrations provide opportunity to reduce pronamide use, though effects of these herbicides on hair fescue suppression and seedbank reduction are not well understood. The objectives of this research were to determine (1) the effects of herbicides currently registered in lowbush blueberry on suppression of hair fescue tufts and (2) whether suppression of hair fescue with these herbicides reduces hair fescue seedbanks. Pronamide gave the most consistent reductions in flowering tuft density, though applications after both autumn pruning and autumn of the nonbearing year were required to reduce the hair fescue seedbank by >60% across sites. Nonbearing-year hexazinone applications did not control hair fescue or reduce the seedbank. Nonbearing-year terbacil applications reduced flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. Glufosinate applications following autumn pruning or in the spring of the nonbearing year did not suppress hair fescue or reduce the seedbank. Spring nonbearing-year foramsulfuron applications, alone or after autumn or spring glufosinate applications, reduced hair fescue flowering tuft density, but hair fescue recovered in the bearing year, and the seedbank was not reduced. In contrast, autumn and spring glufosinate applications followed by spring nonbearing-year foramsulfuron applications, when combined with autumn nonbearing-year pronamide applications, reduced flowering tuft density in both the nonbearing and bearing years and reduced the hair fescue seedbank by 58% to 83% across sites. Results indicate that hair fescue seedbanks can be reduced in lowbush blueberry fields and that a reduction in pronamide use will require alternative bearing-year treatments to prevent tuft recovery and seed production.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xiliang Li ◽  
Zhen Zhang ◽  
Fenghui Guo ◽  
Junjie Duan ◽  
Juan Sun

Shoot defoliation by grazers or mowing can affect root traits of grassland species, which may subsequently affect its aboveground traits and ecosystem functioning (e.g., aboveground primary production). However, experimental evidence for such reciprocal feedback between shoots and roots is limited. We grew the perennial grass Leymus chinensis–common across the eastern Eurasian steppe–as model species in a controlled-hydroponics experiment, and then removed half of its shoots, half of its roots, or a combination of both. We measured a range of plant aboveground and belowground traits (e.g., phenotypic characteristics, photosynthetic traits, root architecture) in response to the shoot and/or root removal treatments. We found the regenerated biomass was less than the lost biomass under both shoot defoliation and root severance, generating a under-compensatory growth. Root biomass was reduced by 60.11% in the defoliation treatment, while root severance indirectly reduced shoot biomass by 40.49%, indicating a feedback loop between shoot and root growth. This defoliation-induced shoot–root feedback was mediated by the disproportionate response and allometry of plant traits. Further, the effect of shoot defoliation and root severance on trait plasticity of L. chinensis was sub-additive. That is, the combined effects of the two treatments were less than the sum of their independent effects, resulting in a buffering effect on the existing negative influences on plant persistence by increased photosynthesis. Our results highlight the key role of trait plasticity in driving shoot–root reciprocal feedbacks and growth persistence in grassland plants, especially perennial species. This knowledge adds to earlier findings of legacy effects and can be used to determine the resilience of grasslands.


2019 ◽  
Vol 70 (4) ◽  
pp. 373 ◽  
Author(s):  
Lihua Huang ◽  
Zhengwei Liang ◽  
Donald L. Suarez ◽  
Zhichun Wang ◽  
Mingming Wang

The effect of nitrogen (N) application on seed yields and yield components in Leymus chinensis (Trin.) Tzvel., a perennial rhizomatous grass, was measured in a field experiment with two saline-sodic soils at Da’an Sodic Land Experiment Station during 2010–11. Two grassland field sites were classified as moderately saline–sodic (MSSL) and severely saline–sodic (SSSL). Application rates of N at each site were 0, 30, 60, 90, 120, 150, 180 and 210 kg ha–1. Application of N significantly improved seed yield mainly through increased spike number (R2 = 0.96, P ≤ 0.001). Compared with nil N, seed yield increased 7.4–10.9 times with N application of 150 kg ha–1 at MSSL, and 5.3–7.5 times with N application of 120 kg ha–1 at SSSL. However, absolute increases at SSSL were relatively small. Some significant differences (P ≤ 0.01) in seed yield occurred between 2010 and 2011 with different N application rates in the same soil, and between MSSL and SSSL in the same year. Increasing N application rate significantly decreased N physiological efficiency (NPE) but increased N apparent-recovery fraction (NRF) and N partial-factor productivity (NPP) at both sites. Seed yield and NPP indicated that the optimal N application rates to increase yield were 150 kg ha–1 at MSSL and 120 kg ha–1 at SSSL. High soil pH was the major factor adversely impacting seed yield, and pH and soil salinity were major factors negative affecting NPE, NRF and NPP as well as decreasing the positive effect of N application. Nitrogen application is a practical and effective method to increase seed yield of L. chinensis in saline-sodic grasslands of Northeast China, particularly when soil pH and salinity are not limiting.


PLoS ONE ◽  
2013 ◽  
Vol 8 (7) ◽  
pp. e67974 ◽  
Author(s):  
Shuangyan Chen ◽  
Xin Huang ◽  
Xueqing Yan ◽  
Ye Liang ◽  
Yuezhu Wang ◽  
...  

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