Effects of Artificial Aging on Seed Vigor and Physiological Characteristics of the Invasive Alien Plant Aegilops tauschii

Abstract The control of invasive plants depends to some extent on the persistence of the soil seed bank. The high temperature (40 °C) accompanied with high humidity (95%) method was used to treat the seeds of the invasive species Aegilops tauschii Coss. The aim of our study was to evaluate the seed vigor and longevity by accelerating aging, to serve as a reference for the evaluation of invasion potential of A. tauschii and corresponding eradication strategy adoption. The results showed that with the extension of aging time, the germination rate (GR), energy (GE), and index (GI) of A. tauschii seeds reduced. All the results were significantly different from the control (CK) since the second day ( p < 0.05). During the aging process, the seed relative water content (RWC), relative electric conductivity (REC), and thiobarbituric acid (TBARS) level increased, while the superoxide dismutase (SOD) gradually decreased after second day of seed aging. In addition, the aging treatment also caused a continuous decrease in the endogenous gibberellin (GA 3 ) content and a continuous increase in the abscisic acid (ABA) content of the seeds. Thus, a sharp decrease in the GA 3 /ABA ratio was evident. Finally, the study revealed that the germination inhibitors of A. tauschii were mainly concentrated in the glumes, which was revealed during seed aging. The results of the comprehensive analysis indicated that the changes of the above-mentioned internal factors eventually led to a rapid decline of the seed vigor of A. tauschii . Based on the results of the aging test, and the distribution characteristics of A. tauschii seeds in the soil seed banks, we recommend that soil solarization is one of the effective methods to eradicate the seed bank of A. tauschii .

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Influence of Slope Direction on the Soil Seed Bank and Seedling Regeneration of Castanopsis hystrix Seed Rain

Forests ◽

10.3390/f12040500 ◽

2021 ◽

Vol 12 (4) ◽

pp. 500

Author(s):

Zong Zhao ◽

Yong Liu ◽

Hongyan Jia ◽

Wensheng Sun ◽

Angang Ming ◽

...

Keyword(s):

Seed Bank ◽

Temporal Dynamics ◽

Soil Seed Bank ◽

Soil Layer ◽

Seed Rain ◽

Seed Vigor ◽

Study Results ◽

The Impact ◽

Mature Seeds

Objective: To investigate the impact of different slope directions on the quantity and quality of the soil seed bank and seedling germination process of Castanopsis hystrix plantations. Method: Fixed sample plots in forest stands of Castanopsis hystrix were established on different slope directions (sunny slope, semi-sunny slope, semi-shady slope, and shady slope). The characteristics of the forest stand were investigated, and per-wood scaling was carried out. The temporal dynamics of the seed rain and seed bank were quantified using seed rain collectors and by collecting soil samples from different depths. The quantity and quality of the seeds were determined, and the vigor of mature seeds was measured throughout the study. Results: (1) The diffusion of Castanopsis hystrix seed rain started in mid-September, reached its peak from late October to early November, and ended in mid-December. (2) The dissemination process, occurrence time, and composition of the seed rain varied between the different slope directions. The seed rain intensity on the semi-sunny slope was the highest (572.75 ± 9.50 grains∙m−2), followed by the sunny slope (515.60 ± 10.28 grains∙m−2), the semi-shady slope (382.13 ± 12.11 grains∙m−2), and finally the shady slope (208.00 ± 11.35 grains∙m−2). The seed rain on the sunny slope diffused earliest and lasted the longest, while the seed rain on the shady slope diffused latest and lasted the shortest time. Seed vigor and the proportion of mature seeds within the seed rain were greatest on the semi-sunny slope, followed by the sunny slope, semi-shady slope, and the shady slope. (3) From the end of the seed rain to August of the following year, the amount of total reserves of the soil seed banks was highest on the semi-sunny slope, followed by the sunny slope then the semi-shady slope, and it was the lowest on the shady slope. The amount of mature, immature, gnawed seeds and seed vigor of the soil seed bank in various slope directions showed a decreasing trend with time. The seeds of the seed bank in all slope directions were mainly distributed in the litter layer, followed by the 0–2 cm humus layer, and only a few seeds were present in the 2–5 cm soil layer. (4) The seedling density of Castanopsis hystrix differed significantly on the different slope directions. The semi-sunny slope had the most seedlings, followed by the sunny slope, semi-shady slope, and the shady slope. Conclusions: The environmental conditions of the semi-sunny slope were found to be most suitable for the seed germination and seedling growth of Castanopsis hystrix, and more conducive to the regeneration and restoration of its population.

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