| Nanomaterials have unique physical and chemical properties and are widely used in agricultural production,such as nanometer pesticides,nanometer fertilizers,seed coating agents,soil passivation agents and so on.As the main grain crop in China,high and stable yield of rice is an important guarantee for food security in China.Agricultural use of nanomaterials could help rice production safely.Whether foliar application of nanomaterials will affect the growth of rice,cause stress response of rice and affect the absorption of nutrients in rice remains to be studied.In this study,different nanomaterials were sprayed onto the leaves of rice seedlings to explore the effects of different nanomaterials treatment on the growth of rice seedlings and their phosphorus absorption,so as to provide support for the application of nanomaterials on the leaves to improve the phosphorus content of rice seedlings or promote the phosphorus absorption of rice seedlings.The main findings are as follows:?1?Both nHA+KCl combination and KH2PO4 treatment could promote the growth of rice seedlings and increase the phosphorus content of rice seedlings.And?nHA+KCl?treatment could improve the phosphorus absorption of rice seedlings,and with the increase of treatment concentration,the effect on chlorophyll SPAD and plant height also increased.When the?nHA+KCl?combination was treated with 4 mg·L-1,chlorophyll SPAD and plant height increased the most,which were 16.26%and8.33%,respectively.The effect of?nHA+KCl?treatment was lower than that of KH2PO4 treatment.?2?Spraying 20 nm nano-hydroxyapatite suspension to treat rice seedlings has a certain effect of promoting its growth when it is not higher than 200 mg·L-1.Simultaneous spraying treatment will cause oxidative stress in rice seedlings,and at the same time reduce the activity of Rubisco and chlorophyll SPAD,thus affecting the growth of rice seedlings.The activity of chlorophyll SPAD and Rubisco in rice seedlings was inversely proportional to the treatment concentration.The concentration of peroxidase?POD?in the root of rice seedlings was inversely proportional to that in the root of rice seedlings.The abovemet content is directly proportional to the treatment concentration,and increases the most at the concentration of 500 mg·L-1.The activity of catalase?CAT?in the abovementium and root increased with the increase of treatment concentration.Long-term treatment with 500 mg·L-1concentration maximized the content of superoxide anion?O2.-?and hydrogen peroxide?H2O2?in the abovemet and root of rice seedlings,and the activity of Rubisco enzyme and chlorophyll SPAD were reduced to the minimum.Treatment may activate other antioxidant stress systems,such as ascorbic peroxidase,glutathione reductase,dehydroascorbic reductase,and monodehydroascorbic reductase.In combination with economic benefits and treatment effects,the best treatment effect was obtained for 20 nm nano-hydroxyapatite(100 mg·L-1).?3?The five treatment concentrations(0,50,100,150,200 mg·L-11 and 500 mg·L-1)of nano hydroxyapatite?nHA?,nano ferric oxide?nFe2O3?and nano zero-valent iron?nFe?could promote rice seedlings to different degrees.The biomass was maximized by nFe treatment.Nano hydroxyapatite?nHA?,nano ferric oxide?nFe2O3?,nano zero-valent iron?nFe?,nano ceria?nCe O2?and chitin?CH?of five kinds of materials processing concentration(50,100,150,200 mg·L-11 and 500 mg·L-1)for phosphorus 1/2 of nutrient solution cultivation of rice seedlings were also different degree to promote growth;nHA,n Fe2O3,nFe and nCeO2 treatment significantly promote the absorption of phosphorus.As rice seedlings were cultured normally,the transport coefficient was the highest when n Fe2O3treatment was 500 mg·L-1.Under the condition of 1/2 culture of nutrient solution containing phosphorus,each treatment promoted the transfer of phosphorus to the abovementium,and the transfer coefficient was the highest when nFe2O3 treatment was 100 mg·L-1. |
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